How do you calculate the resistance of a 3 phase motor?
R in ohms = Rated voltage /(rated current x1. 732×3. 5). Example : 2000kw motor, rated voltage is 6600v, rated current is 175A, then R= 6600/(175*1.732*3.5) = 6.22.
How do you calculate motor winding resistance?
Ohm’s law tells you that current through a wire – even a long wire wound around a motor solenoid – is equal to the voltage divided by the resistance. You can determine the resistance of a motor coil if you know the wire gauge, the radius of the solenoid and the number of windings.
How many ohms should a 3 phase motor read?
The windings (all three in a three-phase motor) should read low but not zero ohms. The smaller the motor, the higher this reading will be, but it should not be open. It will usually be low enough (under 30 Ω) for the audible continuity indicator to sound.
What is a good megohm reading for a motor?
Anything reading between 2 megohms and 1000 megohms is usually considered a good reading, unless other problems have been noted. Anything less than 2 megohms indicates an insulation problem.
How many ohms should a motor read?
With a multimeter, measure the resistance between motor frame (body) and earth. A good motor should read less than 0.5 ohms. Any value greater 0.5 ohms indicate trouble with the motor.