Vintage Delta Start Capacitor Problems.

Sep 22, 2008 26 Replies

If you click on (maybe double-click) the part number in the catalog listing, the data for that part number will appear in the pane on the left side of the browser screen. In that data will be a drop down box that allows selection of a specific capacity range. As I recall, one of the selections is the exact capacity you originally reported. When you select it, the capacitor part number will change to the one for that capacity.

Tom Veatch Wichita, KS USA

Yes, I double click the PN and it show the capacitor spec. I believe that's the one I should buy.

I did not go to the trouble of disassemble the motor as suggest by some woodworks here to find if the switch is the problem. Anyway the switch is mounted externally. I just tested the capacitor by shorting it as suggested by Doug. Thank you and everyone.

I ordered the capacitor from McMaster-Carr this morning: PN# 7245K112 AC Motor-Start Capacitor 216-259 Rating, 1-7/16" Case Diameter, 110-125 VAC. It's exactly the same spec. but 1/16" larger in Diameter and the capacitor casing is slightly larger anyway.

Thanks Doug, I really appreciate it.

Can u give me the rating for a running capacitor for a 3 phase motor running on single phase current?

Ballpark value is 70mfd per kilowatt but be sure these are oil-filled RUN capacitors. Basic hookup only gives maybe 1/4 to 1/3 of motor's rated power.

Better is a setup using a potential relay and a start capacitor in addition to the run capacitor - look on Youtube for 1 phase to 3 phase potential relay

Better yet (if you have the parts) is a larger 3 phase motor hooked up to effectively be a rotary phase converter. One of the "1 phase power to 3 phase motor" videos shows how. If the motor used as the "phase converter" is large enough, it can run the target motor near its rated power.

Or spend the $$ to get get a 1 phase to 3 phase VFD - which none of us ever wants to do - and not likely to be found at anyone's yard sale :-(

Look here:

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Or search Youtube with this phrase: Three Ways To Run A Three Phase Motor On Single Phase

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