Running a 1/4 hp 220 VAC condenser fan motor on 110 VAC
s...@aaronj.com
job, it would be preferable to run it this way.
Should I be concerned about overheating? Fire? Fuse protection?
It is located in the attic and if there is any doubt in using 110 VACI
can easily hook it to 220 VAC.
The fan is not being used for a condenser. I am using the fan for an
attic exhaust with the shaft horizontal.
The bearing will be lubed once a year with WD 20.
This is an interesting experiment.
The fan is blowing the air from the attic of one side of a duplex into
the other side.
The supply air is coming from one side from the soffit vents and
exhausted out the other side.
Hopefully this will cool both attics and cut down the electric bill.
It seems to be doing the job quite nicely.
Advice, comments?
.p.jm@see_my_sig_for_address.com
>On 110 VAC it starts easily and runs quietly. Assuming it does the
>job, it would be preferable to run it this way.
>
>Should I be concerned about overheating? Fire? Fuse protection?
Oh, hell, no. Just go right ahead and apply voltage to a
piece of equipment it was never designed to run on, it'll be OK.
>It is located in the attic and if there is any doubt in using 110 VACI
>can easily hook it to 220 VAC.
Naaaahhhhhh ! Too easy !
>
>The fan is not being used for a condenser. I am using the fan for an
>attic exhaust with the shaft horizontal.
>
>The bearing will be lubed once a year with WD 20.
>
>This is an interesting experiment.
>
>The fan is blowing the air from the attic of one side of a duplex into
>the other side.
>
>The supply air is coming from one side from the soffit vents and
>exhausted out the other side.
>
>Hopefully this will cool both attics and cut down the electric bill.
>It seems to be doing the job quite nicely.
>
>Advice, comments?
You're an idiot.
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Noon-Air
<s...@aaronj.com> wrote in message
news:1160318526.4...@k70g2000cwa.googlegroups.com...
You can *DO* what you want, but there is a reason motors are rated for
specific voltages, amps, and RPM.
I don't design them, so I defer to the data plates, as you should probably
do.
Mo Hoaner
I think his post to the group got delayed because I found a picture of his
house online already....
http://www.islandgazette.net/photo/pictures/images472004/P1010030.jpg
Here's yet another "interesting experiment" for him to try after he rebuilds
the duplex....
http://www.zellersys.com/S1_Rewire/S1%20Wiring%20Project.htm
Oscar_Lives
You got fire insurance, correct?
Any children or elderly living in the units?
(What a dope.)
DIMwit
a 220v ac motor is designed to operate at 220v not 115 volts. Believe it or
not, operating that motor at 115 will most likely draw too much current and
make the motor overheat. The exhaust air going over it to cool it may help,
but it is dead wrong to run it at 115volts.
The motor will try to run at its normal RPM, a factor of 60Hz and the number
of poles the motor is wound for. Lets say it is a 2 pole motor; at 60 Hz,
even though this is not made to be a synchronous motor, it will try to run
at 3600 RPM.
It will more like run at and be rated at 3450 RPM or so due to normal "slip"
at 230 volt operation. That will draw a certain current at 230 volts with
the load. And, we are not even talking about the same load here.
1)When you try to run it at 115 volts, using the same load, it will try to
achieve the same RPM, and at 115 volts, that RPM will require double the
amps (sound strange, but true). If the windings heat up beyond the
insulation class rating of the motor, it will burn up.
2) AC motors and transformers and other wound devices have inductive
reactance which causes its impedance to the flow of AC current to be much,
much lower than the DC resistance you would measure with an ohmmeter. The
motors are designed to present this impedance to the flow of current at
specific voltages that get the magnetic core at saturation design values.
Operation at 115 volts will most likely not achieve this, and the motor may
appear to be closer to the DC winding resistance value and draw lots of
current converted into heat unless that saturation point is reached, but it
will not be.
Those items 1 and 2 will try to make your motor fail and possible cause a
tragedy in your life. It is not worth the experiment. Buy a unit designed to
do what you need and run on 115v. I can't say it would be OK to run your
setup at 230 volts either. Would your insurance company??
Using WD40 as a lubricant (WD20??) is not an ideal motor lubricant.
I have oversimplified the technical aspects of the motor, but I believe it
to be pretty accurate as far as I went with it. Don't leave it running!
You have been warned by many already.
Bob
s...@aaronj.com
Bob,
FYI
http://www.wd40.com/Brands/3in1_product_info.html
Blue can: "It is a special blend of high-grade oils, equivalent to SAE
20. Its formulation is ideal for lubricating moving parts of electrical
motors. "
( I meant to write SAE 20.)
I agree that running a 220 VAC motor with a run capacitor will draw
more current proportionally then halving the voltage.
In a fan situation, the moving air will help.
After running for 9 hours, this motor did not overheat.
However, I will take you advice, and increase the voltage to 220 VAC.
Thanks
-zero
<s...@aaronj.com> wrote in message
news:1160397372....@h48g2000cwc.googlegroups.com...
>
>> Using WD40 as a lubricant (WD20??) is not an ideal motor lubricant.
>>
>
> Bob,
>
> FYI
>
> http://www.wd40.com/Brands/3in1_product_info.html
> Blue can: "It is a special blend of high-grade oils, equivalent to SAE
> 20. Its formulation is ideal for lubricating moving parts of electrical
> motors. "
> ( I meant to write SAE 20.)
So you fuck-up your facts, then turn and give him
your "FYI-Allow me correct you" bullshit! What an ass.
WD-40, is WD-40.
3-in-1 oil, is 3-in-1 oil.
SAE-20 has two flavors. Try not to pick the wrong one.
> I agree that running a 220 VAC motor with a run capacitor will draw
> more current proportionally then halving the voltage.
>
> In a fan situation, the moving air will help.
>
> After running for 9 hours, this motor did not overheat.
>
> However, I will take you advice, and increase the voltage to 220 VAC.
Yea, it's just one mans advice. He just made that up through the years.
It's just his opinion. How very graceful of you to put aside your
all-knowing wisdom and apply his "advice". That's lovely!
Every time you ask a question to anyone, there first response must be
"are you asking me or are you telling me?"
Stormy, will you please try to straighten this guy out!
DIMwit
I was only trying to keep Stu from harm. When I think I can help somebody
with what I do know, then I offer my help.
I do telephone tech support all day long on electrical/electronic machine
controls, so I am used to people telling me many things. I have to sort all
that out to figure out how to help them.
Regards,
Bob
"-zero" <notreal_zero_@notreal_zero_.com> wrote in message
news:yPvWg.2511$Tq3....@tornado.tampabay.rr.com...
Tekkie®
> Thanks for the support Zero.
>
> I was only trying to keep Stu from harm. When I think I can help somebody
> with what I do know, then I offer my help.
>
> I do telephone tech support all day long on electrical/electronic machine
> controls, so I am used to people telling me many things. I have to sort all
> that out to figure out how to help them.
