Electrical Machines In a synchronous motor when the rotor speed exceeds the synchronous speed during hunting negative sequence currents are generated. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. the damper bars develop induction motor torque. negative sequence currents are generated. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. the damper bars develop induction motor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The results of a slip test for determining direct axis (Xd) and quadrature axis (Xq) reactances of a star connected salient pole alternator are given below Phase values: Vmax = 108 V ; Vmin = 96 V Imax = 12 A ; Imin = 10 A Hence the two reactances will be Xd = 10.8Ω and Xq = 8Ω Xd = 9Ω and Xq = 9.6Ω Xd = 9.6Ω and Xq = 9Ω Xd = 8Ω and Xq = 10.8Ω Xd = 10.8Ω and Xq = 8Ω Xd = 9Ω and Xq = 9.6Ω Xd = 9.6Ω and Xq = 9Ω Xd = 8Ω and Xq = 10.8Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 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 efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 78.5% 72.5% 82.5% 67.5% 78.5% 72.5% 82.5% 67.5% 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? 0.04, 0.96 0.04, 1.96 0.02, 0.98 0.02, 1.98 0.04, 0.96 0.04, 1.96 0.02, 0.98 0.02, 1.98 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In synchronous motor, the damper winding is generally used to provide starting torque only. reduce the eddy currents. reduce noise level only. prevent hunting and provide the starting torque. provide starting torque only. reduce the eddy currents. reduce noise level only. prevent hunting and provide the starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For pure resistive load what is the armature reaction? cross magnetization demagnetization All of these magnetization cross magnetization demagnetization All of these magnetization ANSWER DOWNLOAD EXAMIANS APP
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