The system parameter of a induction machine is 39Nm/A2 and its rated voltage is 96V

The system parameter of a induction machine is 39Nm/A2 and its rated voltage is 96V. When it is kept in motion alternatively.(i.e. speed is zero alternately), the armature current is Ia can only be increased up to 5v so that the voltage supplied to the stator terminals reaches its rated value of 40V. The machine is mechanical and excitation losses are negligible.

Consider the following:

Calculate the rated torque, impedance, output power, stator voltage, power factor for this machine.

An external resistance R is placed in series with the armature-field circuit in order to improve motor excitation to 15 rad/s while Ia has the rated value of 33A and the load torque is at the rated value. Calculate the inductive impedance and the power loss in stator winding. Without presenting any calculation, explain how this value of impedance is adjusted so that the machine comes to a halt (i.e stops rotating)? The field form of a 3-phase, 50 Hz, 10-pole, star connected alternator has a spatial flux density distribution given by the expression B = Sin?θ? + 0.3sin3?θ? + 0.2sin?5θ? + 0.1sin7?θ? T.

The flux density wave of a alternator consists of a fundamental a 25% third harmonic.

(i)Calculate the percentage increase in the phase voltage due to the harmonic?

(ii) Draw the complete phasor diagram & show that for alternator operation, the field pole must be ahead of the resultant air-gap field?

(iii)Calculate the rms line voltage when the when the alternator winding's are in a)star, b)delta?

(iv)The alternator has synchronous impedance of (0 + 3j). Determine the load angle andd the excitation emf of the alternator?

(v)Calculate the full load armature emf?

(vi) Calculate the percentage regulation for a load of 1280kw at power factor of (a)0. leading b)unity, (c) 0.8 lagging?

A balanced star-delta connected purely capacitive load is at the secondary of a star-delta synchronous motor which is in unsync of induction motor. The ventilating ducts have been provided by stator core. The field excitation of 100 A in a certain level results in armature current of 200A in short circuit and a terminal voltage of 400V on open circuit.

1. Design the characteristic equation of the developed impedance?

2. Draw the circuit diagram of the whole system?

3. Find and active and reactive system?

4. The per unit saturated synchronous reactance?

5. The magnitude of the internal voltage drop?

6. The effective impedance of equivalent generator?

7. The per unit characteristics of whole system?