More generator Q's
Existential Angst
So I'm amassing a collection of perm. mag. DC motors for my various
(de)generative follies, but a friend said he took apart a gas powered
generator, and observed no magnets, with both stator and rotor being
wound -- suggesting that AC induction motors should provide juice, but mine
don't.
Was my friend wrong, or can wound rotors/stators yield juice, and if so,
under what conditions?
How are back-up generators generally wound, as well as prime generators,
such as coal, hydro, etc?
Will a typical 3 ph motor throw out juice, if driven by a pony motor?
Any primers on this stuff?
--
EA
Josepi
magnet or electromagnet to produce voltage.
Three phase motors are typically induction types and produce the second
field of magnetism by induction from the wound fields.
Dynamic braking can use the collapsing field while they are turning for a
only short time to generate power but then the field is gone.
--------------------
"Existential Angst" wrote in message
news:4d770100$0$10388$607e...@cv.net...
Ed Huntress
"Existential Angst" <fit...@optonline.net> wrote in message
news:4d770100$0$10388$607e...@cv.net...
> Awl --
>
> So I'm amassing a collection of perm. mag. DC motors for my various
> (de)generative follies, but a friend said he took apart a gas powered
> generator, and observed no magnets, with both stator and rotor being
> wound -- suggesting that AC induction motors should provide juice, but
> mine don't.
>
> Was my friend wrong, or can wound rotors/stators yield juice, and if so,
> under what conditions?
A motor that has both a wound rotor and a wound stator is not, as far as I
know, an AC induction motor. Induction motors have a rotor that's almost
always made up of very short conductors.
Old DC motors often had wound rotors and stators. Until powerful permanent
magnet came along, that's the way all but the smallest DC motors were made.
More than magnet strength, the issue was magnet permanence. All-wound DC
motors generally were of one of three types: series wound, parallel wound,
or series parallel combinations.
That's also the way many DC generators were made. I had an old WWII dynamo
set from a radio Jeep that was made that way. It supplied wire for many of
my ham radio coils back in the '60s.
Used as generators, they need a way to provide initial excitement to at
least one of the coils. There were various setups for this, including
relatively weak magnetized armatures, start batteries, and so on. Once they
were generating current they typically were designed to be self-exciting.
--
Ed Huntress
Winston
(...)
> Used as generators, they need a way to provide initial excitement to at
> least one of the coils. There were various setups for this, including
> relatively weak magnetized armatures, start batteries, and so on. Once they
> were generating current they typically were designed to be self-exciting.
Via parallel capacitors?
http://www.qsl.net/ns8o/Induction_Generator.html
--Winston
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
news:il71g...@news5.newsguy.com...
That's a different situation, Winnie. Those are being used to provide
initial excitement to *induction* motors used as generators. That's a tricky
thing, and I didn't answer EA's question about three-phase induction motors
because it's something with which I have no experience.
But it may well be used to excite some all-wound DC generators, too. 'Don't
know. They were mostly before my time.
--
Ed Huntress
Don Foreman
wrote:
>Your friend was wrong. Motors need a magnetic field, whether permanent
>magnet or electromagnet to produce voltage.
>
>Three phase motors are typically induction types and produce the second
>field of magnetism by induction from the wound fields.
>Dynamic braking can use the collapsing field while they are turning for a
>only short time to generate power but then the field is gone.
>
>--------------------
>
>"Existential Angst" wrote in message
>news:4d770100$0$10388$607e...@cv.net...
>
>Awl --
>
>So I'm amassing a collection of perm. mag. DC motors for my various
>(de)generative follies, but a friend said he took apart a gas powered
>generator, and observed no magnets, with both stator and rotor being
>wound -- suggesting that AC induction motors should provide juice, but mine
>don't.
>
>Was my friend wrong, or can wound rotors/stators yield juice, and if so,
>under what conditions?
Many of the smallish generators (5KW to 50KW) in the Army had wound
rotors. They worked by bootstrapping: remnant magnetism in the iron
generated a small field current, which increased the generated
voltage, increasing the field current.... until the output voltage or
field current reached a threshold where some means of regulation
engaged. Occasionally a generator would fail to generate because
there wasn't enough remnant magnetism to get it going. The solution
was to "pole" the field by applying DC to it to re-magnetize it.
>
>How are back-up generators generally wound, as well as prime generators,
>such as coal, hydro, etc?
>
>Will a typical 3 ph motor throw out juice, if driven by a pony motor?
In a way. It must be excited by the proper 3phase AC voltage, but if
the pony motor then spins the 3phase motor above synchronous speed,
the direction of current flow will be such as to deliver power to the
power line. An electric meter on that line would run backwards.
Tim Wescott
> Awl --
>
> So I'm amassing a collection of perm. mag. DC motors for my various
> (de)generative follies, but a friend said he took apart a gas powered
> generator, and observed no magnets, with both stator and rotor being
> wound -- suggesting that AC induction motors should provide juice, but
> mine don't.
>
> Was my friend wrong, or can wound rotors/stators yield juice, and if so,
> under what conditions?
Generally speaking, older, bigger rotating machines have field windings
that need DC excitation. You can regulate the voltage in a generator by
regulating the current in the field winding. It's exactly the same idea
as a car alternator.
> How are back-up generators generally wound, as well as prime generators,
> such as coal, hydro, etc?
Either with field windings, a motor designed to turn at exactly 1800 (or
3600) RPM to match line frequency, and a regulator connected to the field
windings. More recent ones have inverters, and probably permanent
generators AC generators whose output gets rectified then inverted.
As above, the bigger and older it is, the more likely it is to be a wound-
field synchronous AC machine.
> Will a typical 3 ph motor throw out juice, if driven by a pony motor?
Well, yes, if the stars are aligned right. If you excite it with a
voltage, and turn it faster than its synchronous speed*, then it'll dump
current onto the line instead of sucking current from it. Older small-
time co-generation schemes did this, because maintaining synchronization
is _not_ trivial. Nowadays, it's mostly done with special inverters that
sense the voltage on the line and synchronize the current to the voltage.
> Any primers on this stuff?
I dunno.
* Synchronous speed = 3600, 1800, 1200, etc., on down. So an induction
machine that has a design speed of 3540RPM has a synchronous speed of
3600RPM, and a slip of 1Hz. Turn it up to 3660RPM, and it'll absorb
something close to its rated power while putting almost that much power
onto the line along with some inductive loading.
Winston
Three phase induction? This looks promising:
http://ronja.twibright.com/exciter/
Though the most I could ever accomplish was 70 W for half an hour
a day, so I don't expect to run my house from one of these.
(That parallel FET Q1 cannot be the best possible way
to regulate output power!) Yeesh.
--Winnie
PrecisionmachinisT
"Winston" <Win...@BigBrother.net> wrote in message
http://www.frenchriverland.com/Motors_As_Generators_N_Smith_UK_1994.pdf
--
Winston
> http://www.frenchriverland.com/Motors_As_Generators_N_Smith_UK_1994.pdf
Perused and copied.
Thanks PM!
--Winston
Don Foreman
wrote:
>(That parallel FET Q1 cannot be the best possible way
> to regulate output power!) Yeesh.
>
>--Winnie
"Requires a massive heat sink". Yes, I'll bet it does! Lake Superior
comes to mind...
Josepi
Only reactive power (RVA) will flow back into the line and no "real" power
will flow into the line,except for losses due to heat in the "consumption"
direction.
The kW and kWh meter will not indicate backwards in this situation. The kVAR
and kVARh meters will indicate backward.
This is common with elevators that use their own motors for braking on
descent.
