Start cap wiring for stirrer gearmotor

[StMarcos]

I have a gearmotor that will be used as a mash-stirring device. I ordered the start capacitor. Which two leads should be the power, and between which two should be the cap? Three wires, teal/blue, yellow, and black. I'm guessing that the little do-dad at the top of the pic, where the yellow wire runs, is the run cap. Not sure how this motor switches off the start cap once up to speed. If nobody is familiar with this color code, how do I go about finding out the right wiring schematic experimentally? I have a multimeter at disposal....

Cheers, etc!

 

[StMarcos]

Rough resistance between wires:

Blue to Black 19ohms
Blue to Yellow 10ohms
Black to Yellow 8ohms

Any help there?

 

[day_trippr]

From the resistance readings, I'm going with this: the Blue wire feeds the Start winding, the Black wire feeds the Run winding, and the Yellow is the common. Measuring from Black to Blue puts the Yellow node in the middle - hence the ~19 ohms is summing the two legs (8 +10).

So from that I think the Start capacitor should go in series with the Blue wire. But I also would expect that somewhere in that motor there should be a centrifugal switch that gates the Start winding...

Cheers!

 

[StMarcos]

Thanks d-trpr, will review the logic tomorrow when the mind is more sharp....

Yeah I imagine there is some way that the start cap switches off once up to speed. Can't deduce it at the moment but it's been years since I had to understand inductors and magnetic windings etc. Can't see too well deep into the stator as there's lots of grease packed into the end.

 

[StMarcos]

So, one side of the cap goes to blue, and the other side plus the black go to one side of the power in, and the yellow goes to the other side of the power in?

From the resistance readings, I'm going with this: the Blue wire feeds the Start winding, the Black wire feeds the Run winding, and the Yellow is the common. Measuring from Black to Blue puts the Yellow node in the middle - hence the ~19 ohms is summing the two legs (8 +10).

So from that I think the Start capacitor should go in series with the Blue wire. But I also would expect that somewhere in that motor there should be a centrifugal switch that gates the Start winding...

Cheers!

 

[day_trippr]

That's my SWAG, yes. For sure the yellow wire will be the return, but you may have to try connecting the start capacitor in both combinations (in series with the black and then the blue wires) to see if you can detect the presence of a centrifugal switch controlling the start windings. If there is one, the right combination should be readily evident.

I just had a thought: you may be able to detect a centrifugal switch by chucking the motor shaft in a drill and spinning it while checking the resistance from black to blue. If the switch opens that circuit will open, at which point you can check black-yellow and blue-yellow to see which side is the one that opens when you spin the rotor...

Cheers!

 

[StMarcos]

Wired it as above. Starts. Then stops. Then starts... basically pulses one sec on and two off.... perhaps the centrifugal switch is switching off the main power, and not the start cap? Or the cap, while charging up, allows power, but once charged and an open circuit, cuts off power? Thanks for the help!

 

[StMarcos]

Switched the blue and black, still thinking the yellow to be common. Ran for about a minute and stopped. Likely due to thermal overload, as the housing got bloody hot. Ideas on next steps?

 

[StMarcos]

Did some more testing. Managed to get the motor running for 3min with the power across the yellow and blue. Started with the cap in series with the black, but removed it after the motor started running. The was a spark when I removed it, which is odd as it should have been out of the circuit at this point. The motor ran more quietly after the cap was removed from the circuit. The centrifugal switch, which I cannot seem to locate, seems not to be working correctly. Case seemed to still get pretty hot, so I'm not terribly confident that this motor will cut it.

Seems that as this motor was only $20, I should be looking for somethings else. Ebay doesn't seem to be much cheaper than new for gearmotors, bison, leeson, bodine etc. Need maybe 250-400rpm and 1/20th horse. Looks like at least $300 if not $400. Can't figure out why they are so much $$$, as it's just a motor with a simple gear reducer.

 

[ClaudiusB]

Did some more testing. Managed to get the motor running for 3min with the power across the yellow and blue. Started with the cap in series with the black, but removed it after the motor started running. The was a spark when I removed it, which is odd as it should have been out of the circuit at this point. The motor ran more quietly after the cap was removed from the circuit. The centrifugal switch, which I cannot seem to locate, seems not to be working correctly. Case seemed to still get pretty hot, so I'm not terribly confident that this motor will cut it.

Seems that as this motor was only $20, I should be looking for somethings else. Ebay doesn't seem to be much cheaper than new for gearmotors, bison, leeson, bodine etc. Need maybe 250-400rpm and 1/20th horse. Looks like at least $300 if not $400. Can't figure out why they are so much $$$, as it's just a motor with a simple gear reducer.

Not all motors have centrifical switches build in.
Your motor could be a split phase with a permanent running cap.
What info is on the name plate?

 

[StMarcos]

It's this one:

http://www.herbach.com/Merchant2/me...uct_Code=TM98MTR3135&Category_Code=ACGEARHEAD

also

http://www.ebay.com/itm/HOWARD-INDU...ONTINUOUS-DUTY-115V-W-CAPACITOR-/130957602254

I got the one from h&r. Bought motor start cap from mcmaster.

Nameplate didn't have much info. Said it should require a 40uF cap (from the ad, not the nameplate). I bought a 50uF cap, thinking that if it started fine it shouldn't matter after that, as the cap would be switched out of the circuit. Maybe this is the run cap I am supposed to wire? Seems a bit large don't you think?

Recall that if I put the cap on the blue, and power bet the yellow and black, it would pulse run, say 1s on 2s off, sort of like it was switching off, but not the cap, but the power. The thing def. overheats with the cap in the circuit (cap on black, and power yellow and blue), but not so much with the cap removed after starting. I believe the little rectangle in the top of the pic I posted to be the thermal overheat switch.

 

[day_trippr]

Ah HAH! Did you notice the piece of paper in the eBay ad?

There's your wiring diagram...

Cheers!

 

[StMarcos]

Shoot I did not!