6T7L71CPE
New member
I've got a Leeson Permanent Split Capacitor reversible motor from an electric gate that was blowing a circuit board fuse. It was in the vicinity of a lightning strike that blew out neighbors cable boxes, PC's etc.
I pulled the motor to bench test it, hooked the line to T1 and T3 and it started up say CW. I hooked up the line to T2 and T3 and it just hummed. I gave the motor a CCW twist then plugged it and it ran. I figured I found my problem.
It's got dual 50uf caps so I (incorrectly) assumed one was for each direction. I swapped the caps over and the CCW T2/T3 now started fine, curiously, so did the CW T1/T3 connection. I switched the caps back to the original positions and the motor works fine both ways still.
I then contacted Leeson and they sent the attached schematic. And after some reading on PSC motors I now know the caps are in parallel as run caps and not set up as CW and CCW start caps. Supposedly both caps need to be bad to keep it from starting. I tested both caps, which look physically good, no leaks, bulges, and they are reading 50uf.
I have not put the motor back in the gate yet, I plan to replace the caps for good measure.
Now, I'm grateful it's working, but, I want to understand why it just hummed initially when hooked up to T2 and T3. The ONLY thing I can think of is one of the cap connectors had a bad connection from the lighting strike and moving them cleaned the connection. Any motor guru's out there have an idea?
I pulled the motor to bench test it, hooked the line to T1 and T3 and it started up say CW. I hooked up the line to T2 and T3 and it just hummed. I gave the motor a CCW twist then plugged it and it ran. I figured I found my problem.
It's got dual 50uf caps so I (incorrectly) assumed one was for each direction. I swapped the caps over and the CCW T2/T3 now started fine, curiously, so did the CW T1/T3 connection. I switched the caps back to the original positions and the motor works fine both ways still.
I then contacted Leeson and they sent the attached schematic. And after some reading on PSC motors I now know the caps are in parallel as run caps and not set up as CW and CCW start caps. Supposedly both caps need to be bad to keep it from starting. I tested both caps, which look physically good, no leaks, bulges, and they are reading 50uf.
I have not put the motor back in the gate yet, I plan to replace the caps for good measure.
Now, I'm grateful it's working, but, I want to understand why it just hummed initially when hooked up to T2 and T3. The ONLY thing I can think of is one of the cap connectors had a bad connection from the lighting strike and moving them cleaned the connection. Any motor guru's out there have an idea?