Alternators MCQs

For a uniformly distributed winding of an alternator with a phase spread of 13 degrees, the distribution factor is

A single-phase alternator has a synchronous reactance of 2 ohms and negligible resistance. If it supplies 10 A to a purely capacitive load at 200V, then the generated emf will be

Suppose a synchronous generator connected to an infinite bus is supplying electrical power at unity PF to the bus. If its field current is now increased.sinp

In the phasor-diagram of a round-rotor synchronous generator, the voltage equations is Et. =V + la (ra + jXs), where Et- = excitation voltage, Vt = terminal voltage, Ta = armature current at lagging power factor, ra = armature resistance; Xs = synchronous reactance. While remaining synchronized to the bus-bars (infinite bus), if th power input from the prime mover is gradually decreased and finally stopped, it will result in

In a synchronous machine, the electric circuits are armature circuit, field circuit and damper circuit and Xd is d-axis synchronous reactance; X'd is d-axis transient synchronous reactance and X"d is d-axis sub-transient synchronous reactance. If there is no damper winding,then

An alternator of 400 kW is driven by a prime mover of speed regulation 4% and another alternator of 200 km is driven by a prime mover of speed regulation 3%. The total load they can take, without overloading either of the machines is

Consider the following statements : Modern alternators are designed for large airgap to have 1. large inherent regulation. 2. very stable parallel operation. 3. higher stability limit. 4. sinusoidal mmf distribution. Which of these statements are correct?

To calculate the full-load voltage regulation of a synchronous generator at any power factor using mmf method, it is required to have

An alternator is operating on infinite bus. It will develop maximum synchronizing power when it is operating at