This is nicknamed "rotating capacitor" by some electric utilities and used
to correct power factor on lines and systems.
-----------------------
"Don Foreman" wrote in message
news:bf4en6lale6nl10e7...@4ax.com...
Josepi
It is often stated as putting reactive power back into the supply.
------------------------
"Tim Wescott" wrote in message
news:xfudnRsUMvcajurQ...@web-ster.com...
sta...@prolynx.com
A old-style non-PM DC generator usually relies on residual magnetism
in the pole pieces to start the cycle. One of the to-do items after
working on a VW generator was to connect the battery to the field
windings the correct way round in order to get startup polarity
correct. Just a quick zap to provide some residual magnetism.
A wound alternator needs some DC to start up, one reason you can't
push start a car with an alternator and a totally dead battery. When
I was a kid, my dad took me to visit one of the sites he was currently
working on, was a rural diesel power plant that had had a crankcase
explosion and was being rebuilt. Got the tour from the guys in
charge, had a huge V-16 engine attached to this dinky gray cylinder
about the size of a garbage can. I asked what that was, they said it
was the alternator. Had a tray of batteries sitting on a cart, were
the old squarish cells they used to use for doorbells, all connected
in series. That was the starting DC for the alternator when they were
going from blackout conditions, no juice anywhere.
An AC motor may work as a generator, but you'll have to provide some
method for providing and controlling the field current.
Stan
Wild_Bill
thru a conductor located within in a magnetic field/influence, or a
conductor moved thru a magnetic field are the basic principles.
Finding descriptions of how automotive alternators shouldn't be difficult,
and will likely explain a lot wrt generation.
Many generators utilize brushes, but induction motors can generate under the
proper conditions, as in Winston's referred example.
IIRC, the automotive generators of old cars utilized poles within the
stator/field windings, (and brushes).. the poles weren't permanent magnet
material, but they would hold in a magnet-like state after being properly
magnetized.. same/similar to Don's example.
If you can refer to an older automotive service manual (pre-1970s), you'll
likely find the procedure to stun? the pole pieces in those old generators.
A very weak/slow-motion motor example would be analog panel meters. In the
moving coil type meter movements, the coil (armature) is supported on low
friction pivot points (were jeweled bearings in days of old) within a
magnetic field.
When an appropriate small current flows, the meter needle deflects, and if
the moving coil is rotated manually (not a normal procedure), a small
current flows.
Many new analog meters are packaged with a shorting wire across the
terminals to dampen the needle movement during shipping.. an example of
braking of the generator effect.
Not all analog panel meters employ moving coils, though, and those which
aren't, don't effectively generate any current flow.
Over the years, I've seen a lot of DIY websites showing various generating
techniques from portable/emergency power to wind generation generators that
were made in home shops with powerful magnets (surplus suppliers) and
hand-wound coils on forms and later potted in epoxy or resin.
--
WB
.........
"Existential Angst" <fit...@optonline.net> wrote in message
news:4d770100$0$10388$607e...@cv.net...
Tim Wescott
(top posting fixed)
> "Tim Wescott" wrote in message
> news:xfudnRsUMvcajurQ...@web-ster.com...
> Well, yes, if the stars are aligned right. If you excite it with a
> voltage, and turn it faster than its synchronous speed*, then it'll dump
> current onto the line instead of sucking current from it. Older small-
> time co-generation schemes did this, because maintaining synchronization
> is _not_ trivial. Nowadays, it's mostly done with special inverters that
> sense the voltage on the line and synchronize the current to the voltage.
>
>
>> Will a typical 3 ph motor throw out juice, if driven by a pony motor?
>
>
> voltage.
>
> It is often stated as putting reactive power back into the supply.
Nope, sorry, you're just plain wrong.
Using induction machines as generators is an established -- if slightly
obscure -- practice. Real mechanical power is transformed to real
electric power. There are some inductive VARs, but there's real VARs, too.
But don't argue with me. Argue with the world wide web:
http://en.wikipedia.org/wiki/Induction_generator
http://www.aerostarwind.com/induction_generator.html
http://www.daviddarling.info/encyclopedia/I/AE_induction_generator.html
http://www.electrodynamics.net/documents/electrodynamics_power_gen2002.pdf
(and all the myriad other pages that come up when you search on
"induction generator).
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Josepi
I would love to see an example of this where you turn asynchronous motor at
3660 poles per second on a 60Hz line and it puts ***real*** power back into
the line and the O/C protection stays intact. That is a completely moronic
statement in itself.
You may get some real power out of this machine but not very much. The power
is mostly VAR power and this is done on large grid systems, in many areas.
-----------------------------
"Tim Wescott" wrote in message
news:9YSdnaQQILOnIerQ...@web-ster.com...
Nope, sorry, you're just plain wrong.
Using induction machines as generators is an established -- if slightly
obscure -- practice. Real mechanical power is transformed to real
electric power. There are some inductive VARs, but there's real VARs, too.
But don't argue with me. Argue with the world wide web:
http://en.wikipedia.org/wiki/Induction_generator
http://www.aerostarwind.com/induction_generator.html
http://www.daviddarling.info/encyclopedia/I/AE_induction_generator.html
http://www.electrodynamics.net/documents/electrodynamics_power_gen2002.pdf
(and all the myriad other pages that come up when you search on
"induction generator).
Don Foreman
wrote:
>Not completely true.
>Only reactive power (RVA) will flow back into the line and no "real" power
>will flow into the line,except for losses due to heat in the "consumption"
>direction.
>
>The kW and kWh meter will not indicate backwards in this situation. The kVAR
>and kVARh meters will indicate backward.
>This is common with elevators that use their own motors for braking on
>descent.
>
>This is nicknamed "rotating capacitor" by some electric utilities and used
>to correct power factor on lines and systems.
Don't give up your day job, Josepi.
Existential Angst
That's actually not bad.
How did you determine that it was 70 W?
--
EA
Winston
(...)
> "Requires a massive heat sink". Yes, I'll bet it does! Lake Superior
> comes to mind...
Heh! :)
--Winston
Jon Elson
> Not completely true.
> Only reactive power (RVA) will flow back into the line and no "real"
> power will flow into the line,except for losses due to heat in the
> "consumption" direction.
>
real power, as opposed to reactive. They are often used in small
hydropwer systems, and use the grid as backup and for regulation.
However, there ARE some people who have rigged these up as prime
alternators, and use various schemes to achieve regulation of both
voltage and frequency.
>
> This is nicknamed "rotating capacitor" by some electric utilities and
> used to correct power factor on lines and systems.
>
There used to be large motors used for phase angle correction in large
factories, etc. They had a wound field, and the excitation was
controlled by a phase angle meter, to correct the power factor drawn
from the utility grid. They got a big break on their electric bill for
using such a device. Often called a "rotary condenser".
Jon
Jon Elson
> A motor that has both a wound rotor and a wound stator is not, as far as I
> know, an AC induction motor. Induction motors have a rotor that's almost
> always made up of very short conductors.
>
There is a class of AC induction motor, now rarely seen, that DOES have
a wound rotor and a commutator much like on a DC motor. One difference
is they often have a "bracelet" in the commutator that flies out and
shorts all the segments together when the motor reaches a certain speed.
A variable resistor can be put in series with the brushes to regulate
torque when starting. We have an ancient merry-go-round here that has
such a motor, it takes about 3 minutes to come up to synchronous speed,
which would fry a standard induction motor. The operator slowly cranks
out the resistor as the motor speeds up.
These were also used on streetcars, and a variety of other things that
took a long time to start moving. Now, of course, a VFD would be used.
Jon
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
(...)
>> Three phase induction? This looks promising:
>> http://ronja.twibright.com/exciter/
>>
>> Though the most I could ever accomplish was 70 W for half an hour
>> a day, so I don't expect to run my house from one of these.
>
> That's actually not bad.
> How did you determine that it was 70 W?
At the time, I had an exercise bicycle that used a magnetic
'reluctance brake'. There was a knob next to the handlebar
yoke that I could twist to provide any amount of pedal
resistance. A meter next to it indicated the number of watts
I was converting. It probably wasn't terribly accurate but
it was good enough for a 'ballpark' figure and interesting
for a guy that is ~97% fat :)
Between 'warmup' and 'cool down', I could keep the needle
above 70 W for a half hour, consistently without endangering
my health.
I was very impressed when I learned that world - class
bicyclists can generate over 480 (Four Hundred Eighty)
watts continuously during a one hour time trial!
Dayum.
--Winston <-- Now walking around, turning off room lights.
BobH
> A wound alternator needs some DC to start up, one reason you can't
> push start a car with an alternator and a totally dead battery.
That is not strictly true. I drove a 72 AMC (with a Motorola Alternator)
for months without a battery in it. The alternator retains enough
magnetism to self excite enough to fire the coil. This was a carburated
straight 6. I lived and worked in a hilly area. If I killed it in
traffic, I was hosed.
A newer fuel injected vehicle requires enough current to run the fuel
pump and the computer in addition to the coil, so you be walking now.
BobH
spaco
Existential Angst wrote:
> How are back-up generators generally wound, as well as prime generators,
> such as coal, hydro, etc?
I have a couple of 6.5 KW Onan 120/240 volt 60hz generators. They both
have wound rotors and stators. One takes the power off the rotor via
slip rings and the other (newer) takes the power off the stator. In
this case the field,(the rotor) has dc supplied to it via slip rings.
Even though there is usually enough residual magnetism to get generation
going, both sets "flash" the field with some of the starting battery
juice to make sure the field current builds up quickly.
>
> Will a typical 3 ph motor throw out juice, if driven by a pony motor?
Yes. I bought the Nigel Smith book mentioned in another post on this
thread. I focused on the setup called "C-2C", using a 3 phase motor to
produce single phase ac power. It does work. I am using a 5 hp 3 phase
electric motor which is being driven by a 12 hp Briggs gasoline engine
that is running at about 2200 rpm and belted to produce 60 hz at that
engine speed.
>
> Any primers on this stuff?
Yes, The Nigel Smith book is the one to get. Also, type "induction
generator" into youtube and you won't see the light of day for about a week.
Pete Stanaitis
------------------
Josepi
induce a current into one of the coils and excite the other one. With motion
energy applied this can feed itself (self excite), as if the battery was
there, once in motion.
Without two sets of windings this doesn't happen.
---------------
"BobH" wrote in message news:il922...@news2.nntpjunkie.com...
Existential Angst
I wouldn't be too impressed, just yet..... :)
480 W for a continuous hour is proly some laboratory confabulation, from
devices that are not measuring watts, but calculating/inferring watts.
A lot of these bicycle watt meters are "watt calculators" from piezo sumpn
strain gauges/load cells, not from true generated electrical power. Dollars
to donuts, if you tested these guys on a real generator, you'd get far more
modest results.
Here's why:
If you calc backwards from a 480 watt mechanical output, you wind up with a
VO2 of 100.
Keep in mind that the elite of the elite possess VO2 *MAXes* of about 95,
and VO2max is a semi-instantaneous value, NOT a sustained value.
I'll have to check, but I think VO2max need only be sustained for a fraction
of a minute to qualify as VO2 max.
Sustained (aerobic) VO2s are usually *maybe* 80% of VO2max values. And that
last 20% is almost exponential in its perceived exertion, ie, quite
unsustainable.
Iow, a marathon runner may win a race at 80% of his VO2max (2+hours), but if
he "miscalculates", and runs at 90%, he may crap out after 1/2 hour -- or
sooner.
Marathon runners are toodling along at 18-20 cals/min, while your above
cyclist is calc'ing out at 34 cals/min -- which is unheard of, on a
sustained basis -- at least for 150 lb. guys. 300# -- mebbe..... :)
I'll post the calcs iffin inyone is innerested, basically just conversions.
Was *your* 70 W really 70 watts? Hard to say.
I can tell you that I can run for a solid hour (if you pay me), albeit not
at any earth-shaking pace, but at 180# and with hills, that is some
effort/expenditure.
The point being, I couldn't keep a 100 W lite bulb lit up for more than 3
minutes, a few days ago, on my cycle-generator.
Now, I think I'm getting better quickly, as I haven't cycled in literally 40
years, but still, even with substantial improvement, 1/2 hour at that output
is proly beyond my wherewithall -- both physical AND psychological!
100 W calcs out to a moderate but still substantial 10 cal/min, but in
reality is certainly more, depending on the efficiency of a PM DC motor.
Inyway, just some perspective on some of these hyooge wattage claims.
A little more perspective:
Some cyclists claim 2000 W peak outputs, which I might believe, over a
second or two.
Powerlifters have been measured at near-10,000 W instantaneous efforts, no
doubt over fractions of a second, possibly milliseconds. Staggering, when
you think about it.
But, what you can do for second is a *whole* lot different than what can be
done for 10 secs, 1 min, 5 min, 10 min, 1 hour.
And then, of course, you have the HSN/QVC pod peeple, effervescing: Oh,
Oh, OH, I just burntid 500 cals in 1/2 hour, and dint even knowed it!!!!!
Not hardly, sweetheart..... If you burntid 500 cals in 1/2 hour, you
likely woudn't be goin to work the next day.....
--
EA
Ed Huntress
FWIW, when the Gossamer Albratross crossed the English Channel, which took 2
hours and 49 minutes, the power required in still air was said to be 0.4
hp -- about 300 W, on average. That assumed still air. Normal disturbances
increase the horsepower required.
Here's a quote from a cometitive cyclist and engineer. It agrees with what I
was told when I competed in road sprints, back when tires were made of cast
iron <g>:
"Most fit adults can produce 100 watts (0.134 horsepower) of mechanical
power on a bicycle for a sustained period. A world-class competitive cyclist
can produce up to 500 watts (0.67 horsepower) over a sustained period of
time."
Of course, you'll get a lot less from a small generator. IIRC, automobile
alternators are something like 60% efficient, and there is the mechanical
loss involved in driving them. Permanent-magnet alternators in the same
size, however, are said to be up to 90% efficient. Don't ask me.
--
Ed Huntress
Winston
(...)
> Was *your* 70 W really 70 watts? Hard to say.
I don't really know for sure. That's just what the instrument
indicated. :)
--Winston
Winston
> "Existential Angst"<fit...@optonline.net> wrote in message
> news:4d7843dc$0$13015$607e...@cv.net...
>> "Winston"<Win...@BigBrother.net> wrote in message
>> news:il8uc...@news3.newsguy.com...
(...)
>>> Between 'warmup' and 'cool down', I could keep the needle
>>> above 70 W for a half hour, consistently without endangering
>>> my health.
>>>
>>> I was very impressed when I learned that world - class
>>> bicyclists can generate over 480 (Four Hundred Eighty)
>>> watts continuously during a one hour time trial!
>>>
>>> Dayum.
>>
>> I wouldn't be too impressed, just yet..... :)
(...)
