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PM1236 lathe motor problems

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cwheat

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#1
Hello all,
I became the proud owner of one of Matt's lathes about a year ago. Have used the machine very little since then but began having problems with the motor starting about 2 months ago. It had the original 220 volt single phase Chinese motor on it from the factory. It was having intermittent problems with start up and getting up to speed like a centrifigal switch not working or windings fighting each other. I got in touch with Matt and he was quick to suggest replacing the motor after a few trouble shooting tests were done. I opted to upgrade to the Baldor American made motor when I was offered the chance to do so. Matt thinks these problems are mostly due to the original being Chinese built. Now to the dilemma. After hooking up the new motor as per Matts instructions it is running the wrong way depending on the selection of the control lever. In other words when you push the lever down the spindle runs backwards or clockwise looking at the spindle. When the lever is pushed up the spindle runs the other way. Just wondering if any one has had any of the same problems when converting to the American made motor from the Chinese one. There is only a couple of ways the machine should be doing what it is doing. One is that the original wiring on the control switches, magnetic starters, or internal motor wiring was backward in some way or the new motor possibly has the external connector wires mislabeled which would not seem likely to me. I have contacted Matt but being on the weekend am not looking to hear from him until next week. I was just wondering if any one else had had any of the same problems as I have described. I am not an electrical person but do understand the basics. Being a new machine under warranty, I am going to wait for Matt's direction before swapping wires on the motor leads or changing starters to the other rotation to fix the problem. If anyone has had any similar experiences I would appreciate your input.
 

ttabbal

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#2
If the new motor is single phase you might not be able to reverse it easily. 3 phase is easy, swap any 2 wires. You might try searching for the model number of the motor, but it isn't likely to be as simple as a couple wires.
 

Dave Paine

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#3
The motor normally has a diagram on how to wire the motor. This may be on the outside of the motor or the inside of the terminal box.

You mention the lever on the spindle does get the motor to run either clockwise or counter clockwise, so your motor has been designed to run in either direction. You just need to switch two wires in the terminal box, but without a diagram hard to say which wires to switch.

The GE single phase motor from my Southbend Heavy 10 to illustrate.

Low volt means 120V, High volt means 240V.

This motor states to change T5 and J10 to reverse direction.

GE_motor_wiring_diagram_terminations_only_2972.jpg

The wires from the motor should be marked/labeled on the insulation. I added some markers to my wires since easier to read than the markings on the insulation.

Southbend_Heavy_10_motor_wires_marked_new_box_2984.jpg

You need to trace the wires from the levers up and down position back to the motor to determine which two wires to interchange.
 

Silverbullet

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#4
If your end plate is reachable on the motor you just change it there , the ends are marked on the board there. By just changing the two wires it will be set for your lathe. Usually they have spayed connector male on motor female on wires .
 

mksj

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#5
The motor problems you were having with the original Chinese motor are pretty common, usually the start capacitor goes but in a few cases the centrifugal switch can become faulty. The Baldor motor should be a substantial improvement. There are also a number of individuals that end up with a 3 phase motor and a VFD.

Would help if others just reviewed the replacement motor information available on the PM site, yes it is a reversible motor. The site provides the wiring diagram and instructions. If the motor is running in the opposite direction you want, then you would just flip (Interchange) the connections for motor wire 8 (Z1) and motor wire 5 (Z2), see the attached information posted at the PM site. One could change the connections at the motor or swap the two connections at the terminal strip in the control box.

single phase motor wiring.jpg
 

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Dave Paine

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#6
Would help if others just reviewed the replacement motor information available on the PM site, yes it is a reversible motor. The site provides the wiring diagram and instructions.
I would not expect folks responding to the post to reference the PM site if the original poster had not referenced the site. The original post did not state if he had referenced the PM site. I did not consider going to the PM site.
 

mksj

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#7
The title states PM1236, I do not know of any other manufacture that uses this designation for their lathe. All I did was look up the information, and Kudos to Matt for having all the documents online and clearly described. Needless to say, you are correct in your recommendation in that the only change required is to switch two wires to flip the rotation. I just added which two wires.
 
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