For almost a year now, the electro-mechanical circuit that many folks helped me design has been working perfectly (reference: Seeking Basic Non-Electronic Gate Opener Circuit.) A problem arose for the first time today. When the gate didn't work I found the motor running with the belt slipping. It was quite hot but had not yet tripped the thermal overload switch. Upon diagnosis, I found that one of the SPDT relays, the one that controls the motor rotation direction, had failed. I was surprised because I had chosen very robust ratings- 20a relay rating- for the gate opener motor, which draws 5a! This was replaced and all seemed well until the 1/2 hp motor wouldn't start. This motor has a capacitor with 4 terminals: there is line voltage across two of the terminals, with the other two connected to the aforementioned relay to reverse the rotation. The motor would sit and buzz, but manually spinning the motor shaft to give the motor a start would cause the motor to run properly in either direction, and otherwise the gate would work properly. While I would think the capacitor would be highly suspect there is a complication. Under load the voltage to the motor drops from 115 to 109 volts. There has been an intermittent problem, both at the breaker box and the pole, supposedly caused by salt corrosion. (The gate is near the ocean.) Although the motor is rated at 120V, my understanding is that +/- 10% is permissible. This would mean that 109V was OK, but before calling the electric company I wanted your opinion. So I'm thinking there are 3 potential issues causing the motor not starting by itself: bad capacitor, low line voltage, and possible damage to the motor caused by overheating earlier (even though the overload didn't trip.) Please help me sort this out. Anything else you can think of? Can anything be ruled out?
Many thanks for your help last year, and now.
Frank
Many thanks for your help last year, and now.
Frank