>> --
>> EA
>
> FWIW, when the Gossamer Albratross crossed the English Channel, which took 2
> hours and 49 minutes, the power required in still air was said to be 0.4
> hp -- about 300 W, on average. That assumed still air. Normal disturbances
> increase the horsepower required.
>
> Here's a quote from a cometitive cyclist and engineer. It agrees with what I
> was told when I competed in road sprints, back when tires were made of cast
> iron<g>:
We would have killed for cast iron.
They made *us* knap our tires from granite. :)
> "Most fit adults can produce 100 watts (0.134 horsepower) of mechanical
> power on a bicycle for a sustained period.
That is believable considering that a physically compromised
middle - aged schlub managed 70 W for 30 minutes twice a week.
> A world-class competitive cyclist
> can produce up to 500 watts (0.67 horsepower) over a sustained period of
> time."
Stunning!
> Of course, you'll get a lot less from a small generator. IIRC, automobile
> alternators are something like 60% efficient, and there is the mechanical
> loss involved in driving them.
..And the often - ignored massive amount of power needed for the
field winding.
> Permanent-magnet alternators in the same
> size, however, are said to be up to 90% efficient. Don't ask me.
Thus their use in 'n'+1 alternative energy devices:
http://www.google.com/search?hl=en&source=hp&q="PM+alternator"+&aq=f&aqi=g1g-v9&aql=&oq=
--Winston
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
Oh, c'mon. Now you're exaggerating. It takes too long to knap tires from
granite. There probably are some RCM members who have tried...
>
>> "Most fit adults can produce 100 watts (0.134 horsepower) of mechanical
>> power on a bicycle for a sustained period.
>
> That is believable considering that a physically compromised
> middle - aged schlub managed 70 W for 30 minutes twice a week.
>
>> A world-class competitive cyclist
>> can produce up to 500 watts (0.67 horsepower) over a sustained period of
>> time."
>
> Stunning!
>
>> Of course, you'll get a lot less from a small generator. IIRC, automobile
>> alternators are something like 60% efficient, and there is the mechanical
>> loss involved in driving them.
>
> ..And the often - ignored massive amount of power needed for the
> field winding.
I think that the 60% includes the power lost by exciting the field. Again,
going from memory, I think that automobile alternators are reluctance-type.
They're flexible but not particularly efficient.
Existential Angst
news:4d78480b$0$1390$607e...@cv.net...
I hope "a sustained period" = three minutes! LOL!!!!
Makes you wonder how one defines "most fit adults"....
Heh, you *could* make it foolproof/tautological by defining fit adults as
those who can generate 100 W for 1/2 continuous hours.... LOL!!!
A world-class competitive cyclist
> can produce up to 500 watts (0.67 horsepower) over a sustained period of
> time."
I'll believe dat shit when I see five 100 W bulbs at full brightness for a
solid hour..... :)
Previously, I managed 2:45. Just now I managed 3:30... that's
minutes/seconds... LOL!!!
Now, "manage" is really context sensitive... at what point does one
"quit"?
With no objective blood/lab values, that's really a dicey Q for true
reproducibility, so I use a kind arbitrary "pain threshhold": where I'm
whining for my mommy, but not yet screaming for her....
I suspect Thurs or Fri I'll be up to 5 minutes, and mebbe 10 minutes in
another week, but the point is, Goddamm, I fairly regularly run a hilly full
1/2 hour (2.5 miles or so), so if 100 TRUE watts is hard for me.....
Now, I estimated the driveline friction at about 12 W, and mebbe the PM
motor (perty old... how can I tell? cuz it's not made like shit....) is
80% efficient??
So ackshooly, that adds up to 137 W....
But proly other true bicycle generators would similar characteristics....
but not these "interpreted cycle watt-meters"....
So the comparison issue is still a begged issue.... Who really knows WTF is
up with internal losses, or even true wattage readings, eh? So how do we
really compare results, over the internet with diff setups?
>
> Of course, you'll get a lot less from a small generator. IIRC, automobile
> alternators are something like 60% efficient, and there is the mechanical
> loss involved in driving them. Permanent-magnet alternators in the same
> size, however, are said to be up to 90% efficient. Don't ask me.
Funny, high efficiency motors are sposedly > 98% efficient.... 3 ph, no
doubt.
--
EA
>
> --
> Ed Huntress
>
Josepi
that sensitive to relative lighting.
Talk about using actual power measurements...LOL
--------------
"Existential Angst" wrote in message
news:4d7843dc$0$13015$607e...@cv.net...
I wouldn't be too impressed, just yet..... :)
Josepi
----------------
"Winston" wrote in message news:il9il...@news2.newsguy.com...
I don't really know for sure. That's just what the instrument
indicated. :)
---------------
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
> news:il9jk...@news7.newsguy.com...
(...)
>> We would have killed for cast iron.
>> They made *us* knap our tires from granite. :)
>
> Oh, c'mon. Now you're exaggerating.
Busted. Curses!
> It takes too long to knap tires from
> granite. There probably are some RCM members who have tried...
Doubtlessly.
> I think that automobile alternators are reluctance-type.
> They're flexible but not particularly efficient.
I see where Bosch are touting their new 70% efficient 'smart'
alternator that allows digital control so that field
current can be turned off during acceleration and
cranked up during braking, boosting engine efficiency
by as much as 3%. Smart Indeed!
http://csr.bosch.com/content/language2/html/3180_ENU_XHTML.aspx
--Winston
Existential Angst
news:YZYdp.1120$Di7...@newsfe08.iad...
> Probably much more accurate then an estimate of a 100W bulb brightness.
First, not an informed statement, as most fitness mfr's don't really care
what a watt even is, never mind actually making accurate calibrations
against a standard.
Second, there is no estimating of bulb brightness if you've got a voltmeter
in front of you, and you are maintaining 120 V. This then becomes as
accurate as anything, short of accurate/expensive regulators, solidstate
integrators, etc.
--
EA
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
These innovations are great to think about. Then it comes time to analyze
something gone wrong...
Speaking of which, my wife's Sonata died today -- the battery died because
her passenger left the door ajar at lunchtime -- and I was freaked when I
went over to school to jump start it. The intrusion alarm was feebly wailing
a plaintive cry, like a baby animal that was being torn apart by a raptor or
something, and I couldn't get it to stop. There was just enough juice left
in the battery to give out that feeble squeak, but not enough to react to
the remote. When I connected the jumper cables it went into full blast --
with my head under the hood and about 18 inches from the alarm. Jesus. I
didn't know I could still jump like that.
I want something I can fix with a screwdriver and a box of tools I could put
under my arm. A Lotus 6 or 7 might do it. No doors, even.
--
Ed Huntress
Existential Angst
>I highly doubt you can tell if a 100W bulb is lit 100%. The human eye is
>not that sensitive to relative lighting.
>
> Talk about using actual power measurements...LOL
At first, I didn't understand why others here call you an asshole....
Oh, and btw, prior to the digital age, laboratory pyrometers were exactly
based on relative brightness, which could be assessed with some precision.
If you wanted to be real anal (speaking of assholes), you could have a bulb
powered from a wall outlet, and then power the bike-driven bulb to
comparative brightness, quite accurately.
But, as I stated in my other reply to you, a much better solution is to
simply monitor a voltmeter while powering the bulb.
Are you still LOLing???
--
EA
PrecisionmachinisT
"Josepi" <J.R.M.@greasynews.calm> wrote in message
> (moronic posting format fixed)
>
> I would love to see an example of this where you turn asynchronous motor
> at 3660 poles per second on a 60Hz line and it puts ***real*** power back
> into the line and the O/C protection stays intact. That is a completely
> moronic statement in itself.
