Questions

Why does emf lag flux?

Why does emf lag flux?

Explanation: The opposition is offered at its maximum level when the angle between first and second flux is 90°. The opposition is offered at its maximum level when the angle between first and second flux is 90°. Therefore ,the emf produced will always lag the flux linkage(Number of turns* flux) by 90°.

Why the magnitude of induced emf in an alternator is dependent upon speed of the rotor and the magnitude of field current?

Due to relative motion between armature conductors and the main field, an emf is induced in the armature windings whose magnitude depends upon the relative speed and as well as the magnetic flux.

What is the relation between the emf phasor and flux phasor in a synchronous machine?

Whenever the magnetic structure of a cylindrical rotor synchronous machine is subjected to rotating mmf vector, it is seen as an mmf phasor from the stator with its flux phasor in phase with it, while the phasor representing the phase emf induced lags behind both these phasors by 90° (see Fig. 8.3).

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Which emf is induced in armature winding?

As conductor rotates in a magnetic field, the voltage component at various positions is different. Hence the basic nature of induced emf in the armature winding in case of dc generator is alternating….Induced emf.

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What is armature reaction What is the relation between induced emf and armature voltage for motoring and generating action?

The back emf opposes the supply voltage. The supply voltage induces the current in the coil which rotates the armature. The electrical work required by the motor for causing the current against the back emf is converted into mechanical energy. And that energy is induced in the armature of the motor.

What is the angle between the induced voltage and supply voltage in a synchronous motor under running conditions?

From the phasor, it clear that the angle between the induced voltage (ER) and supply voltage (V) of a synchronous motor (θ – ϕ) under running conditions is greater than zero but less than 90°.