Re: [CAD_CAM_EDM_DRO] Re: VFD drive problems with older 3-phase motors (corre...

In a message dated 12/25/2003 5:52:03 PM Eastern Standard Time,
pete@... writes:
Ted, how was the motor originally connected to the contactors? How
could you possibly determine wye/delta from ohm-meter measurements
when wye and delta circuits are electrically equivalent?
Actually, the resistance measurements for wye connection would be approx.
double that of a delta connection within the motor. If the motor's internal
connection, or winding connection via and external terminal block, etc., is a
delta delta which is two delta configurations in parallel then the single wye
would be 4 times that of the delta delta.

Now, to figure out the correct "phasing" connections of the internal windings
is a bit more complicated and requires the use of a voltmeter and a 6 or 12
volt battery.

Randy Abernathy


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