Hack for dead motor on old Vacuum Pump

[EpicenterBryan]

Hey guys,

Thought you might get a kick out of this. The motor died on my vacuum pump and it was an odd RPM (950). The replacement motor I found on Craigslist rotated in the wrong direction (CW not CCW) and was 1725 RPM. I discovered it was possible to reverse direction of the motor by swapping 2 wires inside. I figured there was a way (other than swapping the motor end for end and changing the mounting scheme) but I newer had a need to do anything like this. This may only work with really old electric motors like this one that have separate starting coils and run coils.

Since the replacement motor RPM was faster than the old one, and the old motor had a small pulley (not really possible to make it smaller) I installed an intermediate shaft and did a pulley reduction.

The replacement motor also had a variable pulley installed (that was stuck in it's current position) but it could also be adjusted if I needed to get the overall RPM with belt reduction closer to the desired speed. A variable pulley is interesting in that there are two plates with angled faces pointing toward each other, that when adjusted together closer, cause the belt to see a larger diameter, and when adjusted further apart, the belt sees a smaller diameter pulley.

Check it out...

[Prestofan]

Hi Mr. Epicenter:

That pump was originally in a player piano. The motor had a bad spot and sometimes when shutting off, it would not start again unless you twisted the wheel a little. Made it cumbersome when it was installed in the garage away from the lathe.

Your old friend

[EpicenterBryan]

That pump was originally in a player piano.

Alan, Good to hear from you!
You are missing out on some fun here in Oregon.

So, a player piano? Interesting.
I also got a second one. The one I fixed is in front in the photo. The second one runs the other direction (clockwise) and has a 1725 motor on it already. Not sure if that's the right one or not. It looks like a much newer motor. The vacuum is low and I think that one needs some new flapper valves fashioned so I figured I would dive into it at a later time.
Did the second one come from you too?

Bryan

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[Prestofan]

Umm: unless you changed to mounting board/base, I think the second one was mine. I didn't know that Steve had two, or I'd forgotten. I think he had three pumps - the little 9 or 10" square model found in many old lathes. The old piano pump really had a great amount of air movement which is what is needed.

Great to hear of your improvements and your work on a DIY stereo head.

Alan