Stator Core Phase Rotation
Stator Core Phase Rotation
(OP)
Can I test a stator core for proper phase rotation prior to varnish treatment? I know I can power it up and use the spinning can trick but I am hoping there is something we can do at our test stand without high volts or amps. Any comments are much appreciated. Thank you.





RE: Stator Core Phase Rotation
For small machines, use standard rotation meter. For larger machines, an oscilloscope can be used as described in my attachment 12 Mar 12 8:11 in the following thread:
thread237-318005: Detaermining the Rotation Direction of generators
(there may be other stuff in the thread of interest since the subject was basically the same as yours... no difference in determining rotation direction for motor or generator)
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(2B)+(2B)' ?
RE: Stator Core Phase Rotation
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(2B)+(2B)' ?
RE: Stator Core Phase Rotation
RE: Stator Core Phase Rotation
RE: Stator Core Phase Rotation
This test will be performed on an assembly line and the rotor is not present. It is a green wound stator core and I prefer not to introduce high voltage due to safety concerns.
Thanks for you help. mbailey.
RE: Stator Core Phase Rotation
Is this a good approach or should I be going in a different direction? Again, thanks for your help.
RE: Stator Core Phase Rotation
IMO to test if one winding is correct connected(Stator) is connecting all leads(In star or delta)and applying DC low Voltage to the leads 1,2,3.(Use a DC welding machine) then use a compass in order to detect how many south and north poles are. You most see the same north and south poles qty.
Note: The total poles can be calculated from the Motor Synch Speed.
60 Hz: 3600 RPM (2 POLES)-1800 RPM(4 POLES)-1200 rpm(6 POLES)-900 RPM(8 POLES)
50 Hz: 3000 RPM (2 POLES)-1500 RPM(4 POLES)-1000 rpm(6 POLES)-750 RPM(8 POLES)
For other speed apply : RPM Synch = 120*F/P where F is the frequency and P the poles number.
Example: 60 Hz motor with name plate Speed of 1750 RPM this is a Sych speed of 1800 RPM = 4 poles.
Another way is applying three phase voltage to the stator complete connected and if the winding is good connected the Amps per phase most be equal, if you have significative difference then you have a problem, this method require a very large power system due to the currents are high, specialty on medium and large size motors.
Regards
Carlos