Electrical Machines In a synchronous machine, if φ is the flux per pole and f is the frequency of the emf induced E then E ∝ 1/(φf) E ∝ φf E ∝ φ/f E ∝ f/φ E ∝ 1/(φf) E ∝ φf E ∝ φ/f E ∝ f/φ ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop synchronous motor torque. induction generator torque. DC motor torque. induction motor torque. synchronous motor torque. induction generator torque. DC motor torque. induction motor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The current drawn by the a 230 V DC motor of armature resistance 0.5 Ω and back emf 200 V is 40 60 660 600 40 60 660 600 ANSWER DOWNLOAD EXAMIANS APP
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 armature connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC generator, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will deteriorate with rise in terminal voltage. improve with fall of terminal voltage. improve with rise in terminal voltage. deteriorate with fall of terminal voltage. deteriorate with rise in terminal voltage. improve with fall of terminal voltage. improve with rise in terminal voltage. deteriorate with fall of terminal voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Sparkless commutation can be achieved by employing high resistance carbon brushes. compensating winding. inter poles. any one or more of the above methods. high resistance carbon brushes. compensating winding. inter poles. any one or more of the above methods. ANSWER DOWNLOAD EXAMIANS APP
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