>
> Regards,
>
> Bob
>
Don't top post!
Anyway let them talk until they stop. Ask a question and wait till they stop.
Ask another question and so on. When they utter very few words they are worn
out and receptive to what you ask and answers you give. Then they will either
do what you want or do what they want; therefore they go on the defective list.
Everyone has a story that they must unload before progress can be made...
--
Tekkie "There's no such thing as a tool I don't need."
Oscar_Lives
"Tekkie®" <Tek...@comcast.net> wrote in message
news:07adnYjgtNvUf7fY...@comcast.com...
How true! I unloaded a while ago, and now I feel like progressing...
DIMwit
"Oscar_Lives" <nos...@nospam.net> wrote in message
news:msEWg.1016517$084.197147@attbi_s22...
Charmin
s...@aaronj.com
Bull!
Heinz Ketchup, is Heinz pickles?
3-in-1 is a BRAND and not a product.
If you had taken 10 seconds to click on the link provided, you would
have learned about the many 3-in-1 products.
Question: Have you or any of your associates ever seen a 1/4 HP run
capacitor fan burn up and catch on fire on 110 VAC?
On another forum I have spoke to others who ran their 220 VAC motors
for years. One guy ran them in a main frame computer room and the
other in his attic. Both for years!
-zero
<s...@aaronj.com> wrote in message
news:1160506408.4...@i42g2000cwa.googlegroups.com...
> "3-in-1 oil, is 3-in-1 oil."
>
> Bull!
>
>
> Heinz Ketchup, is Heinz pickles?
>
> 3-in-1 is a BRAND and not a product.
>
>
> If you had taken 10 seconds to click on the link provided, you would
> have learned about the many 3-in-1 products.
What... Another attempt at deflection gone awry?
Didn't like your inadequacies made so openly transparent?
Just,,, calm down, you'll be fine.
> Question: Have you or any of your associates ever seen a 1/4 HP run
> capacitor fan burn up and catch on fire on 110 VAC?
If I told you YES, would you really believe me or really give-a-shit?
"YES" is not what you want to hear, anyway. So wire it up.
> On another forum I have spoke to others who ran their 220 VAC motors
> for years. One guy ran them in a main frame computer room and the
> other in his attic. Both for years!
And you need positive reinforcement from strangers to move
forward on your little project. That's wonderful.
Wire it up and turn the switch already!
-zero
Bob_Loblaw
We're trying to find a brain for Dildo!
--
Respectfully, Bob
DIMwit
validation. I hope not to read about you in the news.
I am an electrician, not a HVAC tech. I told you what you need to know; the
techs told you not to do what you did.
You can fry your food in 3 in 1 oil too if you want; maybe it won't hurt
your giblets. why don't you try it and let us know.
there's lots of idiotic things people do and get away with until one day: a
Darwin award is presented. http://www.darwinawards.com/
Life is scary enough without looking for trouble. Maybe you're a tough gang
member who fears nothing?
Dimwit
<s...@aaronj.com> wrote in message
news:1160506408.4...@i42g2000cwa.googlegroups.com...
s...@aaronj.com
DIMwit wrote:
> Damn you idiot fool! do what the hell you want and stop looking for
> validation. I hope not to read about you in the news.
>
> I am an electrician, not a HVAC tech. I told you what you need to know; the
> techs told you not to do what you did.
>
> You can fry your food in 3 in 1 oil too if you want; maybe it won't hurt
> your giblets. why don't you try it and let us know.
>
> there's lots of idiotic things people do and get away with until one day: a
> Darwin award is presented. http://www.darwinawards.com/
>
> Life is scary enough without looking for trouble. Maybe you're a tough gang
> member who fears nothing?
>
> Dimwit
>
> <s...@aaronj.com> wrote in message
Only words, zero data.
You guys are the urban myth!
Any facts?
.p.jm@see_my_sig_for_address.com
>
>DIMwit wrote:
>> Damn you idiot fool! do what the hell you want and stop looking for
>> validation. I hope not to read about you in the news.
>>
>> I am an electrician, not a HVAC tech. I told you what you need to know; the
>> techs told you not to do what you did.
>>
>> You can fry your food in 3 in 1 oil too if you want; maybe it won't hurt
>> your giblets. why don't you try it and let us know.
>>
>> there's lots of idiotic things people do and get away with until one day: a
>> Darwin award is presented. http://www.darwinawards.com/
>>
>> Life is scary enough without looking for trouble. Maybe you're a tough gang
>> member who fears nothing?
>>
>> Dimwit
>>
>> <s...@aaronj.com> wrote in message
>
>
>Only words, zero data.
>
>
>You guys are the urban myth!
Yes, we are.
So stop wasting your precious time with us myths and go hook
your motor up any way you please. No one here fucking cares.
We mythed it.
s...@aaronj.com
"Running the motor at half voltage shouldn't pose a problem. 30 years
ago we
frequently did this to fan motors that were used in computer mainframes
when
it wasn't necessary to provide full cooling capacity and we never had a
problem with them. If the fan moves enough air to satisfy you, then
there
shouldn't be an electrical problem with it. The bearings, however, may
fail
after a few years of use because they were really designed to be used
with
the shaft in a vertical plane and not designed to handle a significant
side
load. "
This is an "expert" validation, not an opinion.
The naysayers are label readers with zero experiece outside the box.
Again: Have you EVER seen an AC fan burnt out running on half voltage?
One?
"(and we never had a problem with them)"
.p.jm@see_my_sig_for_address.com
>
>"Running the motor at half voltage shouldn't pose a problem. 30 years
>ago we
>frequently did this to fan motors that were used in computer mainframes
>when
>it wasn't necessary to provide full cooling capacity and we never had a
>
>problem with them. If the fan moves enough air to satisfy you, then
>there
>shouldn't be an electrical problem with it. The bearings, however, may
>fail
>after a few years of use because they were really designed to be used
>with
>the shaft in a vertical plane and not designed to handle a significant
>side
>load. "
>
>This is an "expert" validation, not an opinion.
>
>
>The naysayers are label readers with zero experiece outside the box.
Which apparently exceeds your own 'knowledge' by a
considerable margin.
Why don't you just STFU and leave ? Why waste your oh so
precious time with us idiots ? Just fuckin go. Now.
>
>Again: Have you EVER seen an AC fan burnt out running on half voltage?
> One?
>
>"(and we never had a problem with them)"
--
Jake
> tragedy in your life. It is not worth the experiment. Buy a unit designed to
> do what you need and run on 115v. I can't say it would be OK to run your
> setup at 230 volts either. Would your insurance company??
Good explanations... and here's another:
In the motor world, torque (rotational force) is at least as important
as speed.
A common formula is that torque changes as the square of voltage applied.
Let's take a look at this application...
A motor rated at 220 volts.. and has 120 applied. That's 54.5 percent of
design voltage... so
.54 x .54 = 29.16
A motor wired like this will only produce 29.16 percent of its rated
torque. A one horespower motor would deliver less than 1/3 hp.
