Method and system for identifying performance degradation of a cooling subsystem in a locomotive

A system for determining degradation in cooling subsystem performance in a locomotive having an engine cooled by a fan powered by a motor, the system comprising:

• a signal monitor coupled to monitor a signal indicative of an electrical imbalance in at least one phase in the fan motor of the cooling subsystem;
• a first module coupled to the signal monitor to adjust the monitored signal for deviations from an estimated nominal phase signal value due to predetermined external variables to generate an adjusted phase signal value;
• and
• a second module coupled to the first module to receive the adjusted phase signal value, the second module configured to compare the value of the adjusted phase signal value against a nominal phase signal value to determine the performance of the cooling subsystem.