View Full Version : How to tell if a motor is reversible...

02-26-2011, 05:12 PM
I'm still early in my learning on electronics.

I need to make a machine with a motor. I need to place the motor, and the best place for the motor makes the shaft spin the wrong direction.

How do I tell if the motor below can be reversed? The larger question is, how do I tell in general, ie with any motor?


Does anyone know of a smaller motor? It doesn't need to be as powerful, but more powerful than a Dremel. This has to be taken on a plane fairly often, and size/weight is a concern. The RPM of the shaft that the motor turns needs to be ~3000 RPM. I can accomodate faster/slower RPM motors by varying pulley sizes to an extent.

doctor demo
02-26-2011, 05:33 PM
The motor that You linked to can't be reversed or the description would have not stated the rotation as it did.
All three phase motors can be reversed.
How exactly to tell if a particular motor is reversible is a pay grade above Me.
A motor more powerful than a dremel and not excessive large would be a drill motor and most of them are reversible.


02-26-2011, 05:35 PM
The motor in your link only runs one way. CW.

Can you use a DC motor or is that out of the question?

02-26-2011, 05:41 PM
Well, the URL says 'Rotation CW'
So thats the first big hint its not reversable.
then it says: 'Motor Type: Shaded Pole'
IIRC, shaded pole can not be reversed, the direction is determined by notchs in the rotar. (So unless you wanna take the rotar out and turn it around..)

Also, 'HVAC' and 'Duty: Continuous Air-Over', Makes me highly suspect this is one of those 'To be used inside a fan, with the fans air passing over it to keep it cool' motors.

02-26-2011, 07:10 PM
It may not be reversible by wiring changes, but if you took it apart and reversed the field core it would reverse the rotation. May or may not be possible, but another question comes up- at 1/15 hp it's not very powerful, and at 1650 rpm or whatever it said, it has to be that large. Personally, I think that's the wrong motor for the power level and speeds you're looking for. By the way a decent dremel motor is probably at least that powerful- my dremel is rated at .95 amps which translates to about 1/6 hp in very rough terms. Too fast for what you want, but can be 'geared' down.

It occurs to me that a trim router might be a much better starting point. They are also very high speed motors, but you can use a speed control along with some reduction gearing, and they are generally very smooth and will have ball bearings for a long life. If your use is as low powered as you imply, you won't have any problems with it overheating at slower speeds, and physically it is much more compact. Other options are sewing machine motors, plug-in electric knife motors, or even those wand type drink mixers- those have a permanent magnet type motor, of which almost any one is reversible.

Almost all these options would require some hacking from you to be useful, but it's mostly going to be mechanical, as in how do I mount it, etc.

02-26-2011, 07:16 PM
Did you check at the Surplus Center? https://www.surpluscenter.com/electric.asp?catname=electricThey have several ccw motors in various horsepowers.

02-26-2011, 07:28 PM
It may not be reversible by wiring changes, but if you took it apart and reversed the field core it would reverse the rotation. May or may not be possible

Apon double checking, I was a little wrong, Shaded pole is when they wrap a shorted turn of a copper around part of each pole.

Basicly they are only reversable if you can rip out the entire field assembley and put it in backwards. Apparently they have very low starting torque too.

02-26-2011, 08:16 PM
But if it will, take a look here: http://www.robotcombat.com/products/motors_main.html I'd be surprised if you couldn't find something that would work there :-). Later.


02-27-2011, 02:50 AM
I have no idea what you are building but I have seen this done to reverse direction if it is belt driven, and that is to put a twist in the belt.

Bill Pace
02-27-2011, 09:44 AM
This little motor seems to fit your needs really well --- the rotation is CCW, rpm is to your specs, its really a well made little motor ... and can be variable speed with a common dimmer switch, its also cheap!