# Electric Motor Problem



## Billh50 (Sep 11, 2016)

I received a motor for my bandsaw. I finally got around to hooking it up and it runs in the wrong direction.
It is a 110/220 induction motor with the following leads. Currently wired for 110. Can this be made to change direction ?

White & Yellow together and Red & Black together


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## TOOLMASTER (Sep 11, 2016)

i'm going to with no if those are the only wires


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## Billh50 (Sep 11, 2016)

That's what I thought. Thanks anyway. Guess I will look for another motor.


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## David S (Sep 11, 2016)

Bill can you supply more information before you throw this out?

David


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## Tony Wells (Sep 11, 2016)

Some motors are difficult to reverse. Those that are put on air compressors, for example. Since they will always run the same direction, for all their life (in the mfg view) they save a couple of bucks not running the windings out where we can work them. That doesn't mean you absolutely can't, just that it's probably going to require a motor shop, and some motors aren't worth the cost/trouble. Plus many compressor motors are 3450 RPM, and that doesn't work for everything.


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## jim18655 (Sep 11, 2016)

How about a picture of the name plate?


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## TOOLMASTER (Sep 11, 2016)

when you say together do you mean wire nut or something like this??

https://dewhite04.wordpress.com/201...e-the-drive-on-a-12hp-split-phase-240v-motor/


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## Billh50 (Sep 11, 2016)

They are wire nutted. It was a bit larger than the one that quit. Looking at the front of the motor it turns CCW and I need CW. It is a 1hp. Will get a photo of the tag and the motor tomorrow morning.


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## TOOLMASTER (Sep 11, 2016)

can you reverse mount it?


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## Billh50 (Sep 11, 2016)

I am not sure if I can.....will see tomorrow. I was just a bit too tired to look at much else tonight.


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## Ulma Doctor (Sep 11, 2016)

Hi Bill,
i don't know for sure if it will make your motor spin in reverse, but it is worth an experiment if you dare:
Black & White as one pairing
Red & Yellow the other pairing
power it up but be ready to pull the plug if there are any strange noises


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## Billh50 (Sep 12, 2016)

OK..took a look at maybe reverse mounting the motor. Nope! Found 2 other motors while rummaging through a pile in the corner. One has no tag as it fell off so I don't even know the HP or RPM. The other is a 2hp and 3450 rpm (I think) which is too much for anything I own. Even the one I tried to mount is a bit much for what I have. But beggars can't be choosers. And here is a photo of the tag on the one I tried to mount.


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## JimDawson (Sep 12, 2016)

It is probably possible to reverse the rotation of that motor, but you have to open the motor and bring out the start winding wires so they can be reconnected in the correct relationship to the run windings.  A local motor shop might be helpful.


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## Billh50 (Sep 12, 2016)

Well with no money for stuff like that I guess it will sit with the others til someone needs one. I will keep my eyes open for another motor as all I really need is a 1/2 hp.


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## talvare (Sep 12, 2016)

Bill,

I have an idea that may work. Not sure because I've never tried it. But, considering that electric motor  rotation is determined by the rotation of the magnetic field pulling the rotor around, I'm thinking that if you remove the end bells and reversed the stator, it may reverse the direction of rotation. But, if you decide to try this, you need to make sure that the rotor bars are still properly aligned with the ends of the stator bars.  If they aren't properly aligned, the motor will run hot and probably at reduced efficiency. Rotors in electric motors try to find their "electrical center". This is probably not an issue with the design of most modern small single phase motors, but I have worked on many larger three phase motors that were designed with a certain amount of "rotor float" so that the rotor was allowed to find it's electrical center when in operation. There was enough float in some of the rotors that drive sheaves couldn't be aligned until the motor was running.
Just some food for thought.

Ted


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## David S (Sep 12, 2016)

Billh50 said:


> Well with no money for stuff like that I guess it will sit with the others til someone needs one. I will keep my eyes open for another motor as all I really need is a 1/2 hp.



Bill are you able to take off the end bell that has the terminations to both windings?

I am thinking that there must be a way to reverse it if you can get at the connections to the start and run windings.

David


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## Billh50 (Sep 12, 2016)

I don't trust myself enough with doing something like that. But I appreciate the thoughts and help. I will take a photo of the wires on the one I have no idea what the HP or RPMs are though. I think it has more wires but not sure. Will check tomorrow.


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## David S (Sep 12, 2016)

Ok Bill we understand.  This is a family forum and I would do anything to help my family.  If you don't feel comfortable opening it up that is fine.  Sounds like you don't have lots of cash to throw around so I am sure some one on this site can help.

David


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## Mark_f (Sep 12, 2016)

Bill,

That motor is not reversible without reconnecting the windings ( according to the tag). It can be made reversible most likely and fairly easy. Back in the 70's I rewound motors and armatures. I just changed one for myself not long ago. If you were closer , I would be glad to do it, but the shipping on those motors is horrible.

I don't know if you are comfortable trying it with some photos and guidance .

I did one last year when I built the Bonnelle grinder. There is a write up on it in that thread.


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## Billh50 (Sep 13, 2016)

Well it will have to wait til next week anyway. I won't be around for a few days  starting tomorrow. I will try and find the thread and bookmark it.


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## TOOLMASTER (Sep 13, 2016)

http://css.wsu.edu/wp-content/uploads/2012/09/Motors1.pdf


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## Billh50 (Sep 13, 2016)

Thanks Toolmaker.
That made it look a lot easier to understand. Will try that.


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## JPigg55 (Sep 13, 2016)

Here's a YouTube video on reversing non-reversible induction motor.


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## talvare (Sep 13, 2016)

JPigg55 said:


> Here's a YouTube video on reversing non-reversible induction motor.



Bill,

This video describes what I just said to try. I'm glad that JPigg55 posted this because I wasn't sure myself. Give it a try.

Ted


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## Billh50 (Sep 13, 2016)

Ted,
I see what he did but still not sure if that will work with this motor because it has an external fan in the back to cool off the motor. Either way I will check everything better when I get back next week. I am going to be away from tomorrow til Monday.


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## John Hasler (Sep 13, 2016)

Billh50 said:


> I see what he did but still not sure if that will work with this motor because it has an external fan in the back to cool off the motor.


Depends on the type of fan.  Some centrifugal designs work fine in either direction.


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