Thread: Possible failed capacitor?

Originally Posted by mic-d

Is this something that I could swap out?

Yes, it’s very easy. I’ve done it on a few motors.

turn the power off first, preferably unplug from power

Originally Posted by mic-d

Googling suggests a failed run capacitor.

It will probably be a failing start capacitor. Your motor may have both. They are different so make sure that you get the right type.

Originally Posted by Bohdan

It will probably be a failing start capacitor.

Well spotted. I missed that.

I opened the capacitor compartment and discovered both the run and start capacitors are toast. The start capacitor is on the right, I found reference that this is a non polarized capacitor so can hook the replacement up either way. Does anyone know about the run capacitor? I can't see any labels on the capacitor, which suggests it doesn't matter either, and the wires are all blue. I can label the wires when I cut out the run capacitor, but bit hard to know with what if they're not labelled on the capacitor! The next problem will be the spec of the run capacitor, it has burst right through the label

IMG_9931.jpg

The motor is 240v Alternating Current !
There is no positive or negative as it alternates between the two.

Originally Posted by mic-d

Does anyone know about the run capacitor?

Both caps need to be NP.

Originally Posted by mic-d

The next problem will be the spec of the run capacitor, it has burst right through the label

Powermatic is a well-known brand. Should be easy enough to find out what value it is.

What size (?kw) is the motor?

I dunno, but it says 3hp

For a 3 HP motor a run capacitor of between 60uf and 80uf, 440V should work. I calculated 74.2uf

Not sure how difficult your capacitor is to find, I was able to get one for my Hammer bandsaw from an air conditioning place.

Originally Posted by AlexS

Not sure how difficult your capacitor is to find, I was able to get one for my Hammer bandsaw from an air conditioning place.

Not so easy to find the big start cap. Tried two electrical wholesalers and a dedicated motor refurb company with no luck. The company I bought it from are looking into it for me, but I also have one more business to try who have a capacitor of that rating listed, I just have to check Monday if they have it in stock.

Originally Posted by mic-d

Not so easy to find the big start cap. Tried two electrical wholesalers and a dedicated motor refurb company with no luck. The company I bought it from are looking into it for me, but I also have one more business to try who have a capacitor of that rating listed, I just have to check Monday if they have it in stock.

Not sure where in Brisbane your located but have you tried a Jaycar store ?

Originally Posted by droog

Not sure where in Brisbane your located but have you tried a Jaycar store ?

yep. This is a big cap 400 uF 125v

but two of the leads I have left will have it