>
Not sure about the 3660 poles per second part but pretty sure just about
every windmill that is placed onto the grid does exactly this.
--
PrecisionmachinisT
"spaco" <sp...@baldwin-telecom.net> wrote in message
news:wNWdnaZttcXjveXQ...@bright.net...
FWIW,
I have had the Nigel Smith book for nearly a decade now-actually bought the
thing--if there is a prolonged power outage here what I do is I run a 50 hp
3ph motor as a single phase induction generator off from my 23 hp kubota
tractor PTO--which easily powers the entire house including starting a 5 ton
heat pump compressor..
C2C connection gives you single phase off of a 3 phase motor, rpm ( 60 hz )
is via throttle governor and isnt particularily critical, 20% is probably
okay but if in doubt use a ole telechron clock, and compare with a quartz
unit..they bothe should read within a few seconds after a minute's time on
line...if not, then adjust your throttle to suit.
--
Winston
(...)
> These innovations are great to think about. Then it comes time to analyze
> something gone wrong...
One More Thing To Break.
> Speaking of which, my wife's Sonata died today -- the battery died because
> her passenger left the door ajar at lunchtime -- and I was freaked when I
> went over to school to jump start it. The intrusion alarm was feebly wailing
> a plaintive cry, like a baby animal that was being torn apart by a raptor or
> something, and I couldn't get it to stop. There was just enough juice left
> in the battery to give out that feeble squeak, but not enough to react to
> the remote. When I connected the jumper cables it went into full blast --
> with my head under the hood and about 18 inches from the alarm. Jesus. I
> didn't know I could still jump like that.
Queue sympathetic headache. Ouch!
> I want something I can fix with a screwdriver and a box of tools I could put
> under my arm. A Lotus 6 or 7 might do it. No doors, even.
I've owned 'simple' cars.
I *will not* go back to carburetors, for I have *seen* the glory
of fuel injection on a cold and dreary morning!
I *will not* return to breaker points for I have known the
power of the Fat White Electronic Ignition Spark!
I *will not* slide back to the days of the bias ply tire
for I have sat in awe over the Indestructible Radial Ply!
Can I get an Amen, brothers and sisters.
--Winston <-- Happy Herbert Akroyd Stuart Day to all
and to all a good night.
Don Foreman
wrote:
>>
>There used to be large motors used for phase angle correction in large
>factories, etc. They had a wound field, and the excitation was
>controlled by a phase angle meter, to correct the power factor drawn
>from the utility grid. They got a big break on their electric bill for
>using such a device. Often called a "rotary condenser".
Those are over-excited synchronous motors.
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
...As long as it isn't late Saturday night and you're in the boondocks. My
trunk is lighter these days, however, without two stuffed toolboxes in the
trunk.
--
Ed Huntress
Josepi
estimation of brilliance providing you knew the "standard" one was being
powered by exactly the rated voltage. Since power is proportional to the
square of the applied voltage the power and therefore the brilliance could
be somewhat off for the purposes of good measurement.
You mentioned accuracy of measurement but then mentioned your light bulb
method in a seemingly contradiction of your intent.
Apparently it was just a troll for childish attention. Did you have trouble
in school with the other children rejecting you, too?
----------------------
"Existential Angst" wrote in message
news:4d78637c$0$10365$607e...@cv.net...
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
> news:il9ph...@news7.newsguy.com...
(...)
>> I've owned 'simple' cars.
>>
>> I *will not* go back to carburetors, for I have *seen* the glory
>> of fuel injection on a cold and dreary morning!
>>
>> I *will not* return to breaker points for I have known the
>> power of the Fat White Electronic Ignition Spark!
>>
>> I *will not* slide back to the days of the bias ply tire
>> for I have sat in awe over the Indestructible Radial Ply!
>>
>> Can I get an Amen, brothers and sisters.
>
> ...As long as it isn't late Saturday night and you're in the boondocks.
I'll make that trade! I spent many lost weeknights and
weekends under the hood so that I could make it to work the next
day. Fergit that, man! :)
Let us not forget the blessing of the Onboard Diagnostics!
When things (rarely) do go pear-shaped, the OBD is a
heck of a time saver. Imagine troubleshooting an intermittent
sensor problem without it. (Shudder)
> My trunk is lighter these days, however, without two stuffed toolboxes
> in the trunk.
As is mine! (Though the boxes remained in the trunk a while
before I noticed that my Japanese - designed car wasn't failing.)
Reliability leads to better gas mileage. Who knew?
--Winston
pent...@yahoo.com
<dfor...@NOSPAMgoldengate.net> wrote:
>>
>>Will a typical 3 ph motor throw out juice, if driven by a pony motor?
>
>In a way. It must be excited by the proper 3phase AC voltage, but if
>the pony motor then spins the 3phase motor above synchronous speed,
>the direction of current flow will be such as to deliver power to the
>power line. An electric meter on that line would run backwards.
For UK residents but may apply elsewhere. The old analogue
electric power meters happily spun forwards or backwards to read
power consumed or power fed back into the supply. In the UK the
supply authorities are now replacing them with digital meters
that are programmed NOT to register negative power. Power fed
back into the supply will be happily accepted by the supply
authority but will not reduce the meter reading.
Not sure why they are programmed this way but the effect with
many Solar PV tariffs is to reduce the claimed saving In the
nett electricity bill. Power that is registered outside daylight
hours cannot be reduced or cancelled by daylight solar energy.
Jim
Josepi
DC and then runs a solid-state co-gen inverter system to grid tie and
synchronise.
Here is another quote from another method used on larger units.
The doubly fed generator bleeds a small bit of ac power off the utility grid
and converts it to a signal that creates the wound rotor’s magnetic field at
low wind speeds, when the generator is spinning at below its synchronous
speed. Fast electronics control the spinning rotor’s magnetic field such
that the generator puts out a 60-Hz signal even when it is turning slowly.
(Above synchronous speed, the rotor of doubly fed generators produce power
to the grid.)
------------------------------------------
"PrecisionmachinisT" wrote in message
news:Q5CdnZE3QNK5-eXQ...@scnresearch.com...
Josepi
How do you excite the windings ?
-------------------------------------------
"PrecisionmachinisT" wrote in message
news:nfWdna96f6is-uXQ...@scnresearch.com...
Existential Angst
> Yes, having two light bulbs with one as a standard could help your
> estimation of brilliance providing you knew the "standard" one was being
> powered by exactly the rated voltage. Since power is proportional to the
> square of the applied voltage the power and therefore the brilliance could
> be somewhat off for the purposes of good measurement.
>
> You mentioned accuracy of measurement but then mentioned your light bulb
> method in a seemingly contradiction of your intent.
Ergo the voltmeter. What part of E^2/R don't YOU get???
And true, since the voltage is squared, you'll proly want to squint a bit
harder at the volt reading.....
Man, iffin you cain't get simple notions of resistive power correck, wtf are
you doing blabbering about complicated shit, like motors??
What did someone say..... don't quit yer day job??
>
> Apparently it was just a troll for childish attention.
No, it was the natural evolution of thread drift, from someone else who
mentioned wattage from exercise.
Did you have trouble
> in school with the other children rejecting you, too?
A bit, but mostly because I was already very good looking as a kid, and had
an 8" dick in the 6th grade.
fyi, it's now 12", and at your service.....
Did you have trouble with the kids beating the everlovin shit out of you??
Are you replacing Jon Banquer?
Who's now pushing a hotdog cart somewhere in Chula Vista....
