bench grinder capacitor help

[taumac]

My beloved dayton bench grinder started to smoke tonight. I took it apart and saw smoking from capacitor. So I want to fix so went online and started looking but got confused when they asked about micro farad. Heres a picture and can someone point me in right direction and do places locally carry these or is it something I have to buy online.... thanks

 

[ForceFed70]

That looks like a 100 Microfarad 125V Max cap.

Usually Micro is listed an "uF" but my guess is because it's old they used MFD.

Cap smoking may be an indicator of a different problem, but should be cheap enough to replace anyway.

 

[pattenp]

That type of capacitor is rated in MFD. This is what you need .....
http://www.mscdirect.com/product/08687519

 

[taumac]

Ok radio shack doesnt carry it at least in store. I know guy that gave it to me said it had bad swicth or dirt/ **** in switch. Every once in a while just move switch and it will stop or if doesnt start jiggle switch and works fine. Last night when posted this heard a pop and then saw smoke. I then took apart turned it on ran fine with just very small smoke from time to time but it was from cap. I gonna just order new cap and go from there. Hopefully thats all it is. Thanks guys

 

[Rhyno]

When a capacitor goes bad, it typically will "swell" a bit. You can look at it and one of the end caps will be "domed" versus flat. An analogy might be a flat, $.25 quarter versus a quarter that has been shot with a .38 special.

Sometimes, the sides (of the capacitor) will not be parallel, when bad. If the case of the capacitor isn't swollen, you can measure it with a Volt/Ohm meter, to determine if it's bad. (if the V/O meter has the "Cap" feature)

It sounds like you need to focus on the switch. Either way, capacitors are easily found at an Electronics store (not BustBuy, either), an A/C repair shop, etc...

Good luck....

 

[Norcal]

Try a motor repair shop, or use a search engine, just enter the cap specs.

http://www.bing.com/search?q=100+MF...&pq=100+mfd+125vac+capacitor&sc=0-9&sp=-1&sk=

I had better luck w/ www.startpage.com entering 100 MFD 125VAC Capacitor, it will not let me post a link w/ results like Bing. I do not use Google.

 

[Greatbear]

There is a relay next to the capacitor used for starting. Current from the run winding passes through the coils you see wrapped around the relay, switching the capacitor and start winding into the circuit. Once the motor reaches running speed, the current flow drops dramatically in the run winding, the relay disconnects the start winding and capacitor from the circuit. Many of these relays are position sensitive, trying to run the grinder inverted will sometimes prevent the relay from disconnecting. This can burn out the cap and/or the start windings in the motor. Test the grinder in the normal position.

 

[cnc-me]

Grainger carries capacitors

 

[taumac]

There is a relay next to the capacitor used for starting. Current from the run winding passes through the coils you see wrapped around the relay, switching the capacitor and start winding into the circuit. Once the motor reaches running speed, the current flow drops dramatically in the run winding, the relay disconnects the start winding and capacitor from the circuit. Many of these relays are position sensitive, trying to run the grinder inverted will sometimes prevent the relay from disconnecting. This can burn out the cap and/or the start windings in the motor. Test the grinder in the normal position.

Big thanks..... Cause it worked fine until I put it in wall it that position.when I get home later ill try on flat. I remember testing it upside down..... And it worked fine.

 

[taumac]

Just a update.... I put the grinder back flat and used it some it few past weeks with no smoking or isuues at all. I guessing cause of that relay it had to be flat.... thanks guys

 

[wyliesdiesels]

Even though its working again, I would still test the cap, switch and also now the relay too, to make sure everything is still A OK! Look around for 'smoked'/blackened parts/areas which can indicate what was smoking! Better to be safe than sorry!

 

[taumac]

Even though its working again, I would still test the cap, switch and also now the relay too, to make sure everything is still A OK! Look around for 'smoked'/blackened parts/areas which can indicate what was smoking! Better to be safe than sorry!

Your right I should, I know swicth was the main issue. I had one around here i know of.... just got ta find it and swicth it out then check rest out.

 

[ALTEREGO]

Hi Taumac,

Were you able to resolve your issue permanently? I'm trying to repair my Dayton 4Z123F bench grinder, but I'm not sure what is the issue, the relay, the wiring or the capacitor.

I installed a new capacitor but it burned. I installed the old capacitor and it didn't smoke/burn but it just doesn't work (have to give the wheel a little push to get it started otherwise it just hums). I'm not sure if I installed the relay backwards when I put it back in, I know that would create an issue.

I looked at the schematics from the manual and I think the wiring is ok (as long as the relay was reinstalled in the correct position as mentioned above).

The capacitor should be a starting motor capacitor 100 mfd 125v, correct? My grinder had a cheap Chinese replacement so I'm not sure if that's the correct capacitor.

See my thread below for pictures and additional info.


Any advice will be greatly appreciated, thank you.


https://www.garagejournal.com/forum/showthread.php?t=475778

 

[Dagny]

A refrigeration man can probably fix you up with a solid state relay that will work.

 

[ALTEREGO]

A refrigeration man can probably fix you up with a solid state relay that will work.

Thank you Dagny, a HVAC or a guy that fixes fridges? I hope the former, I have a friend that owns a HVAC business, don’t know any guys that fix refrigerators.

Oh and one more thing, looking at the OP pictures, I think I reinstalled my relay backwards, would you agree?

If so, I think that could cause the new capacitor to burn and have no effect on the old capacitor (as it doesn’t work at all).
I guess I will switch it and risk a new capacitor to find out.

 

[nadogail]

HVAC & Refrigeration are, in many respects, the same trade.

 

[ALTEREGO]

Thank you Nadogail and Dagny, my Dayton 4Z123F grinder is working great now!

https://www.garagejournal.com/forum/showthread.php?t=475778