It is said that we learn from our mistakes and in that light – I’m a genius! Motor testing, either energized or de-energized, should be a relatively straight forward process. If you’re not properly prepared it can be a frustrating experience. We all know that batteries, in particular, can be vindictive and mischievous intelligent life forms. It seems like batteries always wait until a crucial point, like 7-9.5 minutes into a polarization index, to fail! Spending a few minutes in preparation can stifle their efforts to impede your motor testing.
I have come up with a checklist that I go through to start my day before I am scheduled to perform motor testing:
- All batteries operable and charged (conditioned if applicable)
- Test leads are free of any nicks or cuts in the insulation
- Test lead clips are clean with no rust or corrosion, jaws intact
- Voltage clips are clean and free of any foreign debris
- Voltage clips are snuggly threaded or make a tight fit on test leads
- Current probes have good batteries (if applicable)
- Inspect power cords for nicks and breaks in the insulation
- Current probes jaws are clean and free of any foreign debris at both the top and hinge point
- Current probe spring tension is good
- Test lead connection points on the test instrument are clean and free of dust and foreign debris
- All electrical and data port cables on your test instrument are properly connected
In addition to the above check list it’s important that you know the following before you conduct testing:
- Distribution system type; Wye Delta, Delta Delta etc.
- System grounding; grounded, ungrounded etc.
- Power factor correction type, if applicable
- Full Nameplate data
- Full driven equipment data
- Driven component RPM mapping
Just a little time in preparation and compilation of applicable information can make motor testing a smooth process and analysis much easier.