Nothing wrong with that, btw, just that *I* wouldn't buy a hot dog from jb,
even it was irradiated with gamma rays.
--
EA
Josepi
approved...yet...until somebody thinks of it...shhhhhhh.
It would make sense as they do not want your extra energy in off peak hours.
They are try to give the stuff away, already.
-------------------
wrote in message news:mimhn6pt1a4fqag9d...@4ax.com...
Ned Simmons
wrote:
>Yes, having two light bulbs with one as a standard could help your
>estimation of brilliance providing you knew the "standard" one was being
>powered by exactly the rated voltage. Since power is proportional to the
>square of the applied voltage the power and therefore the brilliance could
>be somewhat off for the purposes of good measurement.
The brilliance (using the term loosely) is proportional to
voltage^3.5. In other words, a small change in voltage results in a
relatively large change in "brilliance".
--
Ned Simmons
Josepi
filament is a dynamic resistance, but where did you get the 3.5 exponent?
-----------
"Ned Simmons" wrote in message
news:1mshn6d5cuksb0sqn...@4ax.com...
Existential Angst
news:1mshn6d5cuksb0sqn...@4ax.com...
That's inneresting -- from Stefan-Wien's law or sumpn?? Blackbody
radiation?
So this would make comparative brilliance not such a bad indicator -- mebbe
why optical pyrometers were pretty accurate?
But, any way you cut -- monitoring brilliance or voltage -- yer error is a
whole lot less than this confabulated bullshit in the fitness market.
--
EA
>
> --
> Ned Simmons
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
> Ed Huntress wrote:
>> "Winston"<Win...@BigBrother.net> wrote in message
>> news:il9ph...@news7.newsguy.com...
[If this is showing up multiple times, my apology. My 'puter's clock screwed
up; I thought I deleted the first reply; wrote a second reply; and lost that
one, too. My "sent" box says I sent them in 2001. <g>]
>
> (...)
>
>>> I've owned 'simple' cars.
>>>
>>> I *will not* go back to carburetors, for I have *seen* the glory
>>> of fuel injection on a cold and dreary morning!
>>>
>>> I *will not* return to breaker points for I have known the
>>> power of the Fat White Electronic Ignition Spark!
>>>
>>> I *will not* slide back to the days of the bias ply tire
>>> for I have sat in awe over the Indestructible Radial Ply!
>>>
>>> Can I get an Amen, brothers and sisters.
>>
>> ...As long as it isn't late Saturday night and you're in the boondocks.
>
> I'll make that trade! I spent many lost weeknights and
> weekends under the hood so that I could make it to work the next
> day. Fergit that, man! :)
>
> Let us not forget the blessing of the Onboard Diagnostics!
> When things (rarely) do go pear-shaped, the OBD is a
> heck of a time saver. Imagine troubleshooting an intermittent
> sensor problem without it. (Shudder)
I don't have a diagnostic scanner. Just a sign under the hood that says
"Abandon hope, all ye who enter here." And there is prayer.
>
>> My trunk is lighter these days, however, without two stuffed toolboxes
>> in the trunk.
>
> As is mine! (Though the boxes remained in the trunk a while
> before I noticed that my Japanese - designed car wasn't failing.)
You didn't have an '87 Mazda 626 with manual transmission. Mine was rebuilt
twice, and I'm really easy on the gearbox. Mazda won't admit they made cars
that year.
>
> Reliability leads to better gas mileage. Who knew?
I admire the cars made today. They just don't fit my lifestyle. My '67 Ford
Bronco saw a lot of off-road duty, and the inside looked like you could hose
it down to clear out the mud. The inside of an SUV today looks like the
lobby of a New Orleans whorehouse, with surround sound. The only thing
missing is the crystal chandelier.
--
Ed Huntress
KD7HB
> I want something I can fix with a screwdriver and a box of tools I could put
> under my arm. A Lotus 6 or 7 might do it. No doors, even.
>
> --
> Ed Huntress
Lotus 7, huh. I remember going to a British car dealer in the 1960's to check out a '7' and I could not get my feet down to where the peddles were. I suppose if I took my shoes off, it would work. I dearly wanted to test drive that car.
Oh, well. In reality, we couldn't afford it.
Paul
Ed Huntress
"KD7HB" <co_f...@yahoo.com> wrote in message
news:ec387830-933a-461a...@glegroupsg2000goo.googlegroups.com...
I'm 5'9" and have a couple of friends with old Lotuses (Super 7 America Mk
IV, and a '63 Elan). They're just made for me. I think it was _Car & Driver_
that described the seats in the Super 7 Mk IV: "The word often used to
describe supportive seating in a sports car is 'caress.' These seats are
more like being gripped in the jaws of an enraged clam."
The Lotus 6 had a plank for a seat with a piece of canvas, or maybe an old
T-shirt, glued to it. It weighed around 950 pounds, dry.
However, even I feel claustrophobic in a Lotus Europa. If you're over 5'11",
your head squashes the headliner. No kidding.
>
> Oh, well. In reality, we couldn't afford it.
I debated over a Super 7 in 1967, and again in '72. But I had to drive
between NJ and Michigan in those days, and winter driving made it too
unappealing. The Super 7 in kit form was $2,800 in '67. I don't know what
the assembled price was, but you could bolt one together over a couple of
weekends.
--
Ed Huntress
Ned Simmons
wrote:
>I know it is not completely linear to the square of the voltage, as the
>filament is a dynamic resistance, but where did you get the 3.5 exponent?
>
From memory (I knew the exponent was approx 4), confirmed by
Wikipedia. Fink's "Standard Handbook for Electrical Engineers" says
3.38.
--
Ned Simmons
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
(...)
>> Let us not forget the blessing of the Onboard Diagnostics!
>> When things (rarely) do go pear-shaped, the OBD is a
>> heck of a time saver. Imagine troubleshooting an intermittent
>> sensor problem without it. (Shudder)
>
> I don't have a diagnostic scanner. Just a sign under the hood that says
> "Abandon hope, all ye who enter here." And there is prayer.
My scanner has produced miracles that would have started
religions 100 years ago. Consistently, too. :)
> You didn't have an '87 Mazda 626 with manual transmission. Mine was rebuilt
> twice, and I'm really easy on the gearbox. Mazda won't admit they made cars
> that year.
Mazda were very slow learners, then.
In '76 I remember absolutely trashing the manual transmission
on the company Mazda pickup, on the way back from the airport
after picking up my boss and the lead sales guy!
I wasn't being aggressive or anything. One moment it was
working fine and the next it was an inert pile of metal.
None of us were particularly happy, that afternoon.
(...)
> I admire the cars made today. They just don't fit my lifestyle. My '67 Ford
> Bronco saw a lot of off-road duty, and the inside looked like you could hose
> it down to clear out the mud. The inside of an SUV today looks like the
> lobby of a New Orleans whorehouse, with surround sound. The only thing
> missing is the crystal chandelier.
Tacky. And not in a good way.
http://www.youtube.com/watch?v=e4QgWRycd7I&feature=related
--Winston
Ed Huntress
"Winston" <Win...@BigBrother.net> wrote in message
That's one of my favorite Simpson's routines. I think my neighbor has one of
those. When gas hits $4/gallon, they just leave it parked in the driveway
and worship it.
--
Ed Huntress
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
(...)
>> Tacky. And not in a good way.
>>
>> http://www.youtube.com/watch?v=e4QgWRycd7I&feature=related
>
> That's one of my favorite Simpson's routines. I think my neighbor has one of
> those. When gas hits $4/gallon, they just leave it parked in the driveway
> and worship it.
