Coil winding number variable type motor and coil winding number varying method for varying cooling and heating capacity of reciprocating compressor

A method for controlling a coil winding number variable type motor that is coupled to a reciprocating compressor, comprising:

• determining the winding number of a coil of the motor required for a desired stroke of the reciprocating compressor when a predetermined voltage is applied to the motor;
• decreasing a number of sub-coils connected to a main coil and applying a voltage to the main coil and sub-coils connected thereto by controlling a plurality of relays respectively connected between adjacent sub-coils and the main coil when a large stroke is required for the reciprocating compressor;
• and
• increasing the number of sub-coils connected to the main coil and applying a voltage to the main coil and sub-coils connected thereto by controlling a plurality of relays respectively connected between adjacent sub-coils and the main coil when a small stroke is required for the reciprocating compressor.

An electric appliance, comprising:

• a reciprocating compressor;
• a motor coupled to the compressor, wherein the motor includes a coil comprising a plurality of sub-windings configured to be selectively connected in series a plurality of relays respectively connected between adjacent sub-windings of the plurality of sub-windings;
• at least one sensor configured to sense at least one operating condition of the compressor and to output at least one corresponding signal;
• and
• a motor controller configured to receive the at least one signal, and to selectively switch the plurality of relays based on the at least one signal so as to vary the number of operative sub-windings of the coil.