Hi,

I acquired a Hercus 9C several months ago. I am limited to single phase at home but have a few options for motors.

1) I have the original 0.5hp 3 phase motor, which assuming is ok, I could power it via a VFD. I can't do this right away, as I have other more pertinent expenses, but I have seen suitable VFD's for about $150.

2) I have a single phase 2840rpm 1hp 240v 2 pole motor which is reversible but will need to experiment with pulley ratios and may even need another countershaft since the motor pulley will end up being a bit small for the correct countershaft speed. (not impossible, could employ a simple 2 stage pulley belt drive reduction from the motor as per a lot of drill presses)

3) I also have this treadmill motor, 1.5hp, 5700rpm at 180VDC, and the PWM motor controller it came with (I am capable of modifying it for my purposes though it is a task that will require time and effort) Or I could even salvage a step down transformer and a rectifier and smoothing caps to get a suitable voltage to get down to the 1400 odd motor RPM that the lathe is best run at.

I am not an expert in DC motors, but I suspect that running the motor at 1/4 of its maximum speed is going to yield less than ideal power delivery??? Is there a simple or rule of thumb method to calculate the resultant available motor power at the reduced speed? I am currently focusing on feasibility of option 3, and if that is not do-able will take option 1 or 2.

Thanks for any thoughts or advice.

Steve.


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