Compressor heater control

摘要

A controller for controlling a heater 10 associated with the crankcase 12 of a compressor senses electrical current flowing through the heater 10. The sensing is preferably accomplished by a transformer 22 in combination with an amplifier 24 providing a feedback signal to the controller. The transformer 22 is installed in the line which carries the electrical current flowing through the heater 10. The controller checks for the presence of an appropriate voltage level from the amplifier 24. In the event that the voltage level is not above a threshold level, the controller sends an alarm signal indicating that the heater 10 is not operating properly. <IMAGE>