Electrical Machines The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is 50 Hz. 60 Hz. 25 Hz. 16.67 Hz. 50 Hz. 60 Hz. 25 Hz. 16.67 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a DC motor can be determined by Fleming's left hand rule. Fleming's right hand rule. Ampere's law. Lenz's law. Fleming's left hand rule. Fleming's right hand rule. Ampere's law. Lenz's law. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Capacitor start capacitor run provides high staring torque only. high staring torque and high power factor. none. high power factor only. high staring torque only. high staring torque and high power factor. none. high power factor only. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The counter (or back) emf in a dc machine is 1. the same as generated emf in a dc motor 2. proportional to field flux and armature speed 3. not the same as generated emf in a dc motor 4.inversely proportional to field flux 5. proportional to number of armature conductors 6. constant from no load to full load From these, the correct answer is 1, 2, 5 3, 4, 5 2, 4, 5, 6 2, 3, 6 1, 2, 5 3, 4, 5 2, 4, 5, 6 2, 3, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In 3 - Φ induction motor some times copper bars are placed deep in the rotor to reduce copper loss. improve efficiency. improve power factor. improve starting torque. reduce copper loss. improve efficiency. improve power factor. improve starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following speed control of DC motor the speed obtained is below than the rated speed? Armature circuit resistance control. Any of above. Armature voltage control. Field resistance control. Armature circuit resistance control. Any of above. Armature voltage control. Field resistance control. ANSWER DOWNLOAD EXAMIANS APP
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