Electrical Machines In a seperately excited DC Motor if field current is increased, it will Reduce armature heating. Increase acceleration duration. Reduce starting torque. Increase speed Reduce armature heating. Increase acceleration duration. Reduce starting torque. Increase speed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The following statements relate to compensating winding (CW) and interpole winding (IW) of a dc machine : 1. CW neutralizes the armature reaction under a pole pitch 2. IW is connected in series with armature circuit 3. IW produces mmf in the commutating zone only 4. CWmmf is directed along the brush axis 5. Mmf produced by IW is equal to armature mmf From these, the correct statements are 2, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 1, 3, 4, 5 2, 3, 4, 5 1, 2, 3, 4 and 5 2, 3, 4 1, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the speed control of dc motors : 1. ward-leonard method is suitable forconstant-torque drives 2. Ward-leonard method is suitable for constant-power drives 3. field-control method facilitates speed control below base speed 4. Armature-resistance control method is more efficient than ward-leanard method 5. Field-control method is suitable for constant-torque drives 6. Armature-resistance control method is suitable for constant-torque drives From these, the correct answer is 1, 2, 5 1, 4, 6 1, 3, 5 1, 2, 6 1, 2, 5 1, 4, 6 1, 3, 5 1, 2, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A synchronous machine has P number of poles, find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm)? ωe = P*ωm ωe = P/2*ωm ωe = ωm ωe = 2/P*ωm ωe = P*ωm ωe = P/2*ωm ωe = ωm ωe = 2/P*ωm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following load normally needs starting torque more than rated torque? Conveyers. Blowers. Air compressors. Centrifugal pumps. Conveyers. Blowers. Air compressors. Centrifugal pumps. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which motor cannot be started on no load? cumulative compound motors series motors both B and C shunt motors cumulative compound motors series motors both B and C shunt motors ANSWER DOWNLOAD EXAMIANS APP