motor capacitor


Old 08-31-09, 02:49 PM
Thread Starter
Join Date: Nov 2004
Location: CA
Posts: 2,041
Received 0 Votes on 0 Posts
motor capacitor

What would be the implications of using a 5 UF/370 volts capacitor on a motor, when the motor calls for 6 UF/370 ?

The motor is the vent motor on a power vent water heater, so certainly if the motor speed or cfm was affected a lot, we would not want to do that.
Sponsored Links
Old 08-31-09, 03:08 PM
Join Date: Aug 2008
Location: Kansas
Posts: 233
Received 0 Votes on 0 Posts
This is a run capacitor and there is generally no tolerance allowed like in a start capacitor. Run capacitors are energized at all times while the motor is running and are critical at keeping the motors magnetic field level or stable. An improperly sized run capacitor is risky business, The motor could overheat and burn up, it could become noisy/vibrate and generally will not last long if they do run for a while.
Old 08-31-09, 03:34 PM
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
Received 1 Vote on 1 Post
Agreed. If a 5uf was called for and you temporarily substituted a 6uf it could work, but not the other way around.
Old 08-31-09, 05:46 PM
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Received 0 Votes on 0 Posts
That one of my golden rules with single phase motor with either starting or running capaitor always replace the same size or next size up but nothing under the manufacter specs for the capaitor sizing.

ditto with voltage rating as well some case you will see diffrent voltage rating as well.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

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