Detection and correction of reverse operation of a compressor in a refrigeration system

A controller for a refrigeration system having an electric motor driven compressor, said refrigeration system comprising:

• means for monitoring refrigerant pressure at a suction side of said compressor;
• means responsive to monitored suction pressure being at least equal to a predetermined pressure at selected times after said motor driven compressor is turned on for turning off said motor driven compressor;
• and
• means for turning on said motor driven compressor a predetermined time after said means responsive turns off said compressor.

A refrigeration system having an electric motor driven scroll compressor operable in chilling and defrost cycles of said refrigeration system, said refrigeration system comprising:

• means for energizing said electric motor to turn on said compressor;
• means for monitoring refrigerant pressure at a suction side of said compressor;
• first timer means responsive to said compressor being turned on in a chilling cycle of said refrigeration system to initiate timing of a first time interval;
• first means for comparing monitored compressor suction side pressure to a predetermined pressure and for generating a first signal if said monitored pressure is at least equal to said predetermined pressure at the end of said first time interval;
• second timer means responsive to generation of said first signal to initiate timing of a second time interval;
• second means for comparing monitored compressor suction side pressure to the predetermined pressure and for generating a second signal if said monitored pressure is at least equal to said predetermined pressure at the end of said second time interval;
• means responsive to generation of said second signal for de-energizing said electric motor to turn off said compressor;
• third timer means responsive to generation of said second signal for initiating timing of a third time interval;
• and
• means for re-energizing said electric motor at the end of said third time interval to turn on said compressor in a chilling cycle of said refrigeration system.

A method of controlling a refrigeration system having an electric motor driven scroll compressor, said method comprising the steps of:

• energizing the electric motor to operate the compressor;
• monitoring refrigerant pressure at a suction side of the compressor;
• determining whether monitored refrigerant pressure is at least equal to a predetermined pressure both after expiration of a first time interval following energization of the motor and after expiration of a second time interval following expiration of the first time interval;
• de-energizing the motor to turn off the compressor for a third time interval in response to said determining step determining that monitored compressor suction side pressure is at least equal to the predetermined pressure after expiration of each of the first and second time intervals;
• and
• re-energizing the electric motor to operate the compressor following expiration of the third time interval.

A method of controlling a refrigeration system having an electric motor driven compressor, said method comprising the steps of:

• sensing whether the compressor is on;
• determining whether compressor suction side pressure is at least equal to a predetermined pressure at the end of a first time interval following said sensing step sensing that the compressor is on;
• ascertaining, in response to said determining step determining that compressor suction side pressure is at least equal to the predetermined pressure at the end of the first time interval, whether compressor suction side pressure is at least equal to the predetermined pressure at the end of a second time interval following the first time interval;
• turning off the motor driven compressor for a third time interval in response to said ascertaining step ascertaining that compressor suction side pressure is at least equal to the predetermined pressure at the end of the second time interval;
• and
• turning on the motor driven compressor at the end of the third time interval.

A method of controlling a refrigeration system having an electric motor driven scroll compressor operable in chilling and defrost cycles of the refrigeration system, said method comprising the steps of:

• energizing the electric motor to turn on the compressor;
• monitoring refrigerant pressure at a suction side of the compressor;
• sensing whether the compressor is on in a defrost cycle of the refrigeration system;
• initiating timing of a first time interval in response to said sensing step sensing that the compressor is on and not in a defrost cycle of the refrigeration system;
• determining, after expiration of the first time interval, whether monitored pressure at the suction side of the compressor is at least equal to a predetermined pressure;
• initiating timing of a second time interval in response to said determining step determining that monitored compressor suction side pressure is at least equal to the predetermined pressure after expiration of the first time interval;
• ascertaining, after expiration of the second time interval, whether monitored compressor suction side pressure is at least equal to the predetermined pressure;
• turning off the compressor in response to said ascertaining step ascertaining that monitored compressor suction side pressure is at least equal to the predetermined pressure after expiration of the second time interval;
• initiating timing of a third time interval in response to performance of said turning off step;
• and
• re-energizing the electric motor to turn on the compressor in a chilling cycle of the refrigeration system after expiration of the third time interval.