Safely discharging a capacitor
paulfoel
micro-Farad one.
I think its dead anyway but I'm assuming I can check with a multimeter?
What sort of voltage/current is one of these likely to have?
Assuming it is still ' live' how do I discharge it to make it safe?
The3rd Earl Of Derby
Does your meter support capacitance? if not you're wasting you're time,
these are only a few pence anyway in a maplins outlet.
--
Sir Benjamin Middlethwaite
Andrew Gabriel
Most likely it is discharged through the motor windings unless
the switching is such that it gets disconnected, although
relying on the motor windings being intact is not smart when
the thing is known not to be working properly. Secondly, it
probably has a bleed resistor built in, although those can
fail too. I would probably just short it out with a screwdriver,
although that can in theory damage the capacitor. Leave it for
at least 5 minutes since last powered up, and then short out,
and you'll be fine. Making up a proper resistive discharger for
this one occasion just isn't worth it.
--
Andrew Gabriel
vortex2
> fail too. I would probably just short it out with a screwdriver,
> although that can in theory damage the capacitor. Leave it for
> at least 5 minutes since last powered up, and then short out,
> and you'll be fine. Making up a proper resistive discharger for
> this one occasion just isn't worth it.
>
> --
> Andrew Gabriel
I was in the local Maplin shop the other day and saw that you can purchase 1
farad (huge) capacitors for power supply smoothing chav's in car audio
systems.
Must be interesting when you accidently short one of these!
http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
David
Dave D
"paulfoel" <BertieB...@gmail.com> wrote in message
news:1135167798.3...@g43g2000cwa.googlegroups.com...
Does the motor have brushes and a commutator? If so, change the brushes
before you start looking elsewhere, they're seldom expensive and are a
consumable item. Capacitors may or may not last the life of an appliance but
brushes are certain to wear from day one and are usually the first suspect
in a misfiring/intermittant motor.
With brush type motors, the brushes wear down and consequently less pressure
is applied by the spring, causing a higher resistance/poorer connection
between brush and commutator. An arc is caused, which heats the brush and
can deform the casing causing the brush to stick, making the problem
increase exponentially. It also causes the commutator to become blackened
which makes matters even worse.
I'd take out the brush carriers and check the brushes move freely and that
there's plenty of length left on them. Also check the commutator is clean.
If the motor does not have a brush/commutator arrangement, I'd check all
connections are secure and check the control board for dry/cracked solder
joints before suspecting component failure.
Dave
Slurp
"vortex2" <dhe...@DELETE.firstsightvision.co.uk> wrote in message
news:yOqdnSvMGLmyyTTe...@pins.co.uk...
>
> Must be interesting when you accidently short one of these!
>
Nah - that's nancy stuff for kids
.... real man stuff here!
http://www.amasci.com/amateur/capexpt.html
Andy Dingley
wrote:
>Assuming it is still ' live' how do I discharge it to make it safe?
Stick a big screwdriver across it. This is bad advice for capacitors in
general, but for these motor capacitors used on 240V AC only it's OK.
There is minimal likelihood of there being any charge left in there,
you're only shorting it to make _sure_ before you touch it by hand. If
it _had_ been charged up by the Workshop Pixies beforehand, then it just
costs you a screwdriver and a pair of trousers.
If you're fooling with HT DC on capacitors, then fit proper bleed
resistors before you start and make yourself a discharging stick with a
resistor in it.
powerstation
"Dave D" <dave_d@dave_d.com> wrote in message
news:0KCdnSyIMLL...@pipex.net...
airsm...@hotmail.com
Dave D
"powerstation" <po...@station96.com.tw> wrote in message
news:dobp99$538$1...@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...
>
>>
>> Dave
> nonsense it is clearly an induction motor.
>
Probably, but I'm not at the OP's house to take a look and be certain this
is the case, and as the symptoms are classic signs of worn brushes, I
thought I'd mention it in case.
The rest of my advice about looking for bad connections before replacing
components is perfectly valid as well.
Dave
Sam Goldwasser
A capacitor with a digital readout? Now they've gone over the top! :)
--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.
paulfoel
powerstation wrote:
Yep. It is.
powerstation
by the capacitor being affixed too close to the motor, the spare part now
includes a bracket to move it further away. Sometimes even when the part is
replaced the motor subsequently burns out if the windings have been damaged
by a stalled motor.
