DC Motors Carbon brushes are preferable to copper brushes because _____ They have lower resistance They reduce armature reaction They have longer life They reduce sparking They have lower resistance They reduce armature reaction They have longer life They reduce sparking 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 Induction motor C. series motor Reluctance motor C. shunt motor Induction motor C. series motor ANSWER DOWNLOAD EXAMIANS APP
DC Motors When two dc series motor are commected in parallel, the resultant speed is Loss than the normal speed Normal speed Zero More than the normal speed Loss than the normal speed Normal speed Zero More than the normal speed ANSWER DOWNLOAD EXAMIANS APP
DC Motors The direction of rotation of a D.C. series motor can be changed by Interchanging field terminals Interchanging supply terminals Either of (A) and (B) above None of these Interchanging field terminals Interchanging supply terminals Either of (A) and (B) above None of these ANSWER DOWNLOAD EXAMIANS APP
DC Motors The back emf in a dc motor ______ Aids the applied voltage Opposes the applied voltage None of the listed here Aids the armature current Aids the applied voltage Opposes the applied voltage None of the listed here Aids the armature current ANSWER DOWNLOAD EXAMIANS APP
DC Motors If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens This will make armature to take heavy current, possibly burning it Motor will come to stop This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses Nothing will happen to motor This will make armature to take heavy current, possibly burning it Motor will come to stop This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses Nothing will happen to motor ANSWER DOWNLOAD EXAMIANS APP
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