CRANKCASE HEATER SYSTEMS AND METHODS FOR VARIABLE SPEED COMPRESSORS

摘要

A system includes a compressor having a shell housing a compression mechanism driven by an electric motor in an on state and not driven by the electric motor in an off state. The system also includes a variable frequency drive that drives the electric motor in the on state by varying a frequency of a voltage delivered to the electric motor and that supplies electric current to a stator of the electric motor in the off state to heat the compressor.

主权项

1. A system comprising:
a compressor including a compression mechanism driven by an electric motor in an on state and not driven by the electric motor in an off state; a variable frequency drive that drives the electric motor in the on state by varying a frequency of a voltage delivered to the electric motor and that supplies electric current to a stator of the electric motor in the off state to heat the compressor; a compressor temperature sensor that generates a compressor temperature signal corresponding to a compressor temperature; a control module connected to the variable frequency drive that controls a speed of the electric motor in the on state and that controls the electric current supplied to the stator of the electric motor in the off state; wherein the control module receives the compressor temperature signal, determines a desired compressor temperature, compares the compressor temperature with the desired compressor temperature, and determines an amount of electric current to supply to the stator in the off state based on the comparison.