Bad capacitor in belt sander? Help needed

[Olinrj]

I have a delta 1" x 30" belt sander model 31-070, bought used. I cleaned out all the sawdust and ran it a few times but the motor didn't want to start on its own. I would move the belt to get it going and it would run, poorly. Recently I tried to use it but the motor wouldn't spin, just hum, even with a start assist. My troubleshooting led me to think that the capacitor is bad but don't have enough electrical troubleshooting experience to confirm this. Could someone point me in the right direction?

Thanks,
Bob

 

[exmaxima1]

I have a delta 1" x 30" belt sander model 31-070, bought used. I cleaned out all the sawdust and ran it a few times but the motor didn't want to start on its own. I would move the belt to get it going and it would run, poorly. Recently I tried to use it but the motor wouldn't spin, just hum, even with a start assist. My troubleshooting led me to think that the capacitor is bad but don't have enough electrical troubleshooting experience to confirm this. Could someone point me in the right direction?

Thanks,
Bob

You could be right about the capacitor. It's a run cap, 16uF 125vac (minimum), and if bad you will lose current in a set of the coils, and performance essentially like you described. Good luck finding it from Delta, as I believe it has been discontinued for several years now. See how much room you have and try a substitute that fits.

 

[Bigbandguy]

As long as the working voltage is similar or higher you can probably get away with a value that is a little higher (not lower) Keep it in the ballpark and you can likely find a substitute that will work.

 

[Olinrj]

Thanks for the quick info. The cap is 12 mfd 250 volt. Don't know if it is original or not. I haven't found any of the same spec online yet. What tolerance is acceptable for deviating from these values?

Thanks,
Bob

 

[exmaxima1]

Thanks for the quick info. The cap is 12 mfd 250 volt. Don't know if it is original or not. I haven't found any of the same spec online yet. What tolerance is acceptable for deviating from these values?

Thanks,
Bob

I've seen values of both 12uF and 16 uF for that Delta model capacitor. I would stay in that range. Run caps are different than start caps, and you don't want to pick an arbitrarily higher value as it could overheat the motor.

 

[Olinrj]

Thanks! I'll do some searching tonight and see what I can find

Thanks,
Bob

 

[pattenp]

Use same mfd/uf, higher voltage doesn't matter. 12mfd/uf 450v is okay. Finding physical size to fit will be the challenge.

I believe you need a CBB60 12uf.

 

[timtam4]

I am looking for the same capacitor for my belt sander. I have found several I could order but they either say start capacitor or run capacitor??? was curious if and where you may have found one??? My original capacitor is burnt completely through. Without this thread I would have been at a loss. Thanks to you all.

 

[rick58]

This came from a bench belt/disc sander. An older allied 120 volt. I cant make heads or tails of it. It was sizzling and leaking some awful smelling stuff from inside. The sander will still start and work bit not really good. This capacitor looked odd as it wasn't mounted and looked too large. It will start and run. After I connected the leads together. Any thoughts? This an old allied looks new but isn't.

 

[rick58]

Oh and its it a run or start.?

 

[Snip's]

I get mine from this company.... They have both run and start capacitors...
https://www.airstarsupply.com/products.aspx?cat=372

 

[wyliesdiesels]

8yr old thread

 

[dogdog]

This came from a bench belt/disc sander. An older allied 120 volt. I cant make heads or tails of it. It was sizzling and leaking some awful smelling stuff from inside. The sander will still start and work bit not really good. This capacitor looked odd as it wasn't mounted and looked too large. It will start and run. After I connected the leads together. Any thoughts? This an old allied looks new but isn't.

yea 8 yo thread... since its already revived..

It looks like the cap you have is a 3 in one 6uf x 3 electrolytic capacitor, not 100% sure about the since the pic is kinda dark..

this is my guess.... It looks like one Common on top and a jumper to the middle of the three connector points disabling one of the 3x 6uf capacitors and you have a jumper on the bottom left and bottom right point that would have make the 2 of the 6uf capacitors in parallel and would be 6+6=12uf. probably not a factory one but a replacement by previous owner ? I would try a 12uf. Plenty available on eBay if you search... if you still wanted to trouble shoot, it seems like only 1 of the two cap in parallel are bad and is shorting or burning up inside. you can take pic and unsolder everything and test for capacitance and what ever that other that is called on caps. and you have 3x cap there and if only one is bad, you can probably use the Un-used one.



if it is Me... I go get a new cap. those CBB 12uf ones would be fine, at worse you are out of $15.

with electrolytic caps this old, I would be worry about those liquid being PCB... don't sniff it too much might be very bad for your health.
your cap is dated 1974....
"The manufacture of PCBs was stopped in the U.S. in 1977"

 

[rick58]

Yea that's case is cracked on top and it smells lethal. It boiled out a bunch of liquid orange in color and it hardened after cooled. Does this make it a run capacitor or a start ?

 

[rick58]

I've found some that are 12 uf but they are 250 volt not 150 volt? Does it matter as long as the uf is 12? End the is the cap a run or start? Thanks for the lesson on these. I know that liquid had something bad in it. Suspected pcp but now having them confirmed scares me.

 

[dogdog]

I've found some that are 12 uf but they are 250 volt not 150 volt? Does it matter as long as the uf is 12? End the is the cap a run or start? Thanks for the lesson on these. I know that liquid had something bad in it. Suspected pcp but now having them confirmed scares me.

Higher voltage is fine as long as you can fit it in what ever casing.

Run cap/ start cap Dependent on how it is hook up to motor. Can’t tell from your cap marking. With lower capacitance like 12uf you can pretty much assume it’s a run cap type. Don’t think they are start cap this low capacitance.

Run cap/ start cap is just a term for motors they are capacitors. Run cap I think it’s just a normal capacitor non polarized that will take ac or dc. The start cap uses two dc caps and parallel in reverse to get higher capacitance and non polarized. But that makes it not good to hook up power for long terms.

Motor wise, the run cap is connect in series with the run coil of the ac motor and start cap is also connected in series but have a centrifugal switch to disconnect the cap from the coil after the motor spins up to speed dependent by the governor.