Missing start cap on motor


Old 09-16-20, 08:41 PM
Thread Starter
Join Date: Sep 2020
Posts: 1
Received 0 Votes on 0 Posts
Missing start cap on motor

I was given a compressor motor with a missing start capacitor, I need help figuring out how to replace it,
The motor is a Doerr by Emerson Electric Model LR22132, Ref R10906bk 936, 60hz, 1phase, continuous duty, SF 1.0, Amps 15/7.5, LR amps 102/51, 120/240 volts Any help figuring out the start cap is greatly appreciated.
Ive been on some web sites that give formulas, but I am unsure of that. If any further info is needed, please ask.
Thank you in advance
Old 09-16-20, 09:03 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 60,886
Received 1,342 Votes on 1,240 Posts
Welcome to the forums.

There have been many requests for help with the infamous LR22132 motor. Unfortunately that number doesn't help identify a particular motor. I never quite understood it as it's used to identify many different motors.

The cap size will probably need to be computed.
The motor HP is required.
Old 09-16-20, 09:42 PM
Rough Rooster's Avatar
Join Date: Feb 2014
Location: USA
Posts: 428
Received 6 Votes on 6 Posts
Start capacitor sizing formula

2650 X Full Load Amps Divided by Supply Voltage = MFD

If the full load is not the locked rotor amps then increase MFD by 1/3

For hard start loads such as compressors or augers.

2650 7.5 (Running Amps) = 19,875/240 = 82.8 MFD add 1/3 (28) = 110 MFD
Should get you in the ballpark range to start motor.



Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: