DC Motors Carbon brushes are preferable to copper brushes because _____ They have lower resistance 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 ANSWER DOWNLOAD EXAMIANS APP
DC Motors The main disadvantage of the Ward-Leonard control method is High initial cost High maintenance cost Low efficiency at high loads All of these High initial cost High maintenance cost Low efficiency at high loads All of these ANSWER DOWNLOAD EXAMIANS APP
DC Motors In variable speed motor Same 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 A weaker commutating field is needed at low speed than at high speed Same 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 A weaker commutating field is needed at low speed than at high speed ANSWER DOWNLOAD EXAMIANS APP
DC Motors The friction and windage losses in a dc motor depends upon Field and armature resistance Flux Speed Armature current Field and armature resistance Flux Speed Armature current ANSWER DOWNLOAD EXAMIANS APP
DC Motors The resistance of shunt field winding as compared to series field winding is More None of the listed here Less The same More None of the listed here Less The same ANSWER DOWNLOAD EXAMIANS APP
DC Motors If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor Of higher H.P. should be selected Is to be de-rated by a factor recommended by manufacturer and select the next higher H.P. motor Of lower H.P. should be selected Can be used for 50°C ambient temperature also Of higher H.P. should be selected Is to be de-rated by a factor recommended by manufacturer and select the next higher H.P. motor Of lower H.P. should be selected Can be used for 50°C ambient temperature also ANSWER DOWNLOAD EXAMIANS APP
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