AC Motor Cap Question

Capacitor start motors have an internal switch to disconnect the capacitor after the motor comes up to speed. Perhaps this switch is bad on the motor. You can usually hear a click when the motor slows down that indicates the capacitor has been switched back in.

:OK, so I have this AC motor that I would like to use in a project. It :has a partial label that shows the connections. It has 3 wires, black, :red and blue. The diagram shows a cap between the red and blue. One :connects the 120 VAC to the black wire and either the red OR blue to :start the motor CW or CCW. : :OK now the question is what is the value of the Cap? I have tried a :couple of starter caps I have here, but they seem to retard the motor :after it starts up, limiting the speed substantially until I open the :the cap connection. The motor will then purr along nicely. : :Motor specs from label; : :VonWeiss Gear Company :Model ???????0-1295-6 (? are scraped off) :115V 60Cy 1 phase :60rpm output :1.3 ???ap (? are scraped off)(I thought this might be 1.3 uf cap) : :BLACK------------ L1 To Reverse :RED------¥------- L2 Interchange :BLUE-----¥ Red & Blue Leads : :(The Yen signs are where the cap is shown connected between the Red and :Blue leads.) : :Any usful info would be greatly appreciated. : :Thanks, : :- Tim -

Von Weise Gear Co was apparently bought by Hawker Siddeley back in 1988 and then it was incorporated into the Fasco Industries group.

Looking at the last link it would appear that Fasco is now part of the Regal Beloit group but if you go there they don't show Fasco as one of their brands.

I would suggest you read the Fasco Facts document under Distributor Services and you may get some clues. Failing that, try contacting Fasco for assistance.

OK now the question is what is the value of the Cap? I have tried a couple of starter caps I have here, but they seem to retard the motor after it starts up, limiting the speed substantially until I open the the cap connection. The motor will then purr along nicely.

Motor specs from label;

VonWeiss Gear Company Model ???????0-1295-6 (? are scraped off)

115V 60Cy 1 phase 60rpm output 1.3 ???ap (? are scraped off)(I thought this might be 1.3 uf cap)

BLACK------------ L1 To Reverse RED------¥------- L2 Interchange BLUE-----¥ Red & Blue Leads

(The Yen signs are where the cap is shown connected between the Red and Blue leads.)

Any usful info would be greatly appreciated.

Thanks,

- Tim -

Is this a ceiling fan? Cap is there for speed control.

Not this one. It is a PSC motor, so the 2 windings provide the start action, and the cap is always connected.

- Tim

No it is a gearhead motor. The cap is needed to change the phase of the=20 second winding to start the motor. The motor is a PSC type that needs=20 the cap to be connected at all times.

- Tim -

OK I used my magnifier to get a better look at the label.

VonWeiss Gear Company Model ???80-1295-6 ????t Duty Ser E73 (? Are Scraped Off)

115V 1.3 Amp 60Cy 1 phase =20 60rpm output 1/12 Horsepower =20 BLACK------------ L1 To Reverse RED------=A5------- L2 Interchange BLUE-----=A5 Red & Blue Leads =20 (The Yen signs are where the cap is shown connected between the Red and=20 Blue leads.)

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I scrounged around my junk collection and found a 6uf 750V cap that=20 seems to work great. It's a bit big, being a 750v and all, but it works.

Thanks to those whom replied.

- Tim -

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--=20 Email - snipped-for-privacy@nospam.nbnet.nb.ca (remove the nospam part)

And If I Forgot To Mention My Location, I'm In The Fredericton Area

I see you found a suitable capacitor value in your other post. Without finding some online info regarding the original or similar application for the motor, and subsequently, the original value for the capacitor, you're limited to trying different cap values by trial/error. There was a guide chart for PSC motor cap values referenced quite a few years ago, here in SER, but I have no recollection of where that chart was.

A source for AC capacitors is a retailer that stocks replacement parts for ceiling fans. Some of the fan AC caps have three leads, for two capacitor values within one case (adding values in parallel).

The value of the capacitor used with a PSC motor can affect slight changes in the motor's speed and torque, and to a greater affect, the operating temperature. The slight speed and torque changes may not be significant to the application (particularly with gear reduction), but the operating temp could be more important, as far as insulation or bearing lubrication breakdown.

-- Cheers, WB .............

OK now the question is what is the value of the Cap? I have tried a couple of starter caps I have here, but they seem to retard the motor after it starts up, limiting the speed substantially until I open the the cap connection. The motor will then purr along nicely.

Motor specs from label;

VonWeiss Gear Company Model ???????0-1295-6 (? are scraped off)

115V 60Cy 1 phase 60rpm output 1.3 ???ap (? are scraped off)(I thought this might be 1.3 uf cap)

BLACK------------ L1 To Reverse RED------¥------- L2 Interchange BLUE-----¥ Red & Blue Leads

(The Yen signs are where the cap is shown connected between the Red and Blue leads.)

Any usful info would be greatly appreciated.

Thanks,

- Tim -

Thanks for your thoughts on this. I will certainly be watching for=20 overheating while experimenting with this.

I did find a Fasco product listing that had similar PSC motors listed=20 and the caps where all in the 4 to 10 uf range. That's why I used that 6=20 uf one, I figured it would be close enough.

I do recall the cap that was on this motor when I first saw it 10 years=20 ago, and it was about 1/2 the size as the one I have on it now. I am=20 continuing to look for that one for the permanent setup.

- Tim -

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When I was testing a variety of small Oriental Motor PSC types (about 20-60 watt sizes), I found that there didn't seem to be any solid size-to-value relationship for the manufacturer's recommended capacitor values.

Although OM may have been concerned with the motor's speed matching their published specs, that wasn't of much concern to me. I found that with one specific model, the recommended 2uF value made the motor run considerably hotter than a 6 to 12uF (by mesurement, not just a guess), but I didn't check to see what the change in speed was. I believe the speed change was very little, as it wasn't audible or otherwise noticeable (aside from the gearbox being a 90:1 reduction). The motors were all TEFC totally enclosed fan cooled, or no fan models, so the excess heat was just power wasted, and could be detrimental to the service life of the motor.

When dealing with gearhead motors, starting and running torques are less significant, due to the torque multiplication by the gear train. Exact output speed wasn't critical for my applications since I was using belt/pulleys to transmit power from the gearhead to the machine parts.

-- Cheers, WB .............

I did find a Fasco product listing that had similar PSC motors listed and the caps where all in the 4 to 10 uf range. That's why I used that 6 uf one, I figured it would be close enough.

I do recall the cap that was on this motor when I first saw it 10 years ago, and it was about 1/2 the size as the one I have on it now. I am continuing to look for that one for the permanent setup.

- Tim -