Hermetic electric compressor with improved temperature responsive motor control

A hermetic electric compressor comprising:

• a sealed casing;
• a motor unit provided in said sealed casing and having a stator coil;
• a compressor unit provided in said sealed casing and driven by said motor unit for compressing a refrigerant;
• a thermistor provided at said stator coil for monitoring a temperature of said stator coil;
• and
• control means, responsive to said temperature monitored by said temperature sensor, for controlling a speed of said motor unit via said stator coil,
• wherein said temperature sensor and said control means are connected via a twisted pair at least partly, and
• wherein said control means drops the speed of said motor unit to a preset value when the temperature monitored by said temperature sensor exceeds a first preset value and wherein said control means stops said motor unit when the temperature monitored by said temperature sensor exceeds a second preset value which is greater than said first preset value.

A hermetic electric compressor comprising:

• a sealed casing;
• a motor unit provided in said sealed casing and having a stator coil;
• a compressor unit provided in said sealed casing and driven by said motor unit for compressing a refrigerant;
• a thermistor provided at said stator coil for monitoring a temperature of said stator coil;
• control means, responsive to said temperature monitored by said thermistor, for controlling a speed of said motor unit via said stator coil, and
• wherein said control means drops the speed of said motor unit to a preset value when the temperature monitored by said thermistor exceeds a first preset value and wherein said control means stops said motor unit when the temperature monitored by said thermistor exceeds a second preset value which is greater than said first preset value.