12" Delta Wood lathe, DC Motor and controller install, What size pulley should I use?

[Riparian]

Hello Everyone, first post

I have an old Delta 12" HD variable speed Wood Lathe. 130vdc PM DC Treadmill motor, 116ZY2-1. KB120 controller.

I know the controller is a little small, I good deal on it.

I haven't installed the DC motor yet. Thought I might bench test it and make changes to the control panel.

The final problem I have is which size V pulley should I use?
Keeping the treadmill flywheel
3" V pulley 220vac motor on the lathe now
38" from spindle center to V pulley center
5" spindle V pulley

I realize this question can get very complicated. Hoping someone worked out the best size to use already.
10" stock is max.

Would there be any advantage to mounting the DC motor closer to the spindle?

 

[Ulma Doctor]

If you were to make the drive pulley smaller than the OEM pulley, you could avoid running the motor at very low rpms and keep more torque at low spindle speeds.
I doubt that you would miss the very top end of the motor potential

albeit an apple to orange comparison, i used a 2.25” pulley on one of my Shenwai 1236 lathes, for the same reason of excellent low end torque .

the shorter the belt, the less power is lost in transmission
In general, If you can reduce belt length, more power can be delivered (or the less power is lost depending on how you look at it)

 

[benmychree]

You would want a top spindle speed about 2,000 RPM or a bit more.

 

[Riparian]

Mostly I want low RPM with good torque.
100-2000 rpm would be nice.

 

[Riparian]

I seen an old post of someone using a 1" pulley. I didn't see all the details but got me to wondering.

Is 1-2" size difference going to be noticeable?

 

[Ulma Doctor]

The problem with a 1” pulley is the belt arc.
If you are using standard v-belts, 1” may be too small of a diameter to work effectively.
Poly belts won’t have the same restrictions

 

[Riparian]

What did you do to center the pullies up? Planning to remove the old delta variable speed aluminum pulleys. Not sure how that's going to leave the motor and spindle pulley aliment.