Replacement of Home Air Conditioner Run Motor Capacitor

Thread Starter

Dave Kovensky

Joined Jul 25, 2010
3
My home central air conditioner may have a bad Run Motor Capacitor and require replacement. The present capacitor is an Ultramet RA2000/37 (505+806) rated at 80/5 mfd and 370 VAC.

In all my searching on the internet, I was unable to find a replacement with those exact ratings. I did find and ordered a TopTech TT-CAP-60/5 mfd and 370 VAC Run Motor Capacitor.

Since the suppliers advise to replace a bad capacitor with a new unit having the same ratings, I am concerned about going from 80 mfd to 60 mfd. Please advise if this would be a problem.
 

Wendy

Joined Mar 24, 2008
23,396
I'm not sure, but it might be. We have enough people here I suspect we'll get a good answer shortly. I do know the capacitor is to help start the motor.

Have you contacted the manufacturer.
 

Thread Starter

Dave Kovensky

Joined Jul 25, 2010
3
Thanks for your suggestion about the Grainger 2MEG2 capacitor. I did look it up and even though it was listed as 80 mfd, I noticed that its physical size is considerably smaller than the 60 mfd I already ordered. My 60 mfd capacitor is about the same outside diameter but is 3/4 inches longer. Apparently mfd is not directly related to capacitor volume but I will wait for more inputs on this issue before replacing the capacitor. I replaced the original single 30 amp contactor which had badly burnt contact points with a dual 40 amp contactor and my HVAC seems to be operating okay. I planned on changing out the capacitor in the hope it would prolong contactor contact points as the 30 amp contactor was only a few months old.
 

Thread Starter

Dave Kovensky

Joined Jul 25, 2010
3
Thanks for your suggestion about the Grainger 2MEG2 capacitor. I did look it up and even though it was listed as 80 mfd, I noticed that its physical size is considerably smaller than the 60 mfd I already ordered. My 60 mfd capacitor is about the same outside diameter but is 3/4 inches longer. Apparently mfd is not directly related to capacitor volume but I will wait for more inputs on this issue before replacing the capacitor. I replaced the original single 30 amp contactor which had badly burnt contact points with a dual 40 amp contactor and my HVAC seems to be operating okay. I planned on changing out the capacitor in the hope it would prolong contactor contact points as the 30 amp contactor was only a few months old.
Since I posted the above, I had another idea that I would appreciate some advice on. To prevent or at least slown down HVAC contactor points burning and pitting, would it be feasable to hook up a 60 mfd 370 VAC capacitor so it would bridge the points. This would be the same as the old automobile ignition system that used points in the distributor with a capacitor wired in parallel to extend their life. This 60 mfd capacitor would be in addition to the existing motor run capacitor.
 
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