Besides being extremely inefficient, as Dimwit described (heat instead
of rotating force)... if the thing is moving any air at all it will be
overloaded more than 200 percent.
And it will fail... quickly... and with a lot of heat.. maybe smoke...
maybe fire. It's pure math.
> Using WD40 as a lubricant (WD20??) is not an ideal motor lubricant.
In fact, it's a awful motor lubricant. WD-40 is also a degreaser which
will frequently eat the insulation off motor windings, and quickly ruin
seals.
Spray Away!!!
Jake
Tekkie®
> We mythed it.
>
We won't myth Stu...
DIMwit
<s...@aaronj.com> wrote in message
news:1160520515.6...@b28g2000cwb.googlegroups.com...
>
> "Running the motor at half voltage shouldn't pose a problem. 30 years
> ago we
> frequently did this to fan motors that were used in computer mainframes
> when
> it wasn't necessary to provide full cooling capacity and we never had a
>
> problem with them. If the fan moves enough air to satisfy you, then
> there
> shouldn't be an electrical problem with it. The bearings, however, may
> fail
> after a few years of use because they were really designed to be used
> with
> the shaft in a vertical plane and not designed to handle a significant
> side
> load. "
>
> This is an "expert" validation, not an opinion.
Who was the expert you qoute?
I never stuck an M80 up my ass either, but I am very sure It would be a
disaster if I did and lit it. 0 experience on that, but an expert never
the less.
>
>
> The naysayers are label readers with zero experiece outside the box.
>
> Again: Have you EVER seen an AC fan burnt out running on half voltage?
> One?
>
> "(and we never had a problem with them)"
No, I never saw one burn up, cause I never tried to be cheap and cool my
house with a junk box spare part.
I have seen people smoking while they fuel their cars, but never saw one go
up in flames. That is not to say it never happens either.
enjoy you(r) barbeque after you relish the electric bill savings and not
having to buy the correct part.
by the way, if you were so sure you were right from the get go, why did you
ask anybody?
Are you a dentist? dentists are the cheapest bastards I have EVER met.
DIMwit
"Jake" <jkel...@insightbb.com> wrote in message
news:YMidnUmUNt0BtLHY...@insightbb.com...
Good added explanation Jake! A fan load is an easy starting load for the
motor, but as soon as (if) it gets up to any speed, it will be a big burden
on an under nourished motor. I don't know how much HP or fractional HP HIS
fan blade puts on a motor at xxxx RPM, but apparently Stu does.
My words re: WD40 were tongue in cheek, as most of know that WD40 is just as
you described. I use WD40 to clean and unstick things.
Must be Stu's simple desire to show us all up that he can. Maybe he should
call Guinness up
That's it for me on this topic, I hope.
Bob
Stormin Mormon
--
Christopher A. Young
You can't shout down a troll.
You have to starve them.
.
"Bob_Loblaw" <inocent...@hotmail.com> wrote in message
news:GCUWg.110493$ED.7...@read2.cgocable.net...
Stormin Mormon
--
Christopher A. Young
You can't shout down a troll.
You have to starve them.
.
"-zero" <notreal_zero_@notreal_zero_.com> wrote in message
news:yPvWg.2511$Tq3....@tornado.tampabay.rr.com...
s...@aaronj.com
of rotating force)... if the thing is moving any air at all it will be
overloaded more than 200 percent.
Where does 200% come from?
What does "200% overloading" mean with respect to temperatre gain?
What will be the rotational speed and what will the back EMF
(impedence) be as result from half voltage?
.p.jm@see_my_sig_for_address.com
Why would you ask such a bunch of lusers as you have declared
us to be ?
Why dont' you shove it straight up your ass, and impedance be
damned ?
DIMwit
<s...@aaronj.com> wrote in message
news:1160535937.6...@i3g2000cwc.googlegroups.com...
how fast will your car go up a big hill if you take out half the spark
plugs? how big is the hill? You are also posting Jake's valid statements as
my words.
why continue any further? do what you want.
I admit I am a fraud. I am a circus clown who stayed at a Holiday Inn
Express and thought I could spew some idiotic nonsense, but you win! you
exposed me for what I am. Now go away and let me wallow in my misery. You
can now rest easy and cool with your experiment.
Boo Hoo, fuck you
Noon-Air
<s...@aaronj.com> wrote in message
news:1160535937.6...@i3g2000cwc.googlegroups.com...
So, just exactly what class are you taking and where are you taking it?? Do
they know that your trying to get the folks on this NG to do your homework
for you??
Oscar_Lives
"DIMwit" <ig...@ignacious.com> wrote in message
news:vK3Xg.815$jj1...@newsfe08.lga...
>
> <s...@aaronj.com> wrote in message
> news:1160535937.6...@i3g2000cwc.googlegroups.com...
>> Besides being extremely inefficient, as Dimwit described (heat instead
>> of rotating force)... if the thing is moving any air at all it will be
>> overloaded more than 200 percent.
>>
>> Where does 200% come from?
>>
>> What does "200% overloading" mean with respect to temperatre gain?
>>
>>
>> What will be the rotational speed and what will the back EMF
>> (impedence) be as result from half voltage?
>
> how fast will your car go up a big hill if you take out half the spark
> plugs? how big is the hill? You are also posting Jake's valid statements
> as my words.
>
> why continue any further? do what you want.
>
> I admit I am a fraud. I am a circus clown who stayed at a Holiday Inn
> Express and thought I could spew some idiotic nonsense, but you win!
Hey, at least you got the cinnamon rolls!
s...@aaronj.com
You guys are something.
Ask a factual question and your ignore it.
Attack, attack, but no factual data, explanation, or experience.
None!.
Is this the way that you live your life, in darkness and anger?
State a figure, 200% and the world is expecterd to accept it?
Where did you get it, out of your ass?
If I wanted to listen to an asshole, I could have farted.
Homework? You probably never did any.
.p.jm@see_my_sig_for_address.com
You did. We just don't understand why you did it here.
>
>
>Homework? You probably never did any.
--
s...@aaronj.com
Running at half voltage will not double the current consumption, it
will basically halve it, resulting in about 1/4 of the rated power.
A motor has a particular impedance seen "looking" into its cables.
This has nothing to do with the voltage you apply, but rather is a
function of the coils inside the motor. The motor isn't some magical
piece of machinery which draws constant power (wattage). It follows
Ohm's law: V=I*Z, where Z is the impedance. If you solve this
algebraically for the current I, you get I=V/Z. Since Z doesn't
change, the current drawn is directly proportional to the voltage
applied. Hence, half the voltage results in half the current.
