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 both decrese both armature current Ia and speed ωm increase Ia increases and ωm decreses Ia remains constant but ωm increase both decrese both armature current Ia and speed ωm increase Ia increases and ωm decreses ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The slight curvature at the lower end of the OCC of a self excited DC generator is due to residual flux. magnetic inertia. high speed. high field resistance. residual flux. magnetic inertia. high speed. high field resistance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Under which of the following conditions is a dc motor provided with compensating winding used ? 1. Wide range of speed control above normal 2. Wide range of steady load variation with no speed control 3.Wide range of rapid variation in load Select the correct answer using the codes given below : Codes : 1 and 3 1, 2 and 3 2 and 3 1 and 2 1 and 3 1, 2 and 3 2 and 3 1 and 2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again 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 field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the supply terminal of a DC shunt motor are interchanged The motor will stop. The motor will run much faster in the same direction. The direction of rotation will reverse. The motor will run at its normal speed in the same direction as before. The motor will stop. The motor will run much faster in the same direction. The direction of rotation will reverse. The motor will run at its normal speed in the same direction as before. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A large series motor is never started without some mechanical load on it because otherwise it will develop excessive speed and damage itself. draw too much current. open fuse or circuit breaker. produce sparking at brushes. develop excessive speed and damage itself. draw too much current. open fuse or circuit breaker. produce sparking at brushes. ANSWER DOWNLOAD EXAMIANS APP
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