Electrical Machines If the load current and the flux of a DC motor are held constant and voltage applied across its armature is increased by 5%, the speed of the motor will remain unchanged. increase by 5 %. depend on other factors. reduce by 5 %. remain unchanged. increase by 5 %. depend on other factors. reduce by 5 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor has which of the following characteristics? Has a almost constant speed. Has its field winding consinting of thick wire and less no of turns. Can be started easily without load. Has a poor torque. Has a almost constant speed. Has its field winding consinting of thick wire and less no of turns. Can be started easily without load. Has a poor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque the flux waveform is improved with reduction in harmonics the inequality of air-gap flux on the top and bottom halves of the armature is removed a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque the flux waveform is improved with reduction in harmonics ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will increase by 100% reduced to half increase by 200% remain unaltered increase by 100% reduced to half increase by 200% remain unaltered 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 R2 = sX2. R2 = s2X2. R2 = s2X2. sR2 = X2. R2 = sX2. R2 = s2X2. R2 = s2X2. sR2 = X2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Diverters are used only in shunt motors series motors None of these either of these shunt motors series motors None of these either of these ANSWER DOWNLOAD EXAMIANS APP
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