Electric Power Utility Motor Case Study Diagnostics & Resolution Power utility contracted to perform...
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Electric Power Utility Motor Case Study Diagnostics & Resolution Power utility contracted to perform off-line circuit and insulation testing of critical motors during major planned outage. Tests included MCA, IR & overvoltage hipot and impulse. New 4 kV motors are impulse tested to 11.4 kVpk (IEEE). Recommended maintenance test is 9 kVpk. Impulse test discovered a 4 kV pump motor with phase insulation breakdown voltage of 7.2 kVpk. No indication of problem during MCA, IR and hipot tests. Utility opted to start the motor repeatedly to study failure of weak motor insulation system. Insulation failed catastrophically on fifth startup. Motor was rewound during planned shutdown Cost of Diagnostics to Utility: <$10,000 including travel Savings to Utility No lost production: Potentially $100Ks No emergency repair costs: $10Ks
Electric Power Utility Motor Case Study Diagnostics & Resolution Power utility contracted to perform off-line circuit and insulation testing of critical
Slide 2 Electric Power Utility Motor Case Study Diagnostics
& Resolution Power utility contracted to perform off-line
circuit and insulation testing of critical motors during major
planned outage. Tests included MCA, IR & overvoltage hipot and
impulse. New 4 kV motors are impulse tested to 11.4 kVpk (IEEE).
Recommended maintenance test is 9 kVpk. Impulse test discovered a 4
kV pump motor with phase insulation breakdown voltage of 7.2 kVpk.
No indication of problem during MCA, IR and hipot tests. Utility
opted to start the motor repeatedly to study failure of weak motor
insulation system. Insulation failed catastrophically on fifth
startup. Motor was rewound during planned shutdown Cost of
Diagnostics to Utility:
