Practical approach for determining motor efficiency in the field using calculated and measured values

There are many "black boxes" offered to advise the efficiency of installed motors. The major problem with most of those devices is that access to the motor is required; motors must be taken out of service to add instrumentation resulting in excess costs and time. This approach is to take readings at the motor control center or motor starter, without having to disturb the motor or having to take an outage. The results obtained are more than adequate to study and estimate energy savings possibilities.