Question
Download Solution PDFA 3-phase induction motor draws 50 kW from a 220 V, 50 Hz mains. The rotor emf makes 100 oscillations/minute. If the stator losses are 2 kW the rotor copper loss would be
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
Power flow in the Induction motor is as shown below.
Rotor input or air gap power
Rotor copper losses
Gross mechanical power output
The relation between the rotor air gap power, rotor copper losses and gross mechanical power output is,
Calculation:
Frequency of rotor emf (fr) = 100 oscillations/minute
= 100/60 oscillations/second
= 1.66 Hz
Supply frequency (f) = 50 Hz
Slip (s) = fr/f = 1.66/50 = 0.033
Motor input = 50 kW
Stator losses = 2 kW
Rotor input = stator output = 50 – 2 = 48 kW
Rotor copper losses = 0.033 × 48 = 1.6 kW
Last updated on May 28, 2025
-> UPSC ESE admit card 2025 for the prelims exam has been released.
-> The UPSC IES Prelims 2025 will be held on 8th June 2025.
-> The selection process includes a Prelims and a Mains Examination, followed by a Personality Test/Interview.
-> Candidates should attempt the UPSC IES mock tests to increase their efficiency. The UPSC IES previous year papers can be downloaded here.