Electrical Machines A 240 V DC series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 ohms. The value of resistance which must be added to obtain rated torque at 1000 rpm is 1.9 ohms. 5.7 ohms. 6 ohms. 2.2 ohms. 1.9 ohms. 5.7 ohms. 6 ohms. 2.2 ohms. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For P pole machine relation between electrical degrees and mechanical degrees is θelec = 4/P*θmech θelec = P/2*θmech θelec = θmech θelec = 2/P*θmech θelec = 4/P*θmech θelec = P/2*θmech θelec = θmech θelec = 2/P*θmech ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is Pi/Pc (Pi/Pc)2 √(Pi/Pc) Pc/Pi Pi/Pc (Pi/Pc)2 √(Pi/Pc) Pc/Pi ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature mmf in a dc machine is 1. stationary with respect to field poles 2. stationary with respect to armature 3. rotating with respect to field poles 4. rotating with respect to armature From these, the correct answer is 2, 4 2, 3 1, 3 1, 4 2, 4 2, 3 1, 3 1, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Voltage across the open circuited field termninals of a synchorous machine under slip test is DC of slip frequency. A modulated supply frequency AC voltage with slip frequency envelop. AC of supply frequency. DC. DC of slip frequency. A modulated supply frequency AC voltage with slip frequency envelop. AC of supply frequency. DC. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a DC motor can be determined by Fleming's left hand rule. Ampere's law. Fleming's right hand rule. Lenz's law. Fleming's left hand rule. Ampere's law. Fleming's right hand rule. Lenz's law. ANSWER DOWNLOAD EXAMIANS APP
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