Capacitors

Ken D.

I would not reduce the voltage rating, even temporarily. The comp. would over load, how much, depends. The compressor is too expensive and the clean up after a burn out is something you would want to avoid. Leave it down until the proper parts are obtained.

Barrington White

Run Capacitors

Lets say you are working on a compressor that is rated to have a 60 microfarad 440 Volt capacitor and all you had was 70 microfarad 370 Volt capacitor so you decided to put it in. What would happen to the Compressor?

Lets say you had half the amount of refrigerant that was suppose to be in there, do you think the compressor could overcome that load and start with that same capacitor?

Lets say you had a fully charged system, do you think that compressor would over come that load and start, with that same capacitor?

Paul Fredricks_3

Wow

You've got a lot of questions Nate. The capacitor can exceed voltage (a 440v cap will work in place of a 370v cap). The MFD can vary by 10%, which basically means you need the right MFD cap. What will happen if it's wrong? I don't know. Don't find out. Use the right parts for the job. I'd guess the compressor would run less efficiently/draw more amps. Just a guess.

lee_7

like paul stated a 440 v will work in place of a 370 v, but a 370 v won't work in place of a 440 v

Techman

WOW also

Nate,as Dan H says "IT DEPENDS".There's alot of maybe's or could be's in your Q.The bottom line is DON"T DO IT!The comp may start and run BUT for how long AND at what damage to the comp.For 2 minutes? 2 hours? 2 days? Once damage is done it can't be undone!

Rich W

ELI the ICE man

> Lets say you are working on a compressor that is

> rated to have a 60 microfarad 440 Volt capacitor

> and all you had was 70 microfarad 370 Volt

> capacitor so you decided to put it in. What

> would happen to the Compressor?

>

> Lets say you

> had half the amount of refrigerant that was

> suppose to be in there, do you think the

> compressor could overcome that load and start

> with that same capacitor?

>

> Lets say you had a

> fully charged system, do you think that

> compressor would over come that load and start,

> with that same capacitor?

Rich W

ELI the ICE man

You're right on target about starting torque.

The motor coil is an inductor.

Voltage (E) leads current (I) in an inductive (L) circuit-that's ELI.

When voltage and current are out of phase like this, your torque drops.

Adding just the right capacitance brings the voltage and current back in phase for max starting torque...

FYI Current leads voltage in a capacitive (C) circuit. ICE

JackEnnisMartin

Running Caps.

Hello
I have been asked this question many times and I will say it again: USE A CAP. WITH A HIGHER RATING OR THE ORIGINAL VOLTAGE NEVER-- EVER USE A CAP. WITH A LOWER VOLTAGE RATING.I have seen the cap that is undersized in voltage instantly bulge causing winding damage and once - I hope it is only once the cap. blew a crack in the metal of the cap. Not a pretty or safe result. The cap. voltage is rated at the inrush voltage of the machine and is carefully engineerd for safe orperation. Good luck and remember -- WEAR SAFETY GLASSES WHENEVER YOU DO THIS KIND OF WORK -- you are gifted with one pair of eyes. Good luck
and all the best -- hug your kids we are the past they are the future.
Jack Ennis Martin

Techman

370 0r 440

Hi Nate,the next chance you get,go to a unit that you KNOW is running GOOD,and do a running voltage test.First ,turn off the unit by means of the disconnect and remove the comp terminal block cover.Then restart the unit. Then test for line voltage at the line side or load side of the contactor.Then check the voltage on the comp terminal block,First test C-R and you will get the same voltage that you had at the contactor.Then test the voltage on C-S and you will get a higher than line voltage reading.Some comp's will have 320vac or so,some will have 280vac or so thus the required 370vac run cap.Then some comp's will have 390vac or so ,some will have 415vac or so, thus the required 440vac run cap.So you cannot put a 370vac run cap on a comp that "produces" 415vac on the start winding.Every comp w/ a run cap is this way.Test away and see!

Eugene Silberstein 3

Very Important Terry

Sounds like you can now teach a lesson on how potential magnetic relays work!

Barrington White

> Hi Nate,the next chance you get,go to a unit that

> you KNOW is running GOOD,and do a running voltage

> test.First ,turn off the unit by means of the

> disconnect and remove the comp terminal block

> cover.Then restart the unit. Then test for line

> voltage at the line side or load side of the

> contactor.Then check the voltage on the comp

> terminal block,First test C-R and you will get

> the same voltage that you had at the

> contactor.Then test the voltage on C-S and you

> will get a higher than line voltage reading.Some

> comp's will have 320vac or so,some will have

> 280vac or so thus the required 370vac run

> cap.Then some comp's will have 390vac or so ,some

> will have 415vac or so, thus the required 440vac

> run cap.So you cannot put a 370vac run cap on a

> comp that "produces" 415vac on the start

> winding.Every comp w/ a run cap is this way.Test

> away and see!



I've tried that and I end up burning the tips on my volt meter leads

Techman

Darn!

What kind of meter do you have ? I hope you didn't touch probe tip to probe tip[L1 to L2], which would be a direct short !I test C-S all the time and NO problems!If it is physically hard to test at the comp terminal block ,then test at the run cap,from the wire that goes from the cap to the start winding and the other leg of line.And have the meter set on the 600vac setting,since you are testing for up to 440v. DARN!