Starting Capacitors

What sort of motor?

What sort of supply?

<...help me dude...>

Please give the forum the information needed to obtain the required help.

a single phase motor i guess of the fridge and air conditioner. probably with 110 Volts supply.

OK. The capacitor is there to introduce a phase shift to the starter windings so that the motor begins to spin in the right direction. Once running, the circuit can be, and usually is, switched out-of-circuit, and the motor continues to run.

Provided the supply voltage does not exceed the capacitor's rated voltage, then the life of the capacitor will be indeterminably long. The converse is also true.

but should it be safe to touch both terminals of the capacitor, just for curiosity sake. I touch that one, may be today.

" I KNOW ELECTRICITY!!! "

It is really nice one

110V can give a life-threatening electric shock, though most people will survive it.

ok, so is capacitor only charge or energized during the motor is running or de-energize already? if you give me circuit diagram, i happy so much.

Circuit diagrams may be obtained by contacting the motor manufacturer directly.

The state of charge of the capacitor when the motor run circuit disconnects it from the start winding is indeterminate on an AC supply, and of no real concern.

Even if rotor is rotating, it do not induced electricity?-the start winding? may be i only touch that one, it's safe then.

Don't touch any of them, unless an electric shock is the desired outcome.

But, what if I backwards the termination of capacitor? no electricution effect to touch?-may be i only touch this one if no energy inside, or is it effect to motor?

Are you really intending to commit suicide. In this case you may be successful or may not also,so find a better method. As I understand this forum is to help people with their genuine technical doubts. As per electricity act in any country touching a live line is prohibited. It is not fun to play with electricity. Even discharge from charged condensers can kill a person. It is not the voltage level that matters. So my advice is simple, If you are not competent person do not work on electricity. If you want to do experiments do it under proper supervision. During investigation of a electrocution case it was found that a 36 volts leakage killed the person.

There are two types of windings used to start the directional rotation of motors. One is switch off the other is not. The capacitor is being used as a current limiting device as these windings the conductor they are made from is small.

You should not touch any electrical device especially a capacitor with out checking that it's discharged with the proper test equipment.

Electrical current passing through any device effects it's service life.

Go ahead. Voltage won't kill you. It's those AMPs you have to be careful of. So if your service is rated at less than1/2 AMP you can probably lick the cap without permanent damage.

Advice: Ways to Help a Burnt Tongue?!

I just about offered similar advice, something like:

"You (our OP) seem determined to touch something, so go ahead. In fact, give it a lick. I understand charged capacitors taste like chicken... "

But I thought better of it. Had I thought of offering Advice: Ways to Help a Burnt Tongue in the same post, I may have pressed forward.

I think I'll contact those guys... Ways to Help a Burnt Tongue may be a good addition to the Book Of The Month offering at LynDoor™ Press.

[edit] I just realized... this thread is authored by AP#1

There's no fool like a determined one.

I licked a 9 V battery once, and only once. It didn't taste like chicken to me.

holy crap, what is taste like? I am no fool, i just touch no tasting so far.

holy crap, what is taste like? I am no fool, i just touch no tasting so far.

Going by what you want to do (touch a live wire), i question your claim to non-foolishness. Whether you touch or taste electricity, you will feel like the second word, not qualified by the first.

Please don't make me tell you why I know you are right! -- JHF

Straight up answer, no smart aleck response: Yes, you will get shocked while the motor is running. Don't touch the terminals.

Yes, the service life is affected. Service life for start capacitors depends on the number of on/off cycles and the design engineering of the capacitor.

s'okay...The Dude abides...

Single-phase motor start capacitors are almost always aluminum electrolytic capacitors. If they are operated within their rated voltage, they seldom undergo catastrophic failure from puncture of the aluminum oxide dielectric, but high temperatures negatively affect their service life.

The electrolyte is a conductive solution that comprises one plate of the capacitor. As water in the electrolyte evaporates, the effective area of that plate decreases. When the effective area has been sufficiently reduced, the diminished capacitance is no longer able to pass enough out-of-phase current to the start winding to produce a rotating magnetic field strong enough to overcome the friction and inertia of the motor and its load, and it's time to buy a replacement.

"Digital Voltmeter": You touch your fingers to a live circuit; the number of millimeters they bounce is equal to the voltage. For example, if you touch a 2000-volt circuit, your hand will bounce 2000mm, which will tear your arm off. Don't try this at home, or without adult supervision.

Why don't you just put a meter on what you so fervently want to touch and see if there is power there?

I too, would post this question as an Anonymous Poster, because I sure as hell would not want anyone to know who the fool was. It seems like you know just enough to be a danger to yourself. Maybe, but hopefully not, we will see or hear about the Darwin Theory being demonstrated. Please ask your next of kin to post your results here on CR4

Redneck last words! "Hey Ya'll watch this!"

You left out the "Hold my beer." -- JHF

Now why don't any one tell this man that current does not pass through a capasitor [condenser].

Please, anonymous, get an old capasitor, open it up to find out what it looks like inside....and start reading up on electricity before U start experimenting dangerously!

Can some-one tell me how to determine what capacity cap must have for a single fase motor if one has no dope on the motor?