Discussion
A 4-pole, 3-phase induction motor is running at a speed of 1380 rpm. If the supply frequency is 50 Hz, find the slip.
Answer: A
The synchronous speed of a 4 pole motor on a 50 Hz supply is
\[ \begin{aligned} N_s = \frac{120f}{P} = \frac{120 \times 50}{4} \\ &= 1500\ \text{rpm} \end{aligned} \]
\[ \begin{aligned} s = \frac{N_s - N}{N_s} \\ &= \frac{1500 - 1380}{1500} = \frac{120}{1500} \\ &= 0.08 = 8\% \end{aligned} \]
The values 6%, 4% and 2% would need speeds of 1410, 1440 and 1470 rpm. The answer is 8%, option A.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development