Monitoring of Electric Motors

Every industrial plant has critical electric motors that should be monitored to stay alert to potential problems that could interrupt production.

Failure Modes

Vibrations in electrical machines can have a mechanical or electrical cause. The symptoms used to diagnose electrical faults can be found in the vibration spectra or in the dynamic current or voltage signal of the motor in each phase. Electrical problems detectable using vibration, current, and voltage analysis techniques can be classified into six failure modes:

• Power quality issues, detectable via a power test.
• Faults in the power circuit, detectable through standard tests and the power test.
• Insulation defects, detectable by the standard test, the polarization index, and the step-voltage test.
• Stator faults, detectable by the standard test, rotor influence, the power test, and the start-up test.
• Rotor failures, detectable through vibration analysis, standard testing, rotor influence testing, rotor evaluation, and start-up testing.
• Air gap defects, detectable by vibration analysis, standard test, rotor influence, and eccentricity test.

More technical information here.

Monitoring Systems

The recommended monitoring systems for electric motors are:
Offline measurement equipment: Monitoring of failure-mode parameters using periodic vibration surveys with portable equipment.
Online Monitoring Systems: Continuous monitoring and diagnosis of vibration, voltage, and current.

Related links:

• Electric Motor Diagnostic Services.
• Course on Predictive Maintenance of Electric Motors.
• Return on Investment Analysis.

Please contact our sales department at info@preditec.com to request a proposal for monitoring your machinery.