I have a couple of motors that I want to use for a project, but they run the wrong direction. Any way to reverse the rotation? (Yeah, I know. I "could" just physically turn the motor 180*. But it complicates the planned mounting procedure.)
Also, will one of the "router" speed controllers slow the rotation on any motor that doesn't have a capacitor start?
This question would be good over on rec.crafts.metalworking as it comes up often and they is a good page covering motor aspects such as this.
It does very much depend >I have a couple of motors that I want to use for a project, but they run
Size of motors? Geared? Constant speed? Big motors (1/4 hp + usually) with extra connections can be reversed. Those with only two connections usually can't. Speed control must be used with caution for overheating. Running a motor for a long time under load at low speed that is not a ceiling fan motor can really heat it up.
Most single phase induction motors have two windings - the start winding and run winding. The 1/4 - 1/2 hp size range usually have the start winding is connected via a centrifugal switch, so it cuts out when the motor reaches run speed. You can tell because there is an audible click when the switch operates. An induction motor will run either way once you kick it off, so you can make it start either way by reversing the connections (phase) to the start winding with respect to the run winding. Usually this must be done inside the motor terminal box.
A capacitor start motor (usually bigger - 1hp+) is obvious because there is an extra "box" on the outside of the motor housing the capacitor which connects to the start winding. The direction of these can be reversed by reversing the phase of the connections to the capacitor with respect to the run winding.
Either way, it's not really a job for the amateur - you probably should get a professional to do it for you.
Dave
So its not just a matter of reversing the connection of common and hot in the motor connection? but must be done further in the motor?
No, that won't do anything because the two windings are still "in phase" - you have to reverse one winding and not the other - ususally inside the motor. It doesn't matter which one you reverse, but the start winding is usually set up to be changed. Dave
No. But if it's reversible there is often another spade in the terminal box that you connect to the hot.
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