A 25 kVA, 400 V, –connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is ___________.

A star connected 400V, 50Hz, 4 pole synchronous machine gave the following open circuit and short circuit test results:

Open circuit Test: at field current

Short circuit Test:  at field current

The value of per phase synchronous impedance in at rated voltage is______________.

A field excitation of 20 A in a certain alternator results in an armature current of 400 A in short Circuit and a terminal voltage of 2000 V on open circuit. The magnitude of the internal voltage drop within the machine at a load current of 200 A is

A 100 kVA, 415V (line), star-connected synchronous machine generates rated open circuit voltage of 415 V at a field current of 15 A. The short circuit armature current at a field current of 10A is equal to the rated armature current. The per unit saturated synchronous reactance is         

Higher synchronous reactance is preferred in the present day alternators, because one can have

In figure the characteristic that corresponds to the variation of synchronous reactance of a synchronous motor with field current is

A three phase alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed a field current of  is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current

A 500 MVA, 11 KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance on the base values of 100 MVA and 22 KV is: