Patent ID: 7628028

Claim:
A method for modulating capacity in a compressor for an HVAC&R system, the method comprising: providing a compressor and a motor to power the compressor; measuring an outdoor ambient temperature; comparing the measured outdoor ambient temperature to a first predetermined temperature setpoint; operating the motor for the compressor at a first preselected output frequency and corresponding voltage in response to the measured outdoor ambient temperature being greater than the first predetermined temperature setpoint, wherein operation of the motor at the first preselected output frequency and corresponding voltage results in a first output capacity for the compressor; comparing the measured outdoor ambient temperature to a second predetermined temperature setpoint different from the first predetermined setpoint; operating the motor for the compressor at a second preselected output frequency and corresponding voltage in response to the measured outdoor ambient temperature being less than or equal to the second predetermined temperature setpoint, wherein operation of the motor at the second preselected output frequency and corresponding voltage results in a second output capacity for the compressor; and wherein a single speed fan is used with at least one of a condenser or an evaporator of an HVAC&R system.