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Rotisserie motor DOA


 
With some of the gears off, make sure that the motor still runs (be careful not to shock yourself). And/or, do a continuity check with an ohmmeter to see if the coil has gone open. Unfortunately, If the coil is open, the motor is toast.
 
Keith Jenkins said:
With some of the gears off, make sure that the motor still runs (be careful not to shock yourself). And/or, do a continuity check with an ohmmeter to see if the coil has gone open. Unfortunately, If the coil is open, the motor is toast.
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The nice thing is those motors tend to be very cheap and easy to find AC asynchronous type motors
 
This is a shaded pole motor, really simple mechanically but somewhat difficult to understand electrically. Here's a good video if you want to dive in.


I'm 90+% certain your problem is mechanical, somewhere in the gear train. These motors don't have a lot of starting torque but as long as the rotor bearings are good and the stator coil is good, your problem is not electrical but mechanical. I would start by removing the gear train from the equation and, one by one, go from there. Best wishes and good luck!
 
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Hi All,
Thanks for all the inputs. Indeed, after taking it apart one gear after another and cleaning each one, and then reassembling the gear train, the motor started to turn. Wow. Amazing. You guys are really gurus. Thanks!! Oh BTW, what is a recommended lube that I can use for the gears and how to apply?
 
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I have begun experimenting with this on mixer repairs. Seems to have a slightly lower viscosity than what I'd been using allowing quicker "spread" when the machine starts up. I think it "flows" a little better on the gears and bearings and they seem to run a tad quieter. Also IIRC has a slightly wider temperature operating range than previously. I'm not sure long term so on machines I've used it in I've increased my warranty for lubrication failure to 2 years. But so far after 6 mos of using it I'm getting very good results. I did it because I noticed KA has also quietly shifted to a lithium type grease (still nowhere near the quality I'm buying) but holding up better than what they were using. So, I am watching performance carefully on those machines. https://www.amazon.com/dp/B0CGRHBZRM?tag=tvwb-20
 
Cody Bratton said:
What can a guy to to make these things really spin? Like chucking the drippings all over type of speed? lol
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Not happening with this type of motor. These motors are typically used for cooling fans and low power applications. The only reason they can spin the weight that they are rated for is because of the torque multiplication that comes from the gear ratio. In general, AC motor speeds are frequency related and again, in general, 1800 or 3600 RPM are common speeds found with a 60Hz AC input. So if the motor spins at 1800 RPM and it is geared down to a 3 RPM output, that is a 60:1 gear ratio, or torque multiplication of 60x, assuming 100% efficiency.

I suppose, if a guy was hell-bent on doing this, a VFD (variable frequency drive) could possibly be used to multiply the frequency to maybe 180Hz, but the motor wouldn't last very long. It would be easier to buy a DC roti motor and drive it at a higher voltage than it is rated for. I've done this with my pizza oven, to spin the stone faster (turned out to be a bad idea: the stone moves too fast to pick up the heat from the burner and actually runs cooler than it did at a slower speed).
 
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Ed P said:
Not happening with this type of motor. These motors are typically used for cooling fans and low power applications. The only reason they can spin the weight that they are rated for is because of the torque multiplication that comes from the gear ratio. In general, AC motor speeds are frequency related and again, in general, 1800 or 3600 RPM are common speeds found with a 60Hz AC input. So if the motor spins at 1800 RPM and it is geared down to a 3 RPM output, that is a 60:1 gear ratio, or torque multiplication of 60x, assuming 100% efficiency.

I suppose, if a guy was hell-bent on doing this, a VFD (variable frequency drive) could possibly be used to multiply the frequency to maybe 180Hz, but the motor wouldn't last very long. It would be easier to buy a DC roti motor and drive it at a higher voltage than it is rated for. I've done this with my pizza oven, to spin the stone faster (turned out to be a bad idea: the stone moves too fast to pick up the heat from the burner and actually runs cooler than it did at a slower speed).
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Agreed. The real advantage of shaded pole motors is that they are pretty inexpensive to manufacture. They aren't particularly efficient, and usually run rather warm. I have run across a few that had open coils, which is why I suggested that the motor's operation be confirmed before going much further. Now that it is known that the motor works, cleaning and lubricating the gear train is the next move. Also agree that these motors are fixed speed induction motors, running a multiple of the line frequency (in this case, 60Hz). So speeding up a motor of this type for this application would likely prove cost prohibitive.
 
I just bought this unopened NOS rotisserie recently.
I don’t really want to open it and find out myself, so what are the odds this doesn’t spin if I were to fire it up at this point?

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Yup, only God knows until someone plugs it in and runs it. Personally, I think it will be fine, but then I don't go looking for trouble, I generally wait for trouble to find me.
 
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