I suppose I need to add an asterisk to this comment because motors are
somewhat unique. The impedance of the motor is dynamic; it gets much
higher as the motor spins up, because the mechanical motion of the
motor acts as a generator, essentially creating its own current to some
extent (usually called back-EMF). That's why motors draw a lot more
current upon startup and when they are heavily bogged down than when
they are running at full speed. Thus, since a motor running at half
voltage is likely going to be spinning more slowly than one at the full
rated voltage, it's dynamic impedance will be somewhat lower and it may
draw somewhat more than half the current, but definitely NOT twice the
current.
The applied voltage is the sum of IR drop and back emf.
(1) V = E + I R.
The back emf is proportional to the product of the magnetic field and
the
armature speed. Assuming a linear model for the field
(2) E = k1 * I * w.
The torque is proportional to the field current and the armature
current which
are equal.
(3) T = k2 * I^2.
>From (1) and (2) we get
(4) I = V / (k1 * w + R).
>From (3) and (4)
(5) T = k2 * [V / (k1 * w + R)]^2.
Solve for the speed to get
(6) w = k * V / sqrt(T) - c * R
where k and c are constants related to k1 and k2.
>From this, you can estimate torque for a blocked armature. Similarly,
you can
see that the model breaks down at zero torque (runaway). In many
situations,
you can neglect the R term to get an approximation
(7) w = k * V / sqrt(T).
Thus, for a constant torque load, cutting the voltage in half will cut
the
speed in half.
I have experience with permanent magnet DC motors like golf cart
motors.
Double the voltage and you double the current and the rpm.
Most homebuilt electric auto conversions use 2,3, and 4 times the
voltage in their cars.
For example a 12 Volt motor running at 48 Volts.
With 4 x the current, these motors run for years.
(Read any electric car group to verify this.)
Back to an Induction motor. Halving the voltage will not double the
current.
The stress will be LESS than tripling the voltage on a DC motor.
Just my $0.02 and years of experience.
s...@aaronj.com
--------------------------------------
I have experience with permanent magnet DC motors of the type used in
golf carts etc.
Double the voltage and you double the current and the rpm.
Most homebuilt electric auto conversions use 2,3, and 4 times the
voltage in their cars.
For example a 24 Volt motor running at 96 Volts.
.p.jm@see_my_sig_for_address.com
( snip a complete bunch of bullshit regarding how AC motors work )
Do you by any chancce design missiles and nukes for North
Korea in your spare time ?
Jake
You obviously have no understanding of electrical theory or induction
motors or Alternating Current.
Here's a good start...
http://www.maintenanceworld.com/Articles/reliance/maintenance.htm
Remember, 'Induction Motors' are inductive loads... which are much
different animals than 'resistive loads'.
Now, to Ohms law. I=E/R. Let's try it...
We have a single phase motor with 20 Ohms resistance across its STATOR.
By the way, the rotating element in a AC motor is called a rotor and not
an armature. There are reasons for this... Google it.
Anyhow... now we have part of the formula.... R. Now let's try E.
E would be either 120 volts or 240 volts in your example... so...
I=120/20 or I = 6
AND
I= 240/20 or I = 12
Oh Darn.... it seems you're right... the motor will draw TWICE as much
current at 240 volts...
Or will it...?
We kind of forgot about the other 'relationships' in Ohms law... like
where R=E/I...
See... they're all 'related' to one another. Resistance drops in
relation to Voltage.. quite dramatically.
Play with this exercise for a while and get back to us.
http://jersey.uoregon.edu/vlab/Voltage/
Jake
s...@aaronj.com
Jake,
I agree with your example for a static situation
However in an induction motoras the rpm increase there is a generated
back EMF which "bucks" the current and therefore at 220 VAC the current
is less than 220/20.
The back EMF is reduced as the rpm is reduced.
Let's say that for an induction motor at 1,000 rpm with 220 VAC
instead of the expected 12 amps of current we measure 6 amps. This is
the equivalent of reducing the 220 VAC to an applied 110 VAC for a
resistive load. Power input would be 220 x 6 = 1320 Watts.
Drop the applied voltage to 120 VAC and we would expect the motor to
run at about 500 rpm.
Of course there is some back EMF, but let's ignore it.
Would we not expect to measure 120/20 = 6 amps?
The same 6 AMP current used at 220 VAC?
We would be using 6 x 120 = 720 Watts for half the rpm and half the
CFM.
Please correct me if my assumptions are wrong.
s...@aaronj.com
Jake,
I agree with your example for a static situation
However in an induction motoras the rpm increase there is a generated
back EMF which "bucks" the current and therefore at 220 VAC the current
is less than 220/20.
The back EMF is reduced as the rpm is reduced.
Let's say that for an induction motor at 1,000 rpm with 220 VAC
instead of the expected 12 amps of current we measure 6 amps. This is
the equivalent of reducing the 220 VAC to an applied 110 VAC for a
resistive load. Power would be 220 x 6 = 1320 Watts.
Drop the applied voltage to 120 VAC and we would expect the motor to
run at 500 rpm.
Of course there is some back EMF, but let's ignore it.
Would we not expect to measure 120/20 = 6 amps?
The same current used at 220 VAC?
DIMwit
Why bother, Jake? he asked a stupid question in his first post, now he knows
it all. He may know DC motors ( I know them very well myself). where things
are quite linear, but AC motors are somewhat more complex. Ohm's law is only
a very small consideration in calculating the AC current.
Here is an excellent example of what goes on. use the Java applet to see
where the current goes as you adjust the voltage. This does not show how any
winding is rated for a particular voltage, but it can be seen that there is
a voltage point that the current is minimum at and increasing or decreasing
the voltage from that point causes substantial current increase. amazing
Stu?
http://www.ndt-ed.org/EducationResources/CommunityCollege/EddyCurrents/Physics/impedance.htm
Bob
Oscar_Lives
<s...@aaronj.com> wrote in message
news:1160609240....@k70g2000cwa.googlegroups.com...
Do you fucking have any idea who you are talking to?
The only thing for you to do right now is hang your head in deep shame and
sit quietly and LISTEN and LEARN.
Woe be to thee...
Jake
>
> Please correct me if my assumptions are wrong.
>
They are wrong because you're still stuck on DC.
An Alternating Current AC induction motor MUST run at line frequency
(its wound RPM) or 'slip' is introduced that causes all kinds of havoc.
Here's a decent web article:
http://www.electricmotors.machinedesign.com/guiEdits/Content/bdeee2/bdeee2_1.aspx
DC motors were commonly used in industry for many years because speed
and torque could be easily controlled... not something that was possible
before electronics allowed us to vary 'line frequency' in order to
change AC motor speeds.
Today, we change the speed of AC motors through the use of VFD's... or
Variable Frequency Drives. They basically change the frequency of AC
(how quickly the alternating current changes polarities) anywhere from
-zero- to whatever the motor can handle. Standard 'from your socket' is
60 hertz... meaning the polarity changes 60 times a second... or 120
times from PLUS to MINUS. VFD's can change this in a range from ZERO...
holding the motor at a dead stop (brake) to running many thousands of
RPM's. There's lots of nifty new technology like DC braking, and DC
injection for startup, to vector control.. on and on.
