Motor Caps.

[Ken9876]

How would one figure out what size cap. a motor or compressor needs if the proper one is missing and no info on correct cap. size?

 

[Rockyd]

Any manufacturer name, frame size, or info available???

 

[Ken9876]

I don't have a motor that I'm trying to find the cap on now, someone asked me the other day and I didn't have an answer so I'm in search of one. I just want to know if there is a way of figuring it out.

 

[Rockyd]

Boater Bill in the forum may know the formula. A reputable capacitor outfit like Sprague, would be happy to run the numbers for you, or give you a chart, because they have a financial interest in the solution. Ugly's Electrical references has a section too.

Don't feel like scratching around with ELI the ICE man, to get the corrective KVAR values per tangent formulas. Besides, it's Saturday, and it might make my head hurt to think that hard, aand try to type it, to where it comes out easy.

 

[mdshunk]

When I did HVAC work, I bumped into this with great regularity. I just dialed in various cap values with a decade box until I got one that started the compressor with a reasonable starting amp draw.

 

[Rockyd]

Thanks Marc. In an effort to kill ignorance, clue me into what a decade box is?

 

[mdshunk]

Thanks Marc. In an effort to kill ignorance, clue me into what a decade box is?

Feel free to Google it.

A decade box is a test tool that will allow you to dial in capacitance, resistance, or inductance (depending on the type of decade box).