Electrical Machines A DC motor with armature resistance of 0.5 ohms is connected directly to a 230 Volt supply. If the armature is stationary then the current flowing through armature is 460 A. 570 A. 340 A. 250 A. 460 A. 570 A. 340 A. 250 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an AC servomotor has one of its winding excited by AC, then voltage measured at the other winding with rotor running will be proportional to rotor speed. zero. proportional to square of rotor speed. constant independent of speed. proportional to rotor speed. zero. proportional to square of rotor speed. constant independent of speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC machine the armature mmf is rotating with respect to field poles. stationary with respect to armature. stationary with respect to field poles. rotating with respect to field poles as well as armature. rotating with respect to field poles. stationary with respect to armature. stationary with respect to field poles. rotating with respect to field poles as well as armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : Interpoles in dc machines 1. reducearmature reaction effects in the interpolar region 2. have the same dimension as main polls 3. have their windings connected in series with the armature 4. have same number of turns as the armature 5. have the polarity same as that of the main pole ahead in a motor From these, the correct statements are 1 and 3 1, 3 and 5 1, 2, 3 and 5 1, 2 and 3 1 and 3 1, 3 and 5 1, 2, 3 and 5 1, 2 and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 970 RPM 960 RPM 940 RPM 920 RPM 970 RPM 960 RPM 940 RPM 920 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor of a 3 - Φ wound induction motor is provided with three phase winding. heavy copper or aluminium bars placed in rotor slots. single phase winding. heavy short-circuited end rings. three phase winding. heavy copper or aluminium bars placed in rotor slots. single phase winding. heavy short-circuited end rings. ANSWER DOWNLOAD EXAMIANS APP
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