Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 1 at 90°C. 3 at 90°C. 0.5 at 90°C. 2 at 90°C. 1 at 90°C. 3 at 90°C. 0.5 at 90°C. 2 at 90°C. 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 = 8Ω and Xq = 10.8Ω Xd = 9.6Ω and Xq = 9Ω Xd = 10.8Ω and Xq = 8Ω Xd = 9Ω and Xq = 9.6Ω Xd = 8Ω and Xq = 10.8Ω Xd = 9.6Ω and Xq = 9Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two of supply terminals to a 3 - Φ induction motor get interchanged during re-connection after normal maintenance. When switched on the supply, the motor will rotate in direction opposite to that before maintenance. not start at all. rotate in the same direction as before maintenance. get heated and damaged. rotate in direction opposite to that before maintenance. not start at all. rotate in the same direction as before maintenance. get heated and damaged. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following DC Motor uses 4-point starter? DC compound motor. DC series motor. DC shunt motor with armature resistance. DC shunt motor with field weaking control. DC compound motor. DC series motor. DC shunt motor with armature resistance. DC shunt motor with field weaking control. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor is running with a divertor connected across its field winding. If the divertor resistance is reduced then the speed of the motor will increase. become execessively high. remain unaltered. decrease. increase. become execessively high. remain unaltered. decrease. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole wave wound dc motor having flux per pole of 9.56 X 10-3 Wb contains 460 armature conductors with armature resistance of 0.6 ohm. Calculate the starting current flowing through the armature if the supply voltage is 240 volt. 400 Amp. 800 Amp. 0.5 Amp. 320 Amp. 400 Amp. 800 Amp. 0.5 Amp. 320 Amp. ANSWER DOWNLOAD EXAMIANS APP
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