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Rotor Test
Rotor test is only performed on 3 Phase AC motor after stator is determined to be fault-free. For motors
with pole number 4 or less, 48 tests at minimum have to be performed on 48 different positions for one
cycle. In other words, one test has to be performed every 7.5
o
around 360
o
. For motors with pole
number of 6 or more, 72 tests have to be performed at minimum, i.e. one test every 5
o
.
To precisely determine every test position, an angle gauge can be attached to the rotor to determine to
rotation angle step. Or the users can find polar graph online and print it and attach it to the motor
frame with rotor shaft going through the center. An example is provided below.
Examples of polar graph: left- 5
o
interval, right – 7.5
o
interval.
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