motor nameplate information #3 – Performance

Last time i already discuss about Electrical input and Mechanical output parameters.This time i try to describe about performance parameter.Normally this parameter tell about motor efficiency,services factor and motor duty.From this parameter we can decide and design the system for efficiency motor.

We can determine the suitable stater such as inverter,VSD or soft stater to control the motor running operation.If motor can running in high efficiency,we can save a maintenance cost,electrical cost and improve productivity.

Here i explain detail about performance parameter that normally state on electric motor name plate :-


Motor Performance

  • NEMA Nom. Efficiency

Efficiency is defined as output power divided by input power expressed as a percentage:
(Output -, Input) x 100

NEMA nominal efficiency on a nameplate represents an average efficiency of a large population of like motors

  • Service factor

The service factor (S.F.) is required on a nameplate only if it is higher than 1.0. Industry standard service factor includes 1.15 for open-type motors and 1.0 for totally enclosed-type motors. However, service factors of 1.25, 1.4, and higher exist.

  • Duty

It defines the length of time during which the motor can carry its nameplate rating safely. Most often, this is continuous (“Cont”). Some applications have only intermittent use and do not need motor full load continuously.

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