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 1, 4 2, 3 1, 3 2, 4 1, 4 2, 3 1, 3 2, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case the conditions for maximum power for DC motor are established, the efficiency of the motor will be Less than 50 % Any where between 75 % and 90 %. Around 100 %. Around 90 % Less than 50 % Any where between 75 % and 90 %. Around 100 %. Around 90 % ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The noise resulting from vibrations of lamination set by magnetic forces, is termed as hum. magnetostriction. boo. zoom. hum. magnetostriction. boo. zoom. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Belt conveyors offer _______________ starting torque. high. medium. zero. low. high. medium. zero. low. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A cumulatively compounded dc motor delivers rated load power at rated speed. If the series field is short-circuited, then Ia remains constant but ωm increase both armature current Ia and speed ωm increase both decrese Ia increases and ωm decreses Ia remains constant but ωm increase both armature current Ia and speed ωm increase both decrese Ia increases and ωm decreses ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ? 2 alone 1 and 2 1, 2 and 3 1 and 3 2 alone 1 and 2 1, 2 and 3 1 and 3 ANSWER DOWNLOAD EXAMIANS APP
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