What pulleys to use for a milling machine and VFD.

Ian SC -I did that with a big cut-off saw when the motor gave up. Just use the defunct motor as a countershaft and drive it , via belts or whatever. Lasted better than expected, must have been good bearings.

I see what you mean now!

It would be easier just to start again and build a new motor / pulley assembly as there is so little room on the current one.

Gordon, the bearings in the old motor would probably out last the new motor, also by using that system you can adjust the speed up or down as you like. There is a safety thing there to, the motor is mechanically isolated from the drive so that if there's a jamb up, the belt slips. Ian S C

Would this motor be ok?

http://m.ebay.co.uk/itm/3-Phase-Electric-Motor-1HP-0-75kw-1400rpm-80-frame-/110912538780

That motor looks fine. I know nothing of the seller and I have no idea whether its a good price. It does state that it is OK with VFDs.

I could not say whether its OK for your machine though as I dont know enough about the space available or any of the other details regarding its installation.

I have just been trying to upload some video to YouTube so I can put a link here showing how a very ordinary and old, 1450rpm (Hoover) motor works with a VFD. With 3:1 belt reduction I have a 38 to 1250RPM speed range (4 to 130Hz), and at 20Hz I have more than enough torque to cut a 50mm diameter spotface on aluminium (using a spigoted flycutter with a 14mm wide cutting edge.

Ian

Excellent, I just watched your video.

Do we think these style pulleys would be ok? They are the timing belt style.

You can click on the picture for a bigger one.

http://m.rapidonline.com/ProductSearch/ModuleDetails?ModuleCode=71294

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Chris,

Those appear to be very small pulleys

MichaelG.

Yes your right, I think that's the wrong link!