Point is... unless you change the frequency of an AC supply... the motor
must run at speed or it will fail. If something like a low voltage or
heavy mechanical load slows it down... it will not be able to deliver
the induced magnetic field into the rotor and thus heat builds in the
stator... causing failure or fire.
Look at the Reliance link again... great info for beginners there...
Jake
DIMwit
<s...@aaronj.com> wrote in message
news:1160582931....@h48g2000cwc.googlegroups.com...
Ahem, years of experience? 2 days ago you asked a newbie question. You have
matured quite rapidly. You now need to know AC motors, being you are the DC
motor expert here. (oh I may be too, but too humble to claim being an
expert).
Running a 24 volt dc motor at 96 volts will make the motor run at 4 times
its rated RPM, and if it is not built to run that fast will be destroyed by
centrifugal force, by the way.
Now run along and read some more and be an AC expert in a day or 2.
you must have a real high IQ, being able to learn so fast. Took me a few
years, but that's why I call myself Dimwit. Funny think is, people call me
for help, and I do help them. Can't figure that out either.
Oh well
DIMwit
<s...@aaronj.com> wrote in message
news:1160571303.9...@e3g2000cwe.googlegroups.com...
If you wanted to listen to an asshole, you would not have far to go,
methinks. very short distance
.p.jm@see_my_sig_for_address.com
wrote:
Oh, that one's gonna leave a mark :-)
>
>Jake
Bubba
See Jake,
You got it alllllllllllllllllll wrong. You completly forgot about the
"bucking"..............bahahahahahahaha
Somebody, PLEASEEEEEEEEEEEEEEEEEEEEE shoot this critter and get him
outta here. I cant take the pain much longer. :-)
Bubba
s...@aaronj.com
motor
must run at speed or it will fail. If something like a low voltage or
heavy mechanical load slows it down... it will not be able to deliver
the induced magnetic field into the rotor and thus heat builds in the
stator... causing failure or fire. "
Is the is statement of yours absolute?
Are you saying that in zero cases an induction motor will not run a
long time at reduced rpm on half voltage?
There are many, many examples of where people used half voltage on FAN
motors in order to reduce FAN noise.
Wanna bet that this is not done successfully?
Perhaps the issue is one of cooling. A FAN motor cools itself.
Have you EVER seen a half voltage fan motor catch on fire?
""Running the motor at half voltage shouldn't pose a problem. 30 years
ago we
frequently did this to fan motors that were used in computer mainframes
when
it wasn't necessary to provide full cooling capacity and we never had a
problem with them.""
This guy is not lying. How do you explain it?
Tekkie®
>
> If I wanted to listen to an asshole, I could have talked more
>
--
Tekkie "There's no such thing as a tool I don't need."
Noon-Air
<s...@aaronj.com> wrote in message
news:1160571303.9...@e3g2000cwe.googlegroups.com...
I did enough homework to know the difference between a DC motor and an AC
PSC motor. If what your trying to feed us would actually work, I would only
have to carry ONE size/type motor on my truck instead of the 5 that I *DO*
carry.
After you let the factory smoke out of a few motors, then come back and
we'll chat.
Jake
> "Point is... unless you change the frequency of an AC supply... the
> motor
> must run at speed or it will fail. If something like a low voltage or
> heavy mechanical load slows it down... it will not be able to deliver
> the induced magnetic field into the rotor and thus heat builds in the
> stator... causing failure or fire. "
>
> Is the is statement of yours absolute?
>
Yes... it's pure physics. You're introducing voltage into a stationary
coil where it cannot be dissipated (unless the motor is turning at line
frequency). When the energy cannot be thrown into the rotor (and thus
mechanical energy) it creates heat... a lot of it.
For the third time... read the Reliance link. If you have questions from
it.. please ask. Otherwise... I'd done here.
> Are you saying that in zero cases an induction motor will not run a
> long time at reduced rpm on half voltage?
>
> There are many, many examples of where people used half voltage on FAN
> motors in order to reduce FAN noise.
>
> Wanna bet that this is not done successfully?
>
> Perhaps the issue is one of cooling. A FAN motor cools itself.
>
>
> Have you EVER seen a half voltage fan motor catch on fire?
I've never seen a half voltage fan motor even start to turn... Maybe...
if you put a little itty-bitty blade on it this is possible (for it turn
turn)... but not run all that long.
>
>
> ""Running the motor at half voltage shouldn't pose a problem. 30 years
> ago we
> frequently did this to fan motors that were used in computer mainframes
> when
> it wasn't necessary to provide full cooling capacity and we never had a
>
> problem with them.""
>
>
> This guy is not lying. How do you explain it?
>
Many old fans in mainframes were run off the DC buss. Maybe that's what
the guy is talking about here.
The fan on your computer now is not an AC fan. That's why the modern
Power supplies and motherboards can run at variable speeds.
Jake
s...@aaronj.com
>
> I did enough homework to know the difference between a DC motor and an AC
> PSC motor. If what your trying to feed us would actually work, I would only
> have to carry ONE size/type motor on my truck instead of the 5 that I *DO*
> carry.
Great! That is not the point. Your motors are each used for a
specific application.
You have not addressed the question, "can you use any one of your 5
220 AC motors at 110 VAC and will it start and run without burning up?
Take a fan from a pulled compresser and try it for a few hours.
The main difference between a dc and an ac motor that controls the
current is the back EMF. I call it the 'bucking' voltage because it is
just like using a transformer to reduce the applied voltage..
s...@aaronj.com
>From another forum:
"Technically speaking those fans are not guaranteed to even start at
115
VAC. Minimum operating is about 185 or so (I had problems downloading
the
PDFs so I couldn't get the exact specs and am going by general AC fan
characteristics). If they run it's okay but you should be aware that
some
time they might not (age, lubrication, dirt, etc. not to mention that
115
is nominal and can be even lower) and then you've got a locked rotor
situation where the current will shoot up (no back EMF from rotation).
They've probably got locked rotor current protection though so they
shouldn't do something drastic like catch fire."
Perhaps this is your implied caution?
s...@aaronj.com
alt.engineering.electrical
Depends on the fan motor really, I have run my furnace fan motor on
reduced voltage to keep air moving about the house and through the
electrostatic air cleaner. If its a belt drive affair I wouldnt run it
on 120v however most direct drive motors are series poled motors
meaning 6 or 8 poles are switched in and out for diffrent speeds eg 4
poles for 1750RPM no load speed.
Mine has been running on a switch relay for years switching to high
speed 240v for demand then switching one side down via SPDT relay and
moving one side down to neutral to slow the motor when the stack temp
drops below the cutoff point. Havnt replaced the motor yet in 17 years
now and I have been running the switching relay since I installed the
heating plant, only oil the bearings a little more often.
Word of caution: If its a capacitor start motor I wouldnt reduce the
voltage, the start winding will overheat.