Andy Dingley
>Probably, but I'm not at the OP's house to take a look and be certain this
>is the case, and as the symptoms are classic signs of worn brushes, I
>thought I'd mention it in case.
How many tumble driers use brushed motors?
How many brushed motors also have a capacitor?
Now this assumes that it _is_ a capacitor of course. If it does have a
brushed motor, I wouldn't be surprised if it had a line filter instead
and these can look very similar to capacitors.
CJT
Does anybody worry about the inrush current to these, and what that does
to one's alternator?
--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.
Palindr☻me
> vortex2 wrote:
>
>>> fail too. I would probably just short it out with a screwdriver,
>>> although that can in theory damage the capacitor. Leave it for
>>> at least 5 minutes since last powered up, and then short out,
>>> and you'll be fine. Making up a proper resistive discharger for
>>> this one occasion just isn't worth it.
>>>
>>> --
>>> Andrew Gabriel
>>
>>
>>
>> I was in the local Maplin shop the other day and saw that you can
>> purchase 1 farad (huge) capacitors for power supply smoothing chav's
>> in car audio systems.
>>
>> Must be interesting when you accidently short one of these!
>>
>> http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
>>
>>
>> David
>>
>>
>>
>>
> Does anybody worry about the inrush current to these, and what that does
> to one's alternator?
>
Car wiring is radial from the battery to alternator and from the battery
to load. The impedance of the battery is much lower than that of the
alternator radial circuit - thus transient currents will be met almost
entirely by the battery.
You may like to think what effect the starter motor has on the alternator.
Also, the energy stored in a capacitor depends on the capacitance and on
the square of the voltage. Rather than have a 1F capacitor on the 12v
line, it would be much better to go to the higher voltage power rails of
the amplifier and stick beefy capacitors there.
--
Sue
James Sweet
>
> nonsense it is clearly an induction motor.
>
>
Why do you say that? Most European washing machines use series wound
universal motors with carbon brushes. I've got a Creda washer sitting in
my basement right now awaiting arrival of a set of brushes amoung other
things, no idea how it ended up on this side of the pond but it's a cool
little machine.
James Sweet
>>http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
>
>
> A capacitor with a digital readout? Now they've gone over the top! :)
>
They went over the top years ago, those capacitors have been available
for a while.
Just try to find a car CD player anymore that looks at home in anything
but a gaudy racer boy Japenese compact. Seems like they're all fugly and
bubbly, loaded with useless distracting blinky lights and buttons so
small and jumbled it's impossible to operate them safely while driving.
James Sweet
> CJT wrote:
>
>> vortex2 wrote:
>>
>>>> fail too. I would probably just short it out with a screwdriver,
>>>> although that can in theory damage the capacitor. Leave it for
>>>> at least 5 minutes since last powered up, and then short out,
>>>> and you'll be fine. Making up a proper resistive discharger for
>>>> this one occasion just isn't worth it.
>>>>
>>>> --
>>>> Andrew Gabriel
>>>
>>>
>>>
>>>
>>> I was in the local Maplin shop the other day and saw that you can
>>> purchase 1 farad (huge) capacitors for power supply smoothing chav's
>>> in car audio systems.
>>>
>>> Must be interesting when you accidently short one of these!
>>>
>>> http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
>>>
>>>
>>> David
>>>
>>>
>>>
>>>
>> Does anybody worry about the inrush current to these, and what that does
>> to one's alternator?
>>
> No.
>
> Car wiring is radial from the battery to alternator and from the battery
> to load. The impedance of the battery is much lower than that of the
> alternator radial circuit - thus transient currents will be met almost
> entirely by the battery.
>
> You may like to think what effect the starter motor has on the alternator.
>
>
While this is true, don't forget that the starter motor will never be
operating under load while the alternator is producing any current
unless you're jump starting another car.
Bob Eager
wrote:
> > nonsense it is clearly an induction motor.
>
> Why do you say that? Most European washing machines use series wound
> universal motors with carbon brushes.
But we were talking about a dryer. They seem to use induction motors
(well, mine does).
