3 phase induction motor core loss calculations

Thread Starter

Ande

Joined Feb 3, 2017
39
I have worked out what I think is the solution to a 3 phase induction motor problem but the stator core loss value obtained seems too high to be right. Please help. Question 3 is the one I need help with, the other questions have been given for background purposes. My attempts are attached.

A 3 phase 6 pole induction motor has a star connected stator with impedance (0.5+j2.5) while the rotor standstill impedance is (0.1 + j 0.6). The shunt impedance is 12+j61. If the supply voltage is 630V and the effective turns ratio is 2:1, calculate the ff at 965 rpm

1. Rotor impedance referred to the stator
2. Stator current and pf
3. Stator copper and iron loss
 

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drc_567

Joined Dec 29, 2008
751
You might review the calculation of Z0. That value carries through and might affect the final answer, as I understand your notation.
 

Thread Starter

Ande

Joined Feb 3, 2017
39
You might review the calculation of Z0. That value carries through and might affect the final answer, as I understand your notation.
As far as I know, Z0 represents the no load loss (hence the parallel branch) which is why I've calculated it the way I did. Kindly provide some insight as to what I need to review. Thanks
 

Thread Starter

Ande

Joined Feb 3, 2017
39
The calculation of R0||jX0 is incorrect, in particular the angle is only 2.3 degrees, not 11.1 degrees.
Since this is a parallel network, the impedance can be calculated as: Ro(jXo)÷(Ro + jXo). That's what I've done and I keep getting the same answer quoted above. Is my technique incorrect?
 

drc_567

Joined Dec 29, 2008
751
The numerical calculations shown appear to be numerically correct. The only question is in 3.3, where the radial magnitudes of V and I are used to calculate the corresponding power losses, rather than using the real part of those vectors.
 
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