Electrical Machines In a 3 - Φ IM with line frequency f1 and winding factor kw1 and kw2 for stator and rotor respectively the ratio of per phase stator winding emf E1 to per phase rotor winding emf E2 at standstill is given by E1 / E2 = N1 / N2. E1 / E2 = 1. E1 / E2 = N1kw1 / N2kw2. E1 / E2 = f1kw1 / f2kw2. E1 / E2 = N1 / N2. E1 / E2 = 1. E1 / E2 = N1kw1 / N2kw2. E1 / E2 = f1kw1 / f2kw2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An 8 pole DC generator has 500 armature conductors and useful flux per pole of 0.065 Wb. What will be the emf generated if it is lap connected and runs at 1000 rpm. What must be the speed at which it is driven to produce the same emf if it is wave wound? 541.67V, 200 rpm. 2166.67V, 270 rpm. 2166.67V, 230 rpm. 541.67V, 250 rpm. 541.67V, 200 rpm. 2166.67V, 270 rpm. 2166.67V, 230 rpm. 541.67V, 250 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In star-delta starting of squirrel cage induction motor compared to DOL starting the starting current and torque are 1/√3, 1/√3 1/3, 1/√3 1/3, 1/3 1/√3, 1/3 1/√3, 1/√3 1/3, 1/√3 1/3, 1/3 1/√3, 1/3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The use of double squirrel cage winding on the rotor provides a large starting torque. higher efficiency. reduced starting torque. low noise. a large starting torque. higher efficiency. reduced starting torque. low noise. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that Eb is zero, but Td is unchanged Eb is unchanged, but Td is zero both Eb and Td are zero both Eb and Td are unchanged Eb is zero, but Td is unchanged Eb is unchanged, but Td is zero both Eb and Td are zero both Eb and Td are unchanged ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What does the use the of height flux density value in transformer design lead to? Reduced iron loss. Decrease in weight/KVA. Increase in weight/KVA. Reduced copper loss. Reduced iron loss. Decrease in weight/KVA. Increase in weight/KVA. Reduced copper loss. ANSWER DOWNLOAD EXAMIANS APP
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