me wrote:
Sam Goldwasser wrote in
:


"w9gb" writes:


"leoJ" wrote in message
groups.com...

Homer J Simpson wrote:

"leoJ" wrote in message
legroups.com...


Have a bench grinder that was given to me and runs fine if you
spin it up by hand - the capacitor is missing. Is there a way to
determine what size/part no. capacitor will work with a 115V
60Hz Single Phase motor?

HP?

3/4 HP, 3600 RPM


Likely a motor start capacitor.
http://www.cde.com/new/catalog/motorstart/

CDE motor start capacitor catalog page (download this - right mouse
click - Adobe Acrobat)
http://www.cde.com/catalogs/PSU.pdf

I am looking at a NOS Mallory motor start capacitor on my bench --
it is rated at: 108-130 mfd at 250 VAC

Application Guide
http://www.cde.com/catalogs/AEappGUIDE.pdf

If it's used only for starting.

Easiest test would be to spin it up by hand and then use a multimeter
to check for voltage across the wires where the cap would go. If you
see full line voltage, it's a run cap.

snip waste text


Most bench grinders I've seen use a motor run capacitor.



But if he has to spin it to start it, that would imply it's just a
starting capacitor. Can you hear an audible click as it picks up speed
and again just as it slows to a stop?