A 25 H.P. 230V 3-phase motor has a full load amperage of 68 amps at a 79% power factor. Determine the motors: Total kVA=

v. With reference to an 50 Hz3 phase alternator explain how P,Q,V and F are controlled.

(b) A 4-pole 3 phase alternator is driven at 1200 rpm. What is the frequency of the output voltage of the alternator? Explain how the same alternator can be used to generate voltage at 50 Hz.

D6

A single phase alternator has a rated output of 500 KVA at a terminal voltage of 3300 V. The stator winding has a resistance of 0.6 ohm and synchronous reactance of 4 ohms. Calculate the voltage regulation for full load at a pf (i) unity (ii) 0.8 leading (ii) 0.8 lagging

answer in 4 decimal places.

An alternator is a type of alternating current generator that is electromechanical. 1. True 2. False

When 40V DC voltage is applied to a single-phase AC motor, it draws 1A current. When 200v-50Hz AC is applied to the same motor, it draws 4A current.Calculate the capacity of the capacitor to be connected in parallel to make the power factor 0.9, and in this case the circuit current?

A dc generator has no load output voltage of 120V. Its armature circuit resistance is 0.95 ohm and its field coils are separately energized. If the load is rated 2000 watts at 115V, what power could be delivered to the load?

3.The voltage generated across one inductor of an alternator is 8.11V. There are 120 slots and 4 turns in every coil. The conductors are all in series and connected in double layer lap windings distributed sinusoidally in several slots. The coil pitch is 10 slots, frequency is 60 Hz and synchronous speed is 720 rpm. Calculate the line-to-line generated voltage if the alternator windings are connected wye. a. 2400Vb. 4160Vc. 4800Vd. 856V