how polarization index testing extends motor life
TRANSCRIPT
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Motor Polarization Index Testing How measuring insulation health can extend motor life.
What is a Polarization Index test?
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The Polarization Index (PI) test indicates motor insulation health. Polarization testing identifies accumulation of contaminants and physical changes in the insulation.
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Polarization Index Test Science
Polarization Index test applies a positive charge to motor conductors and a negative charge to motor frame. This polarizes insulation.
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Applying Motor Polarization Index Test
Electric Motor Repair Best Practices
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Healthy insulation records a smooth curve. Unhealthy insulation displays a flat curve.
Absorption of insulation contaminants over time reduces current and increases motor insulation resistance.
Motor Insulation Contaminants
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Diagram Courtesy of EC&M
Measuring Insulation Resistance
We use Baker AWA and PdMA Analyzers. The PdMA analyzer is used in the field to trend diagnostic data. The AWA carries the brunt of shop testing. PI testing should be part of a complete motor diagnostic testing program.
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Motor Repair Best Practices
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PI Test Shows Healthy Winding
Smooth Curve = Healthy Winding
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Courtesy of PdMA.
Erratic PI Test Shows Contamination
Electric Motor Contamination Increases Insulation Resistance
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Courtesy of PdMA.
Index Exceeds 5,000 IEEE Meg-Ohm Limit
PI Test Results Invalidated
Polarization Index Test Guidelines
2. A good PI Test shows smooth curve, leveling off after peaking.
1. Test in conjunction with other methods such as step voltage and acceptance testing.
Motor Polarization Index Testing guidelines simplify testing.
Healthy Insulation System
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The updated standard was outlined in the IEEE43 update. Changes include temperature and dew-point limitations, trending tests, surface conditions, windings.
IEEE43 Polarization Test Updated
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Polarization Index Test - Video
Motor Polarization Index Training Video
Download our motor testing and common standards guide. Ensure your motor shop observes these
standards.
For assistance with motor diagnostic programs, contact us at [email protected]
or call 800.993.3326
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