--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk
powerstation
"James Sweet" <james...@hotmail.com> wrote in message
news:dsiqf.694$2B5.463@trnddc01...
But its NOT a washing machine he's fixing ! its a tumble drier
powerstation
>
>> > nonsense it is clearly an induction motor.
>>
>> Why do you say that? Most European washing machines use series wound
>> universal motors with carbon brushes.
>
> But we were talking about a dryer. They seem to use induction motors
> (well, mine does).
>
All the ones I have ever seen are, because they revolve the drum slowly, a
washing machine needs to spin at high speed
Andrew Gabriel
James Sweet <james...@hotmail.com> writes:
> Why do you say that? Most European washing machines use series wound
> universal motors with carbon brushes. I've got a Creda washer sitting in
> my basement right now awaiting arrival of a set of brushes amoung other
> things, no idea how it ended up on this side of the pond but it's a cool
> little machine.
A European washing machine operates its motor at a large
number of different speeds (and even gradually vary the
speed in some cases) throughout various stages of the
wash cycle, and depending on the wash program selected.
This is most easily done with a universal motor combined
with an electronic speed control board and servo feedback.
(It used to be done with an induction motor and solenoid
operated gearbox 40 years ago, but that's more expensive
and a lot less flexible.)
Tumble driers only have to be able to reverse the drum,
but don't need to change the speed. For this simpler
requirement, an induction motor tends to win.
--
Andrew Gabriel
James Sweet
> On Wed, 21 Dec 2005 19:56:57 UTC, James Sweet <james...@hotmail.com>
> wrote:
>
>
>>>nonsense it is clearly an induction motor.
>>
>>
>>Why do you say that? Most European washing machines use series wound
>>universal motors with carbon brushes.
>
>
> But we were talking about a dryer. They seem to use induction motors
> (well, mine does).
>
Yeah somehow I missed that we were discussing a dryer. The matching
Creda dryer does in fact have an induction motor in it, weird to see a
clothes dryer that will plug into a 15A 240v receptacle, US dryers are
almost universally 4KW.
The Natural Philosopher
Thats because youy get a really good one bult nto any car that chavs don't
buy.
The Natural Philosopher
> vortex2 wrote:
>
>>>fail too. I would probably just short it out with a screwdriver,
>>>although that can in theory damage the capacitor. Leave it for
>>>at least 5 minutes since last powered up, and then short out,
>>>and you'll be fine. Making up a proper resistive discharger for
>>>this one occasion just isn't worth it.
>>>
>>>--
>>>Andrew Gabriel
>>
>> I was in the local Maplin shop the other day and saw that you can purchase 1
>> farad (huge) capacitors for power supply smoothing chav's in car audio
>> systems.
>>
>> Must be interesting when you accidently short one of these!
>>
>> http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
>>
>> David
>>
>>
>>
> Does anybody worry about the inrush current to these, and what that does
> to one's alternator?
its nowhere as bad as what a statrter motor does...alternators are limited
anyway.
James Sweet
> Tumble driers only have to be able to reverse the drum,
> but don't need to change the speed. For this simpler
> requirement, an induction motor tends to win.
>
Why do they have to be able to reverse the drum? I've never seen a dryer
that did that, obviously they must exist but I'm not sure of the benefits.
James Sweet
>
> Thats because youy get a really good one bult nto any car that chavs don't
> buy.
Would be nice, but I'm afraid back in '84, '87 and '88 respectively,
cars didn't come with CD players of any sort, hence my need to install
aftermarket units in mine.
Not to mention I'm still not aware of any OEM units that will play MP3
discs, an essential feature to me that made all earlier CD players
virtually obsolete. 10 hours of music on one disc, no more fumbling with
CD's in traffic.
Bob Eager
wrote:
> Why do they have to be able to reverse the drum? I've never seen a dryer
> that did that, obviously they must exist but I'm not sure of the benefits.
Loads of them do it[1]...helps to untangle the clothes.
[1] except in the backwards USA?
raden
paulfoel <BertieB...@gmail.com> writes
>Going to attempt to change the capacitor on my tumble dryer... Its a 8
>micro-Farad one.
>
>I think its dead anyway but I'm assuming I can check with a multimeter?
>What sort of voltage/current is one of these likely to have?
>
>Assuming it is still ' live' how do I discharge it to make it safe?
>
stick a screwdriver across it - that'll discharge it
--
geoff
raden
airsm...@hotmail.com writes
STOP IT STOP IT STOP IT
You're giving me ideas
--
geoff
news07
<sl...@slop.slap> writes
>Nah - that's nancy stuff for kids
>
>.... real man stuff here!
>
>http://www.amasci.com/amateur/capexpt.html
>
>
Where does one start, any site that had the following in the disclaimer
'DISCLAIMER: the experiments described below are fantastically
dangerous, and they are described without reference to the
many precautions needed to guarantee the experimenter's safety.
Accidentally discharging these capacitor banks through your
body can not only kill, but can explode flesh and bone.'
Followed by
'PARENTS: I supply no detailed plans for reproducing these
experiments. Also, these experiments require large and
expensive lab equipment which is not obtainable by children.
(And the plans for an atomic bomb are safe for children too,
because kids can't afford to buy kilograms of Plutonium!)
If your kids have access to 5,000 volt high-current power supplies,
then they are already in great danger, whether or not they read
about my capacitor discharge experiments below.'
Has my respect!
--
Andrew Sinclair http://www.smellycat.org
use...@isbd.co.uk
> >
> > If the motor does not have a brush/commutator arrangement, I'd check all
> > connections are secure and check the control board for dry/cracked solder
> > joints before suspecting component failure.
> >
> > Dave
> nonsense it is clearly an induction motor.
>
electrical machines (including transoformers) are really induction
motors.
--
Chris Green
powerstation
<use...@isbd.co.uk> wrote in message news:40u3qrF...@individual.net...
current by means of various arrangements of inductance and capacitance that
alter the characteristics of the single-phase voltage and make it resemble a
two-phase voltage. Such motors are called split-phase motors or condenser
motors (or capacitor motors), depending on the arrangement used.
Single-phase squirrel-cage motors do not have a large starting torque, and
for applications where such torque is required, repulsion-induction motors
are used. A repulsion-induction motor may be of the split-phase or condenser
type, but has a manual or automatic switch that allows current to flow
between brushes on the commutator when the motor is starting, and
short-circuits all commutator segments after the motor reaches a critical
speed. Repulsion-induction motors are so named because their starting torque
depends on the repulsion between the rotor and the stator, and their torque
while running depends on induction. Series-wound motors with commutators,
which will operate on direct or alternating current, are called universal
motors. They are usually made only in small sizes and are commonly used in
household appliances.
david lang
> How many tumble driers use brushed motors?
I don't know, never had one apart, but I assumed they all did. Every
washing machine I've ever repaired had a brush motor, why would they use
induction on a tumble fryer as a matter of interest?
Dave
paulfoel
Andy Dingley wrote:
Nope. Definitely an 8 micro-Farad capacitor.
paulfoel
> by the capacitor being affixed too close to the motor, the spare part now
> includes a bracket to move it further away. Sometimes even when the part is
> replaced the motor subsequently burns out if the windings have been damaged
> by a stalled motor.
TB ? (Technical Brief?)
Where can I see this info?
powerstation
"paulfoel" <BertieB...@gmail.com> wrote in message
news:1135250203....@g49g2000cwa.googlegroups.com...
Sent to your email if it genuine
Peter
Andy Dingley
<davi...@nospamblueyonder.co.uk> wrote:
>I don't know, never had one apart, but I assumed they all did. Every
>washing machine I've ever repaired had a brush motor, why would they use
>induction on a tumble fryer as a matter of interest?
You use induction motors whenever you can - they're quieter (this is a
domestic appliance after all) and they're cheaper. The advantage of the
brushed motor is that they have much higher torque at low speeds or when
stalled (why they appear on power tools) and they're also more easily
controllable for variable speeds etc. There's a lot of things a washing
machine does that a tumble drier just doesn't need.
Tony Williams
david lang <davi...@nospamblueyonder.co.uk> wrote:
Relatively constant speed operation under variable load,
without the expense of speed-sensor and controller?
