Electrical Machines What is the necessity of copper brushes in a dc motors? To absorb the mechanical shocks produced during running condition. To convert alternating supply current to direct current. None of these. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. To convert alternating supply current to direct current. None of these. To increase the flux cutting by the rotor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The slip of an induction motor normally does not depend on which of the following? Core loss component. Rotor speed. Shaft torque. Synchronous speed. Core loss component. Rotor speed. Shaft torque. Synchronous speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Interpoles in a DC motor must be Series excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature. Series excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature. Shunt excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature. Shunt excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature. Series excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature. Series excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature. Shunt excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature. Shunt excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Due to magnetic saturation, the flux per pole in a DC machine without brush shift decreases in generators and increases in motor with load. increases in both the generators and the motors with load. decreases in both generators and the motors with load. increases in generators but decreases in motor with load. decreases in generators and increases in motor with load. increases in both the generators and the motors with load. decreases in both generators and the motors with load. increases in generators but decreases in motor with load. 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 = sX2. R2 = s2X2. sR2 = X2. R2 = s2X2. R2 = sX2. R2 = s2X2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC machine shape of main field flux distribution is? triangular flat tapped or trapezoidal saddle shape peaky in nature triangular flat tapped or trapezoidal saddle shape peaky in nature ANSWER DOWNLOAD EXAMIANS APP
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