Motor SFRA, Partial Discharge, and Surge Tests

Use Inverter Technologies’ MOTORIT575 service with Surge Test and Partial Discharge measurement to diagnose low and medium voltage motor faults.

Motor stator winding insulation failure often starts as a turn-to-turn short, which eventually leads to catastrophic failure. Surge testing is the number one method used for detecting turn to-turn shorts and insulation faults within a winding.

Cracked or broken rotor bars results in motor failure due to loss of torque, extreme heat, and vibration. Rotor Influence Check is used to find cracked or broken rotor bars. Changes in air gap, between the rotor and stator, can cause excessive vibration and progress to bearing and winding failures.

Partial Discharge is a major contributor to the degradation of insulation systems. Adjustable Speed and Variable Frequency Drives produce high voltage spikes and overshoots, which causes partial discharge in stator windings. Partial Discharge will lead to eventual dielectric failure in the insulation.

A Class Above First!

Why Electric Motors Fail

• 50-60% Bearings • 15-35% Stator Windings • 16% External • 10% Unknown • 5% Rotor Bar • 2% Shaft Coupling

Although manufacturers label their motors as “inverter duty,” NEMA MG1 Part 31 is the mandated standard. Motors are tested to EASA or IEEE recommended voltages.

Stator Winding • Turn to Turn • Phase to Phase • Coil to Coil • Open • Short

Advanced Winding Loss Analysis

• A load measurement of impedance loss in a motor winding, reactor, or coil. • 1Hz to 1MHz Wide Bandwidth • At VFD Carrier Switching Frequency • Motor Drive Operating Frequency • Soft Starter 60Hz Line Frequency • Frequency Sweep from VLF (Very Low Frequency) 100uHz to 1MHz

MOTORIT575 Service

• Surge Test • Partial Discharge • Winding Resistance • Capacitance • Impedance • Inductance • Enviroment • Insulation Resistance • DC HiPot Test • Step Voltage • Ramp Voltage • PI • DAR • Dielectric Discharge • Rotor Influence Check • Time Domain Reflectometry • Equipotential Bonding • Infrared Thermography • Advanced Winding Loss Analysis

MOTORIT575 Advantages

Surge Test and IEC 61934 Standard Partial Discharge measurement provides the earliest detection of stator windings and insulation defects.
Effective for Carbon Tax Reduction and Climate Actions savings, by lowering energy consumption during motor and equipment service life.
Predictive Maintenance service improves Uptime Reliability, productivity, and earnings.

Others will guess what the problem is. Inverter Technologies will Find IT, Show IT, and Prove IT.

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Others will guess what the problem is. Inverter Technologies will Find IT, Show IT, and Prove IT.

Download PDF