Troubleshooting help with a single-phase 5Hp motor/compressor
Good evening and Happy New Year to all.
I am trying to find the cause for the overheating of a 5 HP single phase motor which turns a belt driven refrigeration compressor. The FLA at the plate reads 21.5 amps, while the running amps in my meter never read above 21.0 amps.
The motor does not run continuously: it has a thermostat controlled pumpdown type control system, cycled by the low pressure control. Nevertheless, as the motor runs for a few hours, it becomes hotter and hotter until the thermal protector opens. I already replaced both the start and run capacitors. One thing I did notice is that this is a 230 volts motor, not the regular 208/230 volts, but the line voltage stays between 208 and 210 volts. It had been working without trouble for 5 years. Never re-wound before. What do you thing?