Electrical Machines A cumulatively compounded dc motor delivers rated load power at rated speed. If the series field is short-circuited, then Ia increases and ωm decreses both decrese both armature current Ia and speed ωm increase Ia remains constant but ωm increase Ia increases and ωm decreses both decrese both armature current Ia and speed ωm increase Ia remains constant but ωm increase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 240 V dc series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3 Ω. The value of resistance which must be added to obtain rated torque at 1000 rpm is 6 Ω 2.2 Ω 5.7 Ω 1.9 Ω 6 Ω 2.2 Ω 5.7 Ω 1.9 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC series motor drawing an armature current of Ia is operating under saturated magnetic conditions. The torque developed in the motor is proportional to Ia2 I/Ia2 1/Ia Ia Ia2 I/Ia2 1/Ia Ia ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor runs at a no-load speed of 1140 rpm. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full-load speed in rpm is 1203 1080 1200 1000 1203 1080 1200 1000 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor has external resistance Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping Ra minimum and Rf minimum Ra maximum and Rf maximum Ra maximum and Rf minimum Rf maximum and Ra minimum Ra minimum and Rf minimum Ra maximum and Rf maximum Ra maximum and Rf minimum Rf maximum and Ra minimum ANSWER DOWNLOAD EXAMIANS APP
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