For a DC Shunt Motor having armature resistance of 0.5 Ω and 2 A armature current at no-load, when the armature current is changed to 20 A at loaded condition the speed is 1000 r.p.m. What is the speed at no-load? none of above. 4575.4 r.p.m. 1130 r.p.m. 1037.5 r.p.m. TRUE ANSWER : ? YOUR ANSWER : ?
With the increase in speed of DC motor Back emf increase but line current falls. Both back emf as well as line current increase. Both back emf as well as line current fall. Back emf falls and line current increase. TRUE ANSWER : ? YOUR ANSWER : ?
Slot wedges in a dc machine is made up of cast iron. silicon steel. mild steel. fibre. TRUE ANSWER : ? YOUR ANSWER : ?
In most condition which frame of motor will be preferred? Open type. Splash proof. Totally enclosed fan coiled. Drip proof. TRUE ANSWER : ? YOUR ANSWER : ?
No load test of 3-phase induction motor gives which of the following? both A and B constant loss None of these variable loss TRUE ANSWER : ? YOUR ANSWER : ?
In a three phase slip-ring induction motor, brushes are connected to 3 - Φ AC supply. external star-connected resistors. DC supply. equalizing coils. TRUE ANSWER : ? YOUR ANSWER : ?
A DC compound motor has only series field winding. both shunt and series field winding. tertiary winding. only shunt field winding. TRUE ANSWER : ? YOUR ANSWER : ?
For a fault at the terminal of a synchronous generator, the fault current is maximum for a line to line fault. 3 - phase fault. line to ground fault. 3 - phase to ground fault. TRUE ANSWER : ? YOUR ANSWER : ?
The armature core of a DC machine is laminated to minimise temperature rise mechanical loss eddy-current loss hysteresis loss TRUE ANSWER : ? YOUR ANSWER : ?
A 3-phase, 2 pole, 12 slot synchronous machine is operating at synchronous speed. Find the slot angle? 18° 60° 30° 20° TRUE ANSWER : ? YOUR ANSWER : ?