Electrical Machines The speed regulation of a DC motor is given as (NnL − NfL)/NfL. (NfL − NnL)/NnL. NnL/NfL. NnL − NfL. (NnL − NfL)/NfL. (NfL − NnL)/NnL. NnL/NfL. NnL − NfL. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole 50 Hz 1-phase induction motor is running at 1470 rpm. Find the forward and backward slips? 0.02, 1.98 0.04, 1.96 0.02, 0.98 0.04, 0.96 0.02, 1.98 0.04, 1.96 0.02, 0.98 0.04, 0.96 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1, 2, and 3 1, 2 and 4 2, 3 and 4 1 and 3 1, 2, and 3 1, 2 and 4 2, 3 and 4 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A compound dc generator is delivering full load current at a terminal voltage of 230 V. Its series-field winding gets short circuited. If its terminal voltage 1. becomes more than 230 V, it is overcompounded generator 2. becomes more than 230 V, it is differentially compounded generator 3. becomes less than 230 V, it is overcompounded generator 4. becomes less than 230 V, it is differentially compounded generator 5. becomes less than 230 V, it is level compounded generator From these, the correct answer is 1, 4 1, 4, 5 2, 3, 5 2,3 1, 4 1, 4, 5 2, 3, 5 2,3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of a motor falls from 1100 r.p.m at no-load to 1050 r.p.m at rated load. The speed regulation of motor is 2.57 %. 2.56 %. 3.76%. 4.76%. 2.57 %. 2.56 %. 3.76%. 4.76%. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The power factor of an induction motor operating at no load will have a value around 0.2 lag 0.9 lag 0.2 lead unity 0.2 lag 0.9 lag 0.2 lead unity ANSWER DOWNLOAD EXAMIANS APP
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