DC Motors The rheostatic speed control method is very Economical Unsuitable for rapidly changing loads Efficient Suitable for getting speeds above the normal Economical Unsuitable for rapidly changing loads Efficient Suitable for getting speeds above the normal ANSWER DOWNLOAD EXAMIANS APP
DC Motors If a dc motor is comnected across the AC supply it will Run at lower speed Run at normal speed Burn due to heat produced in the field winding by eddy currents Not run Run at lower speed Run at normal speed Burn due to heat produced in the field winding by eddy currents Not run ANSWER DOWNLOAD EXAMIANS APP
DC Motors In dc machines fractional pitch winding is used To reduce the generated emf To reduce the sparking To increase the generated emf To improve cooling To reduce the generated emf To reduce the sparking To increase the generated emf To improve cooling ANSWER DOWNLOAD EXAMIANS APP
DC Motors In the dc motor the iron losses occur in Brushes Field Commutator Armature Brushes Field Commutator Armature ANSWER DOWNLOAD EXAMIANS APP
DC Motors In variable speed motor A weaker commutating field is needed at low speed than at high speed A stronger commutating field is needed at low speed than at high speed None of these Same commutating field is needed at low speed than at high speed A weaker commutating field is needed at low speed than at high speed A stronger commutating field is needed at low speed than at high speed None of these Same commutating field is needed at low speed than at high speed ANSWER DOWNLOAD EXAMIANS APP
DC Motors As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit Armature is temporarily open circuited A resistance is connected in series with armature A resistance is connected parallel to the armature A high value resistor is connected across the field winding Armature is temporarily open circuited A resistance is connected in series with armature A resistance is connected parallel to the armature A high value resistor is connected across the field winding ANSWER DOWNLOAD EXAMIANS APP
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