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Testing a 100HP Vertical Motor

relic626

Electrical
Jun 15, 2025
1
Good day all, I'm in need of assistance in understanding a method of testing on a 100HP Motor.
The motor underwent Repairs and I need to perform final Testing.
However it is meant to Run at 230V Delta and as it stands my Testing Station does not meet the Requirements to Run the Motor Due to Amperage Limitations.
I was advised by a Local Technician that I can Connect the Motor in Star & Run at 230V in Order to Test the Motor.
I have Done this and the Motor was able to Start and Run without Issue.

I'm getting 16Amps on Each of the 3 Phases No Load (Running at 230V and Connected in Star).
Is there any way to Correlate the 16amps reading to a Nominal Value if it were to be Tested at the Proper 230V Delta Connection?

See Nameplate Information in the attachment.


Thanking you all in advance.
 

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Is there any way to Correlate the 16amps reading to a Nominal Value if it were to be Tested at the Proper 230V Delta Connection?
Without a load test, any correlation may be meaningless.
But, on a wye connection at 230 Volts, each winding will see 133 Volts.
By Ohm's law you may expect 28 Amps at 230 Volts delta.
Or not.
Why not a wye/delta start?
 
No load run at reduced (aka star connected delta winding) is fine as long as you didn't rewind the motor. You check if the vibrations and stabilized bearings temperatures at rated speed are within limits.
If you did rewind the motor, the client may require a rated voltage test which will require rated no-load current supply capacity, which is normally 30 to 40% of rated load current.
Delta current will not be linear from star current due to magnetic saturation at delta connection.
 

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