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# A 6kW, 380V three phase induction motor of 0.96 power factor...

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 Question by Dhammika Submitted on 8/29/2003 Related FAQ: rec.woodworking Electric Motors Frequently asked Questions Rating: Rate this question: N/A Worst Weak OK Good Great A 6kW, 380V three phase induction motor of 0.96 power factor is udes to run a certain machine. It is observed that the motor takes 6 times the rated current at the instant of switching on and gradually drops to 96% of the rated current after 12 seconds when the machine is running at its normal steadly working speed. This motor is protected by means of a thermally operated over current relay and the circuit conductors feeding the motor are perotected by means of fuses conforming to BS 1361. FUSE    RATING  0.1sec  0.2sec  0.4sec  5sec5A       30A    25A     22A     14A15A      97A    80A     70A     40A20A      180A   155A    135A    82A30A      280A   240A    200A    125A45A      550A   470A    400A    240A60A      880A   720A    600A    330A80A      1100A  950A    800A    460A100A     1800A  1400A   1200A   630A a) calculate the rated current of the motorb) calculate the actual current drawen by the motor when running at steady speedc) what is the rating of the fuse (BS 1361) that you select for this circuit. justify your answer

 Answer by thevang Submitted on 2/16/2004 Rating: Rate this answer: N/A Worst Weak OK Good Great 1)The rated current of the motor is 16.45A. 2)The machine draws a current of15.8A when running at steady speed. 3)You have mentioned only about the overload so you can use 30A fuse as it can withstand 125A for 5sec as per BS 1361 standard.

 Answer by ramkumar Submitted on 7/14/2006 Rating: Not yet rated Rate this answer: N/A Worst Weak OK Good Great i want to know aboutthree phase induction motor

 Answer by odi the pogi Submitted on 11/30/2006 Rating: Not yet rated Rate this answer: N/A Worst Weak OK Good Great Current at full load will be 9.5A.  Then run at steady speed with a current of 9.12A.  Use a 15A fuse rating which can hold 70A current for 0.2sec.

 Answer by bcs Submitted on 4/3/2007 Rating: Not yet rated Rate this answer: N/A Worst Weak OK Good Great what does 3 phase mean

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