Author Topic: 45mfd cap  (Read 611 times)

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Offline thedoc298Topic starter

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45mfd cap
« on: June 23, 2019, 04:03:31 pm »


Is their any difference between a 45uf 250 volt run cap and a 45uf 250 volt start cap. I know that they are used for different purpose, but I think their should be no difference. Any ideas
 

Offline Ian.M

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Re: 45mfd cap
« Reply #1 on: June 23, 2019, 04:07:25 pm »
A start cap has much higher losses.  If you try to use one as a run cap, it *will* go BANG!
 

Offline thedoc298Topic starter

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Re: 45mfd cap
« Reply #2 on: June 23, 2019, 04:12:35 pm »
how would that be determend on a cap tester
 

Offline ArthurDent

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Re: 45mfd cap
« Reply #3 on: June 23, 2019, 04:14:10 pm »
A motor start cap is a non-polarized capacitor (or 2 caps back-to-back) and designed for very short use time per start. I wouldn't use one for a DC power supply filter or visa versa. Very bad!
 

Offline schmitt trigger

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Re: 45mfd cap
« Reply #4 on: June 23, 2019, 04:23:13 pm »
Start capacitors are almost always clearly labeled as such, because of the risk of running it continuously.

Its ESR is about 10 times that of a run capacitor of the same capacity and voltage.
 

Offline thedoc298Topic starter

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Re: 45mfd cap
« Reply #5 on: June 23, 2019, 04:29:48 pm »
Thanks, that is something that will show up. The original start did have very high esr. Thanks
 


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