Crankcase heater control

Abstract

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

Dependencies are inferred from the claim text.