-----------------------
I have a capacitor RUN motor not a capacitor START motor.
Comments?
Noon-Air
<s...@aaronj.com> wrote in message
news:1160653382....@m7g2000cwm.googlegroups.com...
>
>>
>> I did enough homework to know the difference between a DC motor and an AC
>> PSC motor. If what your trying to feed us would actually work, I would
>> only
>> have to carry ONE size/type motor on my truck instead of the 5 that I
>> *DO*
>> carry.
>
>
> Great! That is not the point. Your motors are each used for a
> specific application.
Exactly!!! You are trying to lump *ALL* motors in one big pile. Sure you can
run a DC motor at half voltage and it will run...granted with reduced
horsepower and higher amp draw, and a 240v PSC fan motor will run *briefly*
at 120v and 1/10 of its rated speed. Again, why would you want to do it ON
PURPOSE??
> You have not addressed the question, "can you use any one of your 5
> 220 AC motors at 110 VAC and will it start and run without burning up?
I wouldn't even think of trying to run a PSC motor at half voltage...why
would you want to?? its counter-productive, and not what the manufacturing
engineers designed it for.
> Take a fan from a pulled compresser and try it for a few hours.
A "compressor" doesn't have a fan.....a "condenser" does.
> The main difference between a dc and an ac motor that controls the
> current is the back EMF. I call it the 'bucking' voltage because it is
> just like using a transformer to reduce the applied voltage..
I'm not a motor design engineer, but I do know enough to know when somebody
is trying to feed me a Twinky filled with something I don't want to step in.
Sorry, I'm not bitin on it.
You never did answer my question.... what class are you taking that you need
this information??
s...@aaronj.com
Read the post from an electgrical engineer above your post.
He was talking about a 220 VAC motor. 17 YEARS enough proof?
A "compressor" is name of the box in which the compresser and the fan
is housed.
It is good the be exacting. (but I think you knew what I meant).
Bubba
To EVERYONE:
I think you can see from the line above that you are all dealing with
a retard. Now he wants to argue that an outdoor cooling unit is called
a compressor and not a condenser!!!
He has trolled here long enough.
Say goodbye to this Butt-Fuck.
Bubba
s...@aaronj.com
>
> To EVERYONE:
> I think you can see from the line above that you are all dealing with
> a retard. Now he wants to argue that an outdoor cooling unit is called
> a compressor and not a condenser!!!
> He has trolled here long enough.
> Say goodbye to this Butt-Fuck.
> Bubba
> >
> >It is good the be exacting. (but I think you knew what I meant).
Cooling unit?
Oh! The thing.
It doesn't matter if I called you a genius, you are the opposite.
Calling each other names is what this thread enjoys, not learning a
damn thing.....
DIMwit
<s...@aaronj.com> wrote in message
news:1160691686.5...@b28g2000cwb.googlegroups.com...
Noon-Air
<s...@aaronj.com> wrote in message
news:1160691686.5...@b28g2000cwb.googlegroups.com...
Learned that my killfile still works.....
*PLONK*
AKS
there for most of you are right but some of you are wrong
you don't bother reading between the lines "SMILE"
The motors as is been said that start with start capacitor
or centrifugal switch on primary wining CAN NOT BE USED
WITH REDUCE VOLTAGE, however the shaded pole
and multi-tap winnings that use running capacitor or with out
running capacitor CAN BE USE FROM APX. 20% of it's
rated voltage to a full rated voltage, and you can use some of
house light dimmers to control speed of the motor. the speed
will not be linear but it will work those are the facts I did it
and I have equipment that uses exact what I just describe.
I know some of you will disagreed don't blame me
because you lack experience.
Dido
"DIMwit" <ig...@ignacious.com> wrote in message
news:5gVWg.230$jj1...@newsfe08.lga...
> Damn you idiot fool! do what the hell you want and stop looking for
> validation. I hope not to read about you in the news.
>
> I am an electrician, not a HVAC tech. I told you what you need to know;
> the techs told you not to do what you did.
>
> You can fry your food in 3 in 1 oil too if you want; maybe it won't hurt
> your giblets. why don't you try it and let us know.
>
> there's lots of idiotic things people do and get away with until one day:
> a Darwin award is presented. http://www.darwinawards.com/
>
> Life is scary enough without looking for trouble. Maybe you're a tough
> gang member who fears nothing?
>
> Dimwit
>
> <s...@aaronj.com> wrote in message
> news:1160506408.4...@i42g2000cwa.googlegroups.com...
>> "3-in-1 oil, is 3-in-1 oil."
>>
>> Bull!
>>
>>
>> Heinz Ketchup, is Heinz pickles?
>>
>> 3-in-1 is a BRAND and not a product.
>>
>>
>> If you had taken 10 seconds to click on the link provided, you would
>> have learned about the many 3-in-1 products.
>>
>>
>> Question: Have you or any of your associates ever seen a 1/4 HP run
>> capacitor fan burn up and catch on fire on 110 VAC?
>>
>>
>> On another forum I have spoke to others who ran their 220 VAC motors
>> for years. One guy ran them in a main frame computer room and the
>> other in his attic. Both for years!
>>
>
>
Bubba
pints and maybe, just maybe in a few hours I will be able to figure
out just what the fuck that is that you typed down below.
Bubba
AKS
"Bubba" <LiKeAlA...@iname.com> wrote in message
news:s6oti2p39np92l8e3...@4ax.com...
Jake
> I will not quote any one of you some of you missing the point
> there for most of you are right but some of you are wrong
> you don't bother reading between the lines "SMILE"
> The motors as is been said that start with start capacitor
> or centrifugal switch on primary wining CAN NOT BE USED
> WITH REDUCE VOLTAGE, however the shaded pole
> and multi-tap winnings that use running capacitor or with out
> running capacitor CAN BE USE FROM APX. 20% of it's
> rated voltage to a full rated voltage, and you can use some of
> house light dimmers to control speed of the motor. the speed
> will not be linear but it will work those are the facts I did it
> and I have equipment that uses exact what I just describe.
> I know some of you will disagreed don't blame me
> because you lack experience.
> Dido
>
>
Look, Dido.... a quick inspection of NEMA and IEC specs say that most
motors are 'designed' for +/- 10 percent... that's all.
Anything more or less and the motor is running so out of sync with the
line that it builds heat rapidly. AC and motor theory are as clear as
they can be...
Heat kills motors... maybe not immediately but in short order.
Shaded pole motors are crap.. and if they're in anything you depend on
you ought to throw them away and use real motors. They're great in wall
clocks, though....
The back-emf argument is also bullshit. Back EMF is 'out-of-phase' and
counteracts the inputted energy. It hurts you.. not helps.
As with all things in the genre... energy IN equals energy OUT less
losses. If you put less energy IN... things don't work as designed.
Anything may work for a while... but not all that long. Science catches
up sooner or later.
