Union Graduate 1.5HP motor upgrade project

[minilathe22]

For the motor you want a 4 pole or 6 pole if you like doing larger items as it runs slower. Although you can make any motor run at almost any rpm with a vfd, the more poles it has the more torque it will have at lower speeds. If you are going through all the effort of swapping the motor then its worth getting one that is at least 1HP, more than 2HP the motor is probably too physically big to fit in the hump unless you lower the motor bracket somehow. The motor I have is an ABB 6 pole I got on ebay as a used item, I believe new these are around £400, new TEC motors of similar spec are around £150 on ebay. Probably a premium ABB motor is overkill for a hobby wood lathe. With secondhand motors some are dual voltage rated, but some older ones do not mention 240v at all, I would hesitate to purchase a motor that is rated high voltage only as it may not be easy to get it working on 240v.

As mentioned by several people before make sure your VFD can handle the current rating of the motor with room to spare, don't just use the power rating. The VFD I have is a Yaskawa CIMR-JCBA001010BAA. Be careful purchasing a VFD, many are 3 phase to 3 phase converters, which is probably not alot of use! you want to check its a single phase to 3 phase type. The ABB motor I have is M3AA90L-6. It is possible to fit the VFD below the motor so its all contained in the lathe, but then adjusting the settings is difficult! I opted to put the VFD in an old PC case where it can get lots of ventilation and protected a bit from dust. There are much cheaper VFDs online, many people have used them but usually complain about the quality of the manual/support.

 

[aebersold]

Thank you for such a detailed response, it’s a great help. I will look for a 1.5hp motor, but the difficulty is knowing whether it will fit. The original motor is a D80 frame, so I’m guessing that’s what I need to source to avoid unnecessary work ? I then need to source a control switch with speed control to fit into the existing switch plate housing.

 

[minilathe22]

I think mine is a D90 size (its in the part number) and its close to the inside of the cast iron "hump" but not touching. I have seen some Union Graduate lathes with a fan vent at this end. D80 size and 1.5HP sounds unlikely to be available but I could be wrong.

I fitting an emergency stop button in place of the original switch, and then I have a small box on a long cable from the VFD with the speed control, stop/start and forward/reverse rocker switch. I can then place it where I want depending on where I am working. I keep meaning to fit some magents to it. cat7 computer ethernet cable is 4 twisted pairs inside a metalic shield, ideal for connecting up multiple wires to the vfd.

 

[bigbigblue]

Hi Alex,
This is the motor I purchased : link
The vfd is a Schneider ATV12HU22M2, which I purchased as a clearance item (it was a one off)

 

[aebersold]

Thanks m/lathe, bbblue, that’s most helpful and throws in a few options. My brother will sort the electrical connections for me, I just need to be sure of the hardware and fit it. The motor in the link bbb looks well made and I like the option of moving the base position. I‘ll give the 6 pole and greater torque some thought too but they seem pretty expensive. Thanks again.