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 Can be used for 50°C ambient temperature also 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 Of higher H.P. should be selected Can be used for 50°C ambient temperature also 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 Of higher H.P. should be selected ANSWER DOWNLOAD EXAMIANS APP
DC Motors The shaft torque in a dc motor is less than total armature torque because of ______ in the motor. Cu losses Iron and friction losses None of the listed here Field losses Cu losses Iron and friction losses None of the listed here Field losses ANSWER DOWNLOAD EXAMIANS APP
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 For constant torque drive which speed control method is preferred? Armature voltage control Field control Shunt armature control Mechanical loading system Armature voltage control Field control Shunt armature control Mechanical loading system ANSWER DOWNLOAD EXAMIANS APP
DC Motors The main disadvantage of the Ward-Leonard control method is All of these High initial cost Low efficiency at high loads High maintenance cost All of these High initial cost Low efficiency at high loads High maintenance cost ANSWER DOWNLOAD EXAMIANS APP
DC Motors If a dc motor is comnected across the AC supply it will Run at lower speed Not run Run at normal speed Burn due to heat produced in the field winding by eddy currents Run at lower speed Not run Run at normal speed Burn due to heat produced in the field winding by eddy currents ANSWER DOWNLOAD EXAMIANS APP
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