Jake
Bob_Loblaw
> Hold on a minute Dildo. I gotta go grab a big ol LSD pill and a couple
> pints and maybe, just maybe in a few hours I will be able to figure
> out just what the fuck that is that you typed down below.
> Bubba
It still won't make any sense...trust me!
Respectfully, Bob
PrecisionMachinisT
"AKS" <a.s...@verizon.net> wrote in message
news:F9BXg.13270$2l5.4959@trnddc07...
> however the shaded pole
> and multi-tap winnings that use running capacitor or with out
> running capacitor CAN BE USE FROM APX. 20% of it's
> rated voltage to a full rated voltage, and you can use some of
> house light dimmers to control speed of the motor. the speed
> will not be linear but it will work those are the facts I did it
> and I have equipment that uses exact what I just describe.
> I know some of you will disagreed don't blame me
> because you lack experience.
>
Rpm will vary quite signifantly upon very small changes in shaft mechanical
load if you do as you state above.
--
SVL
PrecisionMachinisT
"Jake" <jkel...@insightbb.com> wrote in message
news:JYadnYQeC6jDG7DY...@insightbb.com...
>
> An Alternating Current AC induction motor MUST run at line frequency
> (its wound RPM) or 'slip' is introduced that causes all kinds of havoc.
>
Jake, max slippage occurs only under full output--only when unloaded do they
run synchronous with line frequency ( actually, slightly below--due to
frictional losses )....
Interesting way to look at this is to consider a motor that's wound for lets
say 2000 rpms and produces at fla 10hp with 10% slip....IOW, rated
1800rpms...
Now, if we instead were to drive this same motor shaft with a 10 hp prime
mover, at 2200rpms, while still leaving it connected to the mains....it
will backfeed at fla into the utility lines.
Much of this comes into play where you have medium scale grid connected
hydro or windpower systems, that sorta thing.
--
SVL
s...@aaronj.com
AKS wrote:
> I will not quote any one of you some of you missing the point
> there for most of you are right but some of you are wrong
> you don't bother reading between the lines "SMILE"
> The motors as is been said that start with start capacitor
> or centrifugal switch on primary wining CAN NOT BE USED
> WITH REDUCE VOLTAGE, however the shaded pole
> and multi-tap winnings that use running capacitor or with out
> running capacitor CAN BE USE FROM APX. 20% of it's
> rated voltage to a full rated voltage, and you can use some of
> house light dimmers to control speed of the motor. the speed
> will not be linear but it will work those are the facts I did it
> and I have equipment that uses exact what I just describe.
> I know some of you will disagreed don't blame me
> because you lack experience.
> Dido
>
>
AFAIK Every run start cap motors used for fans in condensers use
overload breakers to avoid locked rotor overheating. This is required
because foreign objects like twigs, rats, snakes, etc. can get into the
box and stop the fan blades.
If a 220 VAC motor will turn with 110 VAC applied, it should be safe
from overheating.
This has been done many, many times.
Some technicians do not understand the safety built into the motors.
As an additional safety, a second lower Amp fuse may be added.
Bubba
>
>AKS wrote:
>> I will not quote any one of you some of you missing the point
>> there for most of you are right but some of you are wrong
>> you don't bother reading between the lines "SMILE"
>> The motors as is been said that start with start capacitor
>> or centrifugal switch on primary wining CAN NOT BE USED
>> WITH REDUCE VOLTAGE, however the shaded pole
>> and multi-tap winnings that use running capacitor or with out
>> running capacitor CAN BE USE FROM APX. 20% of it's
>> rated voltage to a full rated voltage, and you can use some of
>> house light dimmers to control speed of the motor. the speed
>> will not be linear but it will work those are the facts I did it
>> and I have equipment that uses exact what I just describe.
>> I know some of you will disagreed don't blame me
>> because you lack experience.
>> Dido
>>
>>
>AKS,
>
>
>AFAIK Every run start cap motors used for fans in condensers use
>overload breakers to avoid locked rotor overheating.
Crimmany sakes! I knew you were dumber than a box of rocks.
Bubba
s...@aaronj.com
>
> Crimmany sakes! I knew you were dumber than a box of rocks.
> Bubba
>
Yes, about as dumb as the people who design and make the motors;
Reliance!
I guess that you can't trust their words either.
http://www.reliance.com/mtr/mtrthrmn.htm
"At the same time torque is being produced, the conductors are moving
in a magnetic field and generating a voltage. This voltage is in
opposition to the voltage that causes current flow through the
conductor and is referred to as a countervoltage or back EMF. The value
of current flowing through the armature is dependent upon the
DIFFERENCE between the applied voltage and the countervoltage."
The countervoltage or back EMF is opposite the applied voltage and it
therefore
"bucks" or reduces it. For example: If the applied voltage is 220
VAC and the back
EMF is 70 VAC, the motor appear to see only 150 VAC.
The result is the equivalent of increasing the total impedence and thus
reduces the current that
would flow if there was no EMF.
This is why an AC motor must spin to avoid overheating.
An automatic thermal overload protector is usually built into HVAC fan
motors.
Or, if you desire, you can always add a correctly chosen fuse to
protect your AC motor.
Bubba,
If you had another brain it would be lonesome.
AKS
> AKS wrote:
>> I will not quote any one of you some of you missing the point
>> there for most of you are right but some of you are wrong
>> you don't bother reading between the lines "SMILE"
>> The motors as is been said that start with start capacitor
>> or centrifugal switch on primary wining CAN NOT BE USED
>> WITH multi-tap winnings that use running capacitor or with out
>> running capacitor CAN BE USE FROM APX. 20% of it's
>> rated voltage to a full rated voltage, and you can use some of
>> house light dimmers to control speed of the motor. the speed
>> will not be linear but it will work those are the facts I did it
>> and I have equipment that uses exact what I just describe.
>> I know some of you will disagreed don't blame me
>> because you lack experience.
>> Dido
>>
>>
>
> Look, Dido.... a quick inspection of NEMA and IEC specs say that most
> motors are 'designed' for +/- 10 percent... that's all.
>
> Anything more or less and the motor is running so out of sync with the
> line that it builds heat rapidly. AC and motor theory are as clear as they
> can be...
>
> Heat kills motors... maybe not immediately but in short order.
>
> Shaded pole motors are crap.. and if they're in anything you depend on you
> ought to throw them away and use real motors. They're great in wall
> clocks, though....
>
> The back-emf argument is also bullshit. Back EMF is 'out-of-phase' and
> counteracts the inputted energy. It hurts you.. not helps.
>
> As with all things in the genre... energy IN equals energy OUT less
> losses. If you put less energy IN... things don't work as designed.
>
> Anything may work for a while... but not all that long. Science catches up
> sooner or later.
>
I posted what I work with the only thing I forgot to include that
these is only on single phase motors and dimmers that can be
use is only those that use triacs for output instead of SCRs
Dido
>
>
>
AKS
"PrecisionMachinisT" <Precision...@hotmail.com> wrote in message
news:egn600$1cml$1...@usenetserver.com...
