Electrical Machines The fall in speed of the DC generator due to increase in load can be corrected by cooling the armature. increasing the input to the prime mover. increasing the excitation. reducing the load voltage. cooling the armature. increasing the input to the prime mover. increasing the excitation. reducing the load voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A Shunt generator running at 1000 rpm has generated emf of 100 V. If the speed increases to 1200 rpm, the generated emf will be nearly 140 V 240 V 120 V 175 V 140 V 240 V 120 V 175 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 1, 3, 5 1, 2, 3, 4 1, 2, 5 2, 3, 4 1, 3, 5 1, 2, 3, 4 1, 2, 5 2, 3, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The demagnetising component of armature reaction in a DC generator reduces inter poles flux density. results in sparking trouble. increases armature speed. reduces generator emf. reduces inter poles flux density. results in sparking trouble. increases armature speed. reduces generator emf. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a DC Shunt Motor having armature resistance of 0.5 Ω and 2 A armature current at no-load, when the armature current is changed to 20 A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load? 4575.4 r.p.m. 1130 r.p.m. 1037.5 r.p.m. none of above. 4575.4 r.p.m. 1130 r.p.m. 1037.5 r.p.m. none of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, the space distribution of air-gap flux density wave at no load is sinusoidal co- sinusoidal flat-topped rectangular sinusoidal co- sinusoidal flat-topped rectangular ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS