Electrom Instruments said one of the key points of failure in an electric motor, after bearings, is the insulation system. When insulation weaknesses develop due to harsh work-site conditions, windings eventually begin to leak current to the ground, one winding to another, or from a turn in the winding to the next turn.
The result is less efficiency, greater heat build-up, more rapid breakdown of the insulation and ultimately the failure of the motor. By performing tests using a portable analyzer and diagnosing any issues early, maintenance personnel can minimize repairs and avoid extensive downtime.
The latest electric motor analysis devices are capable of measuring and analyzing a variety of key performance indicators, and Electrom noted that one of the advantages of today’s most advanced instruments is that many are both easy to operate and offer powerful features. The company’s iTIG II, for example, is a winding analyzer and motor tester that comes with numerous options and output ranges from 4 kV to 12 kV. By adding Power Packs, even higher voltages are possible. All iTIG models use a 60-Hz surge pulse frequency, the same frequency at which most motors operate. This high pulse rate overcomes ionization dissipation and can isolate insulation weaknesses with more sensitivity, predicting faults faster than low frequency testers, and it can also better simulate motor operating conditions.
According to the company, its winding analyzers allow users to enter the surge test voltage, push a button, and let the machine run the test independently. Surge waveform ranges are automatically set for all models, which eliminates the need to specify configurations, push multiple buttons, or turn dials. Test routines include Surge Comparison, DC Hipot, Step Voltage, Insulation Resistance (Meg test), Dielectric Absorption (DAR), Polarization Index (PI), Low resistance (Ohms), Impedance (Z), Phase Angle, Inductance (L), and Capacitance (C).
Additionally, motor and customer information can be set up on a PC and transferred to the iTIG II before tests are done. This eliminates the need for the operator to enter any information in the analyzer. The motor can just be selected and testing started. Most motor and customer information can be entered before or after a test.
