There are many dozens of these motors/gearmotors available for less than 20usd, often less than 10usd, on the web. Often found in microwave oven platter drives, BBQ rotisseries, metering/dosing drives, etc.
They are generally spec'd cw/ccw. The nature of the design. Random start in either direction. Upon stall will generally reverse. In most applications it seems that this quality is either not a problem for the purpose, or potentially an asset ... if the mechanism jambs for instance.
How can I determine which, if any, of these little motors will run consistently cw? I've tried reading up on the details. Surprisingly little clarity on this anywhere. The "timing" variety of these motors must run in the same direction, no? How is that accomplished? It's occasionally suggested that some types have additional windings for starting in other mode (shaded pole?) before spinning up to sync with line frequency. Some versions have three wires, instead of the more common two, with capacitor, and appear to be wireable to run in either direction consistently. Other constant direction types are said to have a form of sprag clutch on the upstream side of the geartrain (to minimize stress on the teeth) which pauses the startup in the "wrong" direction sufficient to induce the motor to reverse itself into the desired direction. But what search term would I use to identify these types?
If anyone can provide a link, or means to query such a link, to any inexpensive synchronous gearmotor of approx 3rpm that will always run CW I'd be most appreciative. Since this speed is common to microwave turntables and rotisseries it is common as dirt and subsequently cheaply had.
Thanks so much for any suggestions or synchronous motor enlightenment!
They are generally spec'd cw/ccw. The nature of the design. Random start in either direction. Upon stall will generally reverse. In most applications it seems that this quality is either not a problem for the purpose, or potentially an asset ... if the mechanism jambs for instance.
How can I determine which, if any, of these little motors will run consistently cw? I've tried reading up on the details. Surprisingly little clarity on this anywhere. The "timing" variety of these motors must run in the same direction, no? How is that accomplished? It's occasionally suggested that some types have additional windings for starting in other mode (shaded pole?) before spinning up to sync with line frequency. Some versions have three wires, instead of the more common two, with capacitor, and appear to be wireable to run in either direction consistently. Other constant direction types are said to have a form of sprag clutch on the upstream side of the geartrain (to minimize stress on the teeth) which pauses the startup in the "wrong" direction sufficient to induce the motor to reverse itself into the desired direction. But what search term would I use to identify these types?
If anyone can provide a link, or means to query such a link, to any inexpensive synchronous gearmotor of approx 3rpm that will always run CW I'd be most appreciative. Since this speed is common to microwave turntables and rotisseries it is common as dirt and subsequently cheaply had.
Thanks so much for any suggestions or synchronous motor enlightenment!
