[How-To] Vfd on alliant milling machine

[Mheaton92]

So I have finally got myself a full sized milling machine. I have been tearing into it fixing what I can before I get that he garage wired up. My question is these fans. The motor is a 3hp 3 phase, I plan to run it on a 220 single phase to 220 three phase vfd. Any ideas for these cooling fans? Can they be connected as they are? I also thought of replacing them with 120vac fans the same size.

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[JimDawson]

From the way they are wired, the fans seem to be 230V single phase.

You could use the output relay in the VFD to drive another double pole relay to turn the fans on when the VFD is running the motor.

Or use the output relay in the VFD to operate a couple of 115V fans directly.

Or connect the fans directly to the 230V single phase on the input side of the VFD.

Or just leave them wired as they are, they draw so little current that the VFD most likely not even know they were there and the fans would probably run fine as long as you keep the frequency between 30 and 90 Hz.

The least cost method is just to try it and see how they work wired as they are.

 

[Mheaton92]

Thank you, I planned on doing speed changes with the mill and tucking the vfd away. So I will try that, I just wasn’t aware if it would cause any issues or not.


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[mksj]

Your head and mill look identical to the Sharp LMV and made be First Industries Taiwan, the motors as wired in parallel are as Jim indicated 220V single phase AC, when wired in series they are 440V. I would try to run them directly off of the VFD, they are there to cool the Reeves drive. Typically with the Reeves drive you leave the VFD at a fixed speed and use the mechanical adjustment for macro speed changes, that way the drive gets worn more evenly.