Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A cumulatively compounded dc motor delivers rated load power at rated speed. If the series field is short-circuited, then 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 Ia increases and ωm decreses both decrese both armature current Ia and speed ωm increase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A separately-excited DC generator, running at rated speed, has 6 volts across its armature terminals with no field current. When field winding is excited with one ampere, the voltage builds up to 250 V at no load. In case field current is reduced to zero, with the speed remaining unaltered, the armature terminal voltage would be 6 V more than 6 V zero less than 6 V 6 V more than 6 V zero less than 6 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines stepped cores are used in transformers in order to reduce iron loss. volume of copper. volume of iron. reluctance of core. iron loss. volume of copper. volume of iron. reluctance of core. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The use of double squirrel cage winding on the rotor provides higher efficiency. reduced starting torque. a large starting torque. low noise. higher efficiency. reduced starting torque. a large starting torque. low noise. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous motor electromagnetic power varies None of these directly as square of applied voltage inversely as applied voltage directly as applied voltage None of these directly as square of applied voltage inversely as applied voltage directly as applied voltage ANSWER DOWNLOAD EXAMIANS APP