That's the fourth time today you made me laugh out loud.
Thanks Ed.
--Winston <-- "Angry clam, my ass"
Josepi
If the filament was a straight fixed resistor the power would be the square
of the voltage only.
Since the filament increases resistance with heat the resistance is not
constant and would decrease the voltage squared factor to less than 2. It
should be noted that the resistance is probably not linearly proportional to
the power as there is heat leakage factors and irradiation that will affect
the linearity of that too.
Now we are talking about brilliance of illumination and not power per se, so
another conversion factor enters into it.
DO we know (any links) what the relationship of a filament bulb lumens
output to power in is. There should be some charts. If we can establish it
has an almost squared element (pun noted) then we can basically verify this
3.38 or something to that effect.
Sounding more reasonable all the time and would make a light bulb a really
sensitive power level indicator. Especially when compared to a standard
known illumination.
Thanx for the info!
------------------------------------------
"Ned Simmons" wrote in message
news:896in65ah9nmvf7e1...@4ax.com...
Sunworshipper
Strange, I had a '72 Mazda RX2 and the shifting was one of the best.
It would even find reverse at 30 mph forward and 2nd while going 30
mph backwards and break the tires loose. I tried really hard to break
one once. That car died valiantly. Probably no compression or welded
triangular rotor to the block from over heating.
SW
Ed Huntress
"Sunworshipper" <SW@GWNTUNDRA> wrote in message
news:ghjin6hp3hqvf4pg3...@4ax.com...
The 5-speed gearbox in the '87 626 had an all-new housing design, to save
some weight and cost, and it had very narrow bearings and shallow and
thin-walled bearing bosses. The bearings would wear loose in their seats.
And, because they were thinner than their standard design, the bearings and
races themselves weren't as strong and would run out; the play in the shafts
would become excessive; and the varying load that resulted from the wear
accelerated the bearing wear. In one ten-mile stretch, I successively lost
third, second, and fourth gear. I limped home with first and fifth.
A year later, the same thing happened. But this time, the whole box bound up
tight. No gears at all.
In '88, Mazda reverted to their pre-'87 design.
--
Ed Huntress
dan
rec.crafts.metalworking on Tue, 8 Mar 2011 23:24:34 -0500:
>Awl --
Should be spelled "All".
>
>So I'm amassing a collection of perm. mag. DC motors for my various
>(de)generative follies, but a friend said he took apart a gas powered
>generator, and observed no magnets, with both stator and rotor being
>wound -- suggesting that AC induction motors should provide juice, but mine
>don't.
>
>Was my friend wrong, or can wound rotors/stators yield juice, and if so,
>under what conditions?
You would like the 'book' _alternator secrets_ . Covers automotive
alternators mostly, but has a section on using induction motors as
generators. I got my copy from lindsay publications.
http://www.lindsaybks.com/index.html
From what I remember, you may need to hit the windings with some
current to get things started. A car battery should do, just for a
second.
--
Dan H.
northshore MA.
jk
>Not completely true.
>Only reactive power (RVA) will flow back into the line and no "real" power
>will flow into the line,except for losses due to heat in the "consumption"
>direction.
>
>The kW and kWh meter will not indicate backwards in this situation. The kVAR
>and kVARh meters will indicate backward.
>This is common with elevators that use their own motors for braking on
>descent.
>
>This is nicknamed "rotating capacitor" by some electric utilities and used
>to correct power factor on lines and systems.
Not true, or only a little so.
A 3 Ph induction motor WILL output power to the grid, WHEN RUN OVER
SYNCHRONOUS SPEED. THis is NOT a rotating capacitor! It will still be
"consuming" reactive power (vars) just like it was when running as a
motor. This is an induction generator. THey are commonly found in wind
turbines, and pumped storage systems.
A rotating condenser (capacitor) is a SYNCHRONOUS motor that is
excited past unity power factor on it's field winding. [i.e. more
excitation than needed when running as a motor] it is rotating at
exactly synchronous speed. Attempt to rotate it faster (by sticking a
primer mover on it) and you have a generator. Put a load on the shaft
and you have a motor.
>
>-----------------------
>"Don Foreman" wrote in message
>news:bf4en6lale6nl10e7...@4ax.com...
>In a way. It must be excited by the proper 3phase AC voltage, but if
>the pony motor then spins the 3phase motor above synchronous speed,
>the direction of current flow will be such as to deliver power to the
>power line. An electric meter on that line would run backwards.
>
>
>>Will a typical 3 ph motor throw out juice, if driven by a pony motor?
>
jk
PrecisionmachinisT
"Josepi" <J.R.M.@greasynews.calm> wrote in message
> Nice.
>
> How do you excite the windings ?
>
2 Capacitors
Don Foreman
wrote:
>square of the applied voltage
Not in an incandescant lightbulb.
Michael A. Terrell
Josepi wrote:
>
> Yes, having two light bulbs with one as a standard could help your
> estimation of brilliance providing you knew the "standard" one was being
> powered by exactly the rated voltage. Since power is proportional to the
> square of the applied voltage the power and therefore the brilliance could
> be somewhat off for the purposes of good measurement.
Lightbulbs are not a linear load. Their resistance goes up as the
voltage increases. You would need to monitor the voltage and the current
to get anything useful.
--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.
Josepi
"rotating capacitors" for power factor correction usage and would find that
interesting . Mostly I worked with smaller motors under 5HP, transformers
and transmission lines and communication stuff. The few PH correction
capacitors we had were static units under 60 MVARs and I would think the
protection circuits would be simpler.
-------------
"jk" wrote in message news:g9vin6p9b1jap7o2h...@4ax.com...
Not true, or only a little so.
A 3 Ph induction motor WILL output power to the grid, WHEN RUN OVER
SYNCHRONOUS SPEED. THis is NOT a rotating capacitor! It will still be
"consuming" reactive power (vars) just like it was when running as a
motor. This is an induction generator. THey are commonly found in wind
turbines, and pumped storage systems.
A rotating condenser (capacitor) is a SYNCHRONOUS motor that is
excited past unity power factor on it's field winding. [i.e. more
excitation than needed when running as a motor] it is rotating at
exactly synchronous speed. Attempt to rotate it faster (by sticking a
primer mover on it) and you have a generator. Put a load on the shaft
and you have a motor.
Josepi
Where are they used? Was there a second set of windings on the rotor,
armature, stator, field laminations?
Is there a circuit available online or of a work-alike?
---
"PrecisionmachinisT" wrote in message
news:_eidnR-VT7nSOuTQ...@scnresearch.com...
2 Capacitors
"Josepi" <J.R.M.@greasynews.calm> wrote in message
news:Fr5ep.20960$vr....@newsfe13.iad...
Nice.
How do you excite the windings ?
Josepi
then.
----
"dan" wrote in message news:4d7960e4...@news20.forteinc.com...
Sunworshipper
<hunt...@optonline.net> wrote:
1st and 5th not good. A friend lent me a car when my '70 MGB got
vandalized, was something like a '70 Toyota Celica with only 2nd and
4th. for a couple of weeks. The MG shifted fantastically well.
SW
Rich Grise
> Josepi wrote:
>>
>> Yes, having two light bulbs with one as a standard could help your
>> estimation of brilliance providing you knew the "standard" one was being
>> powered by exactly the rated voltage. Since power is proportional to the
>> square of the applied voltage the power and therefore the brilliance
>> could be somewhat off for the purposes of good measurement.
>
> Lightbulbs are not a linear load. Their resistance goes up as the
> voltage increases. You would need to monitor the voltage and the current
> to get anything useful.
