DC Motors Excessive sparking at brushes may be caused due to Misaligment of machine Loose coupling Worn bearings Dirt on the commutator Misaligment of machine Loose coupling Worn bearings Dirt on the commutator ANSWER DOWNLOAD EXAMIANS APP
DC Motors If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens Nothing will happen to motor This will make armature to take heavy current, possibly burning it This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses Motor will come to stop Nothing will happen to motor This will make armature to take heavy current, possibly burning it This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses Motor will come to stop ANSWER DOWNLOAD EXAMIANS APP
DC Motors Which one of the following is not the function of pole shoes in a D.C. machine? To spread out flux for better uniformity To reduce the reluctance of the magnetic path To reduce eddy current loss To support the field coils To spread out flux for better uniformity To reduce the reluctance of the magnetic path To reduce eddy current loss To support the field coils ANSWER DOWNLOAD EXAMIANS APP
DC Motors Which of the following motors is most suitable for signalling devices and many kinds of timers ? Reluctance motor C. shunt motor C. series motor Induction motor Reluctance motor C. shunt motor C. series motor Induction motor ANSWER DOWNLOAD EXAMIANS APP
DC Motors Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors? Stability Wide speed range High starting torque Low cost Stability Wide speed range High starting torque Low cost ANSWER DOWNLOAD EXAMIANS APP
DC Motors Carbon brushes are preferable to copper brushes because _____ They have longer life They reduce sparking They reduce armature reaction They have lower resistance They have longer life They reduce sparking They reduce armature reaction They have lower resistance ANSWER DOWNLOAD EXAMIANS APP
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