Testing critical motors is vital for industry

When a motor is new the dielectric strength of the insulation is high but over time this slowly deteriorates and problems can emerge.

Operating environment and process variables can also adversely affect the motor's life.

Periodic motor monitoring will detect problems prior to likely failure, with all that implies for the process or operation.

Baker offers two testing types - offline and online.

The Offline Equipment
The offline equipment (AWA) is used to test the insulation system of the motor under bench test. These could be process motors, rail traction motors, wind generators, etc.

The test units provide a winding resistance test, a meg-ohm test, a PI test, a DC hipotential test (or ramp voltage test, or step voltage test), and a surge test.

The company says: “The surge test is the most important test offered, as it is able to detect weak insulation between turns, coils and phases prior to the motor displaying any symptoms of the fault. By surge testing once or twice a year, particularly on your critical motors, weak insulation can be detected and remedial work scheduled.

“The Megger is widely used for testing motors, but a Megger cannot detect weak insulation, turn to turn; only surge testing can detect intermittent shorting, made possible by weak insulation.”

The Online Equipment
The 'Explorer' online tester monitors the power being fed to the motor. It also looks at the performance of the motor itself as well as looking for rotor bar faults, efficiency problems and overloading problems, and finally, as the unit looks at the instantaneous torque of the motor, the unit can separate electrical and mechanical issues.

These test units allow large industrial complexes to ensure motor reliability, reduce downtime and detect inefficient motors, which are a major concern in these times of high-energy costs.

Baker testing systems for both on line (live) and off-line (bench) testing are in use worldwide and are represented in the UK and Ireland by Whitelegg.