Electrical Machines Maximum allowable tan - delta (tanδ) of dielectric dispassion factor of power transformer insulating oil is generally taken as 0.5 at 90°C. 1 at 90°C. 3 at 90°C. 2 at 90°C. 0.5 at 90°C. 1 at 90°C. 3 at 90°C. 2 at 90°C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A three phase induction motor has a synchronous speed of 1500 rpm the machine runs at 1460 rpm at a particular load. The slip at this load is ___________. 1.5 %. 30 %. 5 %. 2.67 %. 1.5 %. 30 %. 5 %. 2.67 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC series motor operating at rated speed, the speed of the motor will Increase. Reduce. Oscillate around the normal speed. Remain unaltered. Increase. Reduce. Oscillate around the normal speed. Remain unaltered. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For power factor improvement the synchronous motor is to be lightly loaded and over excited lightly loaded and underecited heavily loaded and over excited heavily loaded and underexcited lightly loaded and over excited lightly loaded and underecited heavily loaded and over excited heavily loaded and underexcited ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is/are the necessary conditions for parallel operation of alternators? Speed of alternators should be same Frequency should be same Terminal voltage is same Both 1and 2 Speed of alternators should be same Frequency should be same Terminal voltage is same Both 1and 2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When R2 is rotor resistance, X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condition will be sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. ANSWER DOWNLOAD EXAMIANS APP
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