>
increases. :-)
Cheers!
Rich
Rich Grise
> Nice.
>
> How do you excite the windings ?
>
Gently stroke them while saying romantic things.
Hope This Helps!
Rich
Existential Angst
news:ilej90$oqi$2...@news.eternal-september.org...
Does anyone know what this curve looks like? I would actually like a V vs.
I curve for a typical incandescant.
Googled some, wiki has an inneresting table on incandescant efficiency
http://en.wikipedia.org/wiki/Incandescent_light_bulb
but I haven't found an actual V vs I graph. I spose I could just take a
bulb and jot down some numbers, using a variac, eh?
Presumably a similar curve would arise from both AC and DC?
--
EA
heers!
> Rich
>
Josepi
We always laughed about the ones that didn't want to start, in those terms.
-----------
"Rich Grise" wrote in message
news:ilejbm$oqi$3...@news.eternal-september.org...
Josepi
as, as Rich so graciously pointed out, "the resistance goes up as the
temperature_"
Perhaps lamp manufacturer sites?
"Existential Angst" wrote in message
news:4d7b307a$0$5155$607e...@cv.net...
Does anyone know what this curve looks like? I would actually like a V vs.
I curve for a typical incandescant.
Googled some, wiki has an inneresting table on incandescant efficiency
http://en.wikipedia.org/wiki/Incandescent_light_bulb
but I haven't found an actual V vs I graph. I spose I could just take a
bulb and jot down some numbers, using a variac, eh?
Presumably a similar curve would arise from both AC and DC?
"Rich Grise" <ri...@example.net.invalid> wrote in message
news:ilej90$oqi$2...@news.eternal-september.org...
Just a nitpick, but technically, the resistance goes up as the
temperature_
increases. :-)
Michael A. Terrell
That would give you the data for that one bulb. There are
manufacturing variations from lamp to lamp. For instance: HP used a
small lamp in their early audio generators to control the gain. They
had to be hand selected to get the lowest distortion in each generator.
Winston
(...)
> Does anyone know what this curve looks like? I would actually like a V vs.
> I curve for a typical incandescant.
> Googled some, wiki has an inneresting table on incandescant efficiency
> http://en.wikipedia.org/wiki/Incandescent_light_bulb
>
> but I haven't found an actual V vs I graph. I spose I could just take a
> bulb and jot down some numbers, using a variac, eh?
>
> Presumably a similar curve would arise from both AC and DC?
From the context of the conversation, I assume that your
goal is to use an incandescent bulb as a voltmeter.
Is that correct, PV?
--Winston
Don Foreman
Yep. Those were called "barreters". They were in the feedback loop of
a Wein bridge oscillator. As the amplitude of the signal grew, so did
the resistance until the loop gain became exactly 1 and amplitude
stabilized at a steady-state value.
Michael A. Terrell
I have a TS-382F I am rebuilding. It is a military version of the
early HP 200 series, with the addition of a frequency meter. All the
'bathtub' capacitors are leaky, and a few 2W 5% resistors are burnt.
All metal tubes in the 'Wein bridge' and output amp.
Existential Angst
Close.... as a wattmeter..... :)
I monitor the voltage, and based on the applied voltage, impute power. But
I need to know resistance as a function of V, which a V vs I curve would
yield.
In the other thread I started specifically on this question, it seems the
data/links others provided will provide this.
Iow, if you have a 60 W bulb glowing away at 120 V (its rated voltage), you
know it's drawing 60 W.
But what if the voltage is 100? or 75? or 150?
--
EA, the result of being chronically PV'd
>
> --Winston
Robert Nichols
http://lmgtfy.com/?q=tungsten+filament+resistance
The second hit is a document with a diagram showing typical current vs.
voltage for input voltages from 50% to 150% of normal. It shows that at
50% voltage the lamp draws 69% of normal current, so the power would be
34.5%, rather than the 25% you would get for a fixed resistance. For
V=150% the current is 125%, yielding 187.5% of the nominal power.
--
Bob Nichols AT comcast.net I am "RNichols42"
Lewis Hartswick
>> That would give you the data for that one bulb. There are
>> manufacturing variations from lamp to lamp. For instance: HP used a
>> small lamp in their early audio generators to control the gain. They
>> had to be hand selected to get the lowest distortion in each generator.
>
> Yep. Those were called "barreters". They were in the feedback loop of
> a Wein bridge oscillator. As the amplitude of the signal grew, so did
> the resistance until the loop gain became exactly 1 and amplitude
> stabilized at a steady-state value.
Yep even Heath Kit used the same thing. I built a number of
them for the Coyne Radio and TV school in 1950 after I
graduated there I worked for the school for about 6 months.
Of course the 7 1/2 W bulbs were just the ordinary "nite
light" bulbs but they worked just fine.
Havent heard (or read) that term "Wein Bridge" for a very
LOOOOOOOONG time. :-)
...lew...
Josepi
read the voltage on the bulb. The long life units are sometimes rated at 130
volts and the cheap one at 115 volts and 117 volts. Some may be 110 volts
depending where they are manufactured. The Chinese think we are all short
and short on voltage too....LOL
I am not sure I would go by the rating of the bulb unless 10% error is a
good tolerence.
Are we pushing your accuracy requirements to new heights or what?....LOL
------------------
"Existential Angst" wrote in message
news:4d7c42c2$0$10371$607e...@cv.net...
Josepi
According to the second link the current curve is not perfectly linear but
very close by the few specimens I checked.
Buggers used a log scale one direction though. GRRRRRR...
Anybody scratch their LCD screen with a metal ruler?
----------------------
"Robert Nichols" wrote in message news:ilifi4$29i$1...@omega-3a.local...
Winston
> "Winston"<Win...@BigBrother.net> wrote in message
> news:ilg66...@news3.newsguy.com...
(...)
>> From the context of the conversation, I assume that your
>> goal is to use an incandescent bulb as a voltmeter.
>>
>> Is that correct, PV?
>
> Close.... as a wattmeter..... :)
> I monitor the voltage, and based on the applied voltage, impute power. But
> I need to know resistance as a function of V, which a V vs I curve would
> yield.
Why not use a nice, linear Hall Effect current sensor?
ACS758ECB-200B-PSS-T
This one acts like a 10 milliohm sense resistor but offers only 100
micro ohms of actual resistance to your circuit.
-Requires only a small DC power supply and a couple
reference resistors to sense up to +-200 A with your
multimeter.
http://www.allegromicro.com/en/Products/Categories/Sensors/currentsensor.asp
I've used these and they work a treat.
--Winston
Michael A. Terrell
Josepi wrote:
>
> Just to complicate things,
> read the voltage on the bulb. The long life units are sometimes rated at 130
> volts and the cheap one at 115 volts and 117 volts. Some may be 110 volts
> depending where they are manufactured. The Chinese think we are all short
> and short on voltage too....LOL
I've seen plenty of Chinese bulbs marked for 130 volts.
Josepi
There are no light bulbs made in N.America.
Secondly
They are commonly used for rural applications and exit sign where voltage
surges are common and long life is desired, respectively.
----------------------
"Michael A. Terrell" wrote in message
news:xZednT2Hm85WD-DQ...@earthlink.com...
I've seen plenty of Chinese bulbs marked for 130 volts.
---------------
Josepi wrote:
Just to complicate things,
read the voltage on the bulb. The long life units are sometimes rated at 130
volts and the cheap one at 115 volts and 117 volts. Some may be 110 volts
depending where they are manufactured. The Chinese think we are all short
and short on voltage too....LOL
.