--
Tony Williams.
david lang
> You use induction motors whenever you can - they're quieter (this is a
> domestic appliance after all) and they're cheaper.
Odd. The only experience I have is with high pressure cleaners. The el
cheapo DIY jobbys have brush motors which make a terrible screaming noise -
but they use them to reduce costs.
>The advantage of
> the brushed motor is that they have much higher torque at low speeds
> or when stalled (why they appear on power tools) and they're also
> more easily controllable for variable speeds etc. There's a lot of
> things a washing machine does that a tumble drier just doesn't need.
I can see the logic in that, but I've always assumed (from my HPC
experiences) that induction motors were much more expensive.
Dave
Andrew Gabriel
"david lang" <davi...@nospamblueyonder.co.uk> writes:
> Andy Dingley wrote:
>
>> You use induction motors whenever you can - they're quieter (this is a
>> domestic appliance after all) and they're cheaper.
>
> Odd. The only experience I have is with high pressure cleaners. The el
> cheapo DIY jobbys have brush motors which make a terrible screaming noise -
> but they use them to reduce costs.
My 4-5 year old el-cheapo "Deltajet" (cheapest I could find
at the time, for hosing mud off the bicycles) is a 1200W
induction motor.
In the case of lawnmowers, I suspect the use of universal
motors is to make mowers into consumables, which people
will thus tend to change every few years. Just about every
characteristic of a universal motor is inappropriate for
a lawn mower. You can find mowers with induction motors,
but they tend to be in the better quality less well known
makes, which you have to buy from specialists rather than
DIY sheds.
>>The advantage of
>> the brushed motor is that they have much higher torque at low speeds
>> or when stalled (why they appear on power tools) and they're also
>> more easily controllable for variable speeds etc. There's a lot of
>> things a washing machine does that a tumble drier just doesn't need.
You can also get a more powerful universal motor in a smaller
physical size, but generally they are significantly less efficient.
E.g. you need around 30-50% more powerful universal motor to get
same cutting power out of a lawn mower as you do from an induction
motor, and the universal motor will run too hot to touch even
with forced air cooling, whilst the induction motor only runs
luke warm. I don't know if this is an inherent design issue, or
if it just reflects that the induction motors are found in better
specified/designed products. Also, universal motors generally run
much faster, indeed much too fast for many applications where they
need to be geared down (e.g. mowers, drills, etc).
> I can see the logic in that, but I've always assumed (from my HPC
> experiences) that induction motors were much more expensive.
I don't see why they should be technically. It may be a question
of supply and demand, what the market will bear, etc.
--
Andrew Gabriel
soup
> Why do they have to be able to reverse the drum? I've never seen a
> dryer that did that, obviously they must exist but I'm not sure of
> the benefits.
To stop the clothes getting tangled, also the stopping then going the
other way will help stop areas of stagnation (and hence slow drying)
occuring. Mine a "Tricity Bendix TM 220 W" certainly has this drum
reversing indeed it is sold as a feature of this model and is called
"reverse action".
--
This post contains no hidden meanings, no implications and certainly no
hidden agendas so it should be taken at face value. The wrong words
may be used this is due to my limitations with the English language .
Andrew Gabriel
I've got this terrible urge to dig out some perspex
sheet I've got left over in the garage...
I built a Van de graff generator when I was at school,
but that was rather disappointing. (On later reflection,
I'm not sure the belt material I used was a good enough
insulator.)
Then I built a high voltage generator using a car ignition
coil, EHT valve rectifier, and a capacitor made from
kitchen foil and a large roll of cellulose acetate
overhead projector film. I got really 'cracking' 4"-5"
sparks from it for a day, until the cellulose acetate
broke down.
--
Andrew Gabriel
Andy Dingley
<davi...@nospamblueyonder.co.uk> wrote:
>> You use induction motors whenever you can - they're quieter (this is a
>> domestic appliance after all) and they're cheaper.
>
>Odd. The only experience I have is with high pressure cleaners. The el
>cheapo DIY jobbys have brush motors which make a terrible screaming noise -
>but they use them to reduce costs.
Induction is cheaper for a specific power, or for almost all large
motors. Brushed is cheaper for small low powered motors that still need
high torque. If you can go to a direct-drive design, then using a
brushed motor and no gearbox is usually cheaper, but you need a motor
that can provide the required torque on its own shaft.