AKS
> On 13 Oct 2006 05:29:39 -0700, s...@aaronj.com wrote:
>
>>
>>AKS wrote:
>>> I will not quote any one of you some of you missing the point
>>> there for most of you are right but some of you are wrong
>>> you don't bother reading between the lines "SMILE"
>>> The motors as is been said that start with start capacitor
>>> or centrifugal switch on primary wining CAN NOT BE USED
>>> WITH REDUCE VOLTAGE, however the shaded pole
>>> and multi-tap winnings that use running capacitor or with out
>>> running capacitor CAN BE USE FROM APX. 20% of it's
>>> rated voltage to a full rated voltage, and you can use some of
>>> house light dimmers to control speed of the motor. the speed
>>> will not be linear but it will work those are the facts I did it
>>> and I have equipment that uses exact what I just describe.
>>> I know some of you will disagreed don't blame me
>>> because you lack experience.
>>> Dido
>>>
>>>
>>AKS,
>>
>>
>>AFAIK Every run start cap motors used for fans in condensers use
>>overload breakers to avoid locked rotor overheating.
>
> Crimmany sakes! I knew you were dumber than a box of rocks.
Thanks Bubba that is why I get paid to travel up to 5 hours
in one direction and getting paid $135.00 per hour from shop
back to shop
Dido
AKS
"Bob_Loblaw" <inocent...@hotmail.com> wrote in message
news:CBEXg.167107$sS1....@read1.cgocable.net...
Sir you are big joke
Dido
Oscar_Lives
Dildo, please post again tomorrow when you are sober.
AKS
"Oscar_Lives" <nos...@nospam.net> wrote in message
news:mIYXg.238892$1i1.109769@attbi_s72...
Oscar get some experience and you bud! then talk
s...@aaronj.com
Physics Archive
Question - I am confused about the concept of 'back emf'.
Have you got a clear, concise and logical explanation of just what it
is?
------------------------------------------------
Hi, Ben !!
Well, as you probably already heard before, the back-emf is
the same as counter emf (cemf). It is a voltage produced in
a conductor that tends to neutralize the present voltage. It is
a phenomenon that always tends towards the contrary of what happens!!
Let´s suppose: if lines of a magnetic field are cut by a conductor,
than a voltage is generated in this conductor, which causes a
current of electrons to flow in one direction. At the same time,
like trying to avoid this, ANOTHER voltage is created that tends
to neutralize this effect, and it forces the electrons to flow in the
contrary direction. As you know, the back-emf is directly pro-
portional to the velocity of the magnetic field. It is proportional
to the relative motion between them.
I am sure that you know all of this. But, to give you an example,
think of a wire with a switch. Suppose the electrons are running
from a direction into another and suddenly, you open the switch.
What happens?? Well, when electrons run, they give rise to a magnetic
field. When you open the switch, the electrons should stop their
flow. But - as a kind of inertial action - they try to continue the
flow,
and ionize the air, in an electric arc to find its way. Or let it be,
the originally initial magnetic field, in a circumference around
the wire, changes its sense, and try to avoid stopping the original
flow. It is possible to see this in an oscilloscope, as a negative
peak in certain experiences where you make use of a coil and
- abruptely - stops the electron flow.
I know you know all of this. But, that is it!!! It is the way things
are.
Just try to answer this question: what is electrical charge?
Why is that we have positive and negative charges?? Answer :
nobody knows it!!! We must accept this condition!!! It belongs
to the laws of the universe, since the big bang created it like as it
is.
Just to speak a little bit more about this subject, you know that
when an electrical induction "squirrel" motor runs, you have a
magnetic field that circulates around the squirrel. There is a
speed difference between them, what in turn generates a voltage
and a force appears, which drives the "squirrel". A back-emf
also appears, which lowers the net electric electron flow. The
current through a rotating electric motor is greatly reduced because
of this back-emf and if you avoid the moviment of the rotor, the
current should be so large that could damage the equipment.
http://www.newton.dep.anl.gov/askasci/phy00/phy00351.htm
Which prooves the point that BOTH dc armature and ac rotor motors have
back EMF!
Oscar_Lives
My sister is the Special Ed teacher-- sorry I do not have the experience
needed to communicate with the Mentally Retarded or the Emotionally
Disturbed.
s...@aaronj.com
> The back-emf argument is also bullshit. Back EMF is 'out-of-phase' and
> counteracts the inputted energy. It hurts you.. not helps.
Totally incorrect!
Back EMP reduces the voltage and hence the current.
Without back EMF (stalled motor), the lack of back EMF to "buck" that
applied votage will cause the current to be E/R which is much, much,
higher than when rotating.
How does back EMF hurt by reducing the CURRENT?
You have the EMF 'bucking' concept right but your thinking is out of
phase 180*.
Bubba
and argueing with you would be like fighting a sword fight and YOU
with no sword.
Honestly, Your ramblings are worse than stormy and Todd all rolled
together.
Climb back up the skylight and shut it on your way out.
Bubba
AKS
So you don't have to look for other female
that is nice to know
Bubba
Thats sweet. Too bad they didnt tell you that they send you out on 5
hr drives each day to get you out of everyone else's hair.
You drive a lot, I bet.
By the way..............I wouldnt be bragging about $135. In reality,
that aint shit. You have 5 hrs at $135 hr and a GOOD service tech
running the residential circuit can drag that in in an hour.
Bubba
AKS
I know my english is poor but you are dumb!!!!!! Whaooooo
Oscar_Lives
What the fuck are you trying to say here? I honestly cannot understand your
drunken spewage.
Oscar_Lives
Yeah, but Bubba is capable of learning. You are too figgin' brain dead to
learn the obvious.
Bubba
wrote:
I am not!.........damit!
Diddo sayz dat. :-)
Bubba
AKS
that don't have respect for self or others
have nice day Dido
Bob_Loblaw
AKS wrote:
> Thanks Bubba that is why I get paid to travel up to 5 hours
> in one direction and getting paid $135.00 per hour
That's because they're hoping you'll keep on going!
--
Respectfully, Bob
Bob_Loblaw
> I know my english is poor but you are dumb!!!!!! Whaooooo
Even when we understand what you're trying to say (albeit rarely), you
still don't make any sense!
You just don't have the knowledge it takes to be a good tech.
--
Respectfully, Bob
Bob_Loblaw
Bob_Loblaw
> Oscar get some experience and you bud! then talk
In other words...."HICCUP!!!"
--
Respectfully, Bob
Bob_Loblaw
> So you don't have to look for other female
> that is nice to know
WOW!!
Dildo, you are SOOO CLOSE to making sense!
--
Respectfully, Bob
Bob_Loblaw
> have nice day Dido
We'd all have a GREAT day if we read in the papers that you offed yourself!
--
Respectfully, Bob
