Electrical Machines A DC Shunt Motor having shunt field resistance of 250 Ω and armature resistance of 0.5 Ω is connected to 250 V supply and load current of 21 A. What is the back emf generated ? 240 V. 150 V. 230 V. 210 V 240 V. 150 V. 230 V. 210 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the frequency of a alternator, if P = number of poles and N = revolution made per second? 120 / PN Hz. PN / 2 Hz. 120N / P Hz. 120P / N Hz. 120 / PN Hz. PN / 2 Hz. 120N / P Hz. 120P / N Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The reduced air gap results in an increase power factor. cost of operation. starting torque. breaking torque. power factor. cost of operation. starting torque. breaking torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the source voltage of a DC motor is increased, which of the following will decrease? Full load current. Operating speed. Starting torque. Starting torque, operating speed, full load current. Full load current. Operating speed. Starting torque. Starting torque, operating speed, full load current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Stray losses in transformer occurs in steel core. paper insulation in transformers. transformer insulating oil. winding conductors and steel structures of transformer. steel core. paper insulation in transformers. transformer insulating oil. winding conductors and steel structures of transformer. ANSWER DOWNLOAD EXAMIANS APP
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