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US 9,810,218 B2Granted
Crankcase heater systems and methods for variable speed compressors
AssigneeEmerson Climate Technologies, Inc.
InventorsDaniel L. McSweeney, Charles E. Green, Stephen M. Seibel
Life of this patent
Estimating the term…
Abstract
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.
Claims20
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.
2 more elements
A method comprising:
- controlling, with a control module connected to a variable frequency drive, a speed of an electric motor that drives a compression mechanism of a compressor by varying, with the variable frequency drive, a frequency of a voltage delivered to the electric motor in an on state;
- controlling, with the control module, electric current supplied to a stator of the electric motor by the variable frequency drive to heat the stator of the electric motor in an off state, the compression mechanism not being driven by the electric motor in the off state;
- receiving, with the control module, a compressor temperature signal generated by a compressor temperature sensor and corresponding to a compressor temperature;
- determining, with the control module, a desired compressor temperature;
- comparing, with the control module, the compressor temperature with the desired compressor temperature;
- and
- determining, with the control module, an amount of electric current to supply to the stator in the off state based on the comparison.
4 more elements
Dependencies are inferred from the claim text.