James Sweet
> In the case of lawnmowers, I suspect the use of universal
> motors is to make mowers into consumables, which people
> will thus tend to change every few years. Just about every
> characteristic of a universal motor is inappropriate for
> a lawn mower. You can find mowers with induction motors,
> but they tend to be in the better quality less well known
> makes, which you have to buy from specialists rather than
> DIY sheds.
>
>
I suspect the main reason there is power to weight/cost ratio. You can
get a tremendous amount of power out of a compact universal motor but an
induction motor suitable for that would be a lot heavier and more
expensive. A universal will burn up at the drop of a hat though, a
friend of mine retrofitted his electric mower with a surplus pool pump
motor when that happened, he said it worked really well but those motors
are expensive new.
James Sweet
> James Sweet wrote:
>
>>Why do they have to be able to reverse the drum? I've never seen a
>>dryer that did that, obviously they must exist but I'm not sure of
>>the benefits.
>
>
> To stop the clothes getting tangled, also the stopping then going the
> other way will help stop areas of stagnation (and hence slow drying)
> occuring. Mine a "Tricity Bendix TM 220 W" certainly has this drum
> reversing indeed it is sold as a feature of this model and is called
> "reverse action".
Well damn, I cleaned up and tested out the Creda dryer which is the mate
for the washer I've been refurbishing and it does in fact reverse the
drum periodically. Nifty little machine, not like anything I've used
before. If the washer was a bit larger capacity and I didn't have a big
Neptune front loader already I'd definitely keep this pair but a friend
of mine has more of a need for them than I do.
david lang
> In the case of lawnmowers, I suspect the use of universal
> motors is to make mowers into consumables, which people
> will thus tend to change every few years.
Ditto cheap high pressure cleaners. The Ł30 B&Q jobbies have a motor life
of 10-12 hours. Even a cheap Chinese induction motor will run for 50-60
hours. Qua;ity industrial machine will have an induction motor rated at
800-1000 hours.
> Just about every
> characteristic of a universal motor is inappropriate for
> a lawn mower. You can find mowers with induction motors,
> but they tend to be in the better quality less well known
> makes, which you have to buy from specialists rather than
> DIY sheds.
Ditto cheap high pressure cleaners.
> Also, universal motors generally run
> much faster, indeed much too fast for many applications where they
> need to be geared down (e.g. mowers, drills, etc).
Indeed. High pressure pump wants to run at 1400 rpm, or 2800 at a pinch.
The cheapo HPCs use a ring gear to slow the motor down.
>> I can see the logic in that, but I've always assumed (from my HPC
>> experiences) that induction motors were much more expensive.
>
> I don't see why they should be technically. It may be a question
> of supply and demand, what the market will bear, etc.
Maybe mass production. Many el cheapo HPC's use domestic vacuum cleaner
motors.
Dave
James Sweet
>
> Ditto cheap high pressure cleaners. The Ł30 B&Q jobbies have a motor life
> of 10-12 hours. Even a cheap Chinese induction motor will run for 50-60
> hours. Qua;ity industrial machine will have an induction motor rated at
> 800-1000 hours.
>
>
1000 hours sounds awfully low for a good induction motor. The 3HP main
pump in my spa runs 4 hours a day for the filtration cycles and it's 10
years old. Isn't used year round but it must have at least 5000 hours on
it and the bearings felt like new when I replaced the shaft seal. Theres
well used equipment at a friend's machine shop with motors dating back
to the 1940s that are still running strong.
david lang
> 1000 hours sounds awfully low for a good induction motor.
Depends on what you pay for them. On a cold water HPC the motor will be
about 65% of the total build cost, so they don't use the top grade -
besides, the pump etc won't last much more than 1,000 hours anyway.
Dave
Ascro
Sam Goldwasser wrote:
> > http://search.ebay.co.uk/search/1-farad-capacitor_W0QQfclZ4QQfnuZ1
>
> A capacitor with a digital readout? Now they've gone over the top! :)
>
I think that you need to understand the market they are trying to sell
into. When you see the claim "A CAPACITOR stores current." you see what
level they are aiming at!