US 9,810,218 B2
Crankcase heater systems and methods for variable speed compressors
Daniel L. McSweeney, Sidney, OH (US); Charles E. Green, Fenton, MO (US); and Stephen M. Seibel, Celina, OH (US)
Assigned to Emerson Climate Technologies, Sidney, OH (US)
Filed by Emerson Climate Technologies, Inc., Sidney, OH (US)
Filed on May 23, 2014, as Appl. No. 14/286,132.
Application 14/286,132 is a continuation of application No. 12/888,823, filed on Sep. 23, 2010, granted, now 8,734,125.
Claims priority of provisional application 61/245,394, filed on Sep. 24, 2009.
Prior Publication US 2014/0255209 A1, Sep. 11, 2014
This patent is subject to a terminal disclaimer.
Int. Cl. F25B 49/02 (2006.01); F04C 29/04 (2006.01); F04B 39/06 (2006.01); F04C 28/28 (2006.01); F04B 35/04 (2006.01); F04C 18/02 (2006.01)
CPC F04C 28/28 (2013.01) [F04B 35/04 (2013.01); F04C 29/045 (2013.01); F25B 49/022 (2013.01); F04B 39/06 (2013.01); F04C 18/0215 (2013.01); F04C 29/04 (2013.01); F04C 2240/81 (2013.01); F04C 2270/195 (2013.01); F04C 2270/701 (2013.01); F25B 2600/021 (2013.01)] 20 Claims
OG exemplary drawing
 
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.