.150KVA, 440 V, 50 Hz, star-connected diesel generator has armature reaction 1.6 S2 when it is supplying rated current at 0.8 p.f lagging. If the armature resistance is 0.3 and self-reactance half the effect of armature reaction determine (a) the no-load voltage when the load is disconnected and (b) the no-load voltage when the alternator terminals are short circuited.

.150KVA, 440 V, 50 Hz, star-connected diesel generator has armature reaction 1.6 S2 when it is supplying rated current at 0.8 p.f lagging. If the armature resistance is 0.3 and self-reactance half the effect of armature reaction determine (a) the no-load voltage when the load is disconnected and (b) the no-load voltage when the alternator terminals are short circuited.

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter2: Fundamentals

Section: Chapter Questions

Problem 2.21P: An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor...

See similar textbooks

Similar questions

A 3-phase, star -connected turbo-alternator, having a synchronous reactance of 10 Ω per phase and negligible armatureresistance, has an armature current of 220 A at unity p.f. The supply voltageis constant at 11 kV at constant frequency. If the steam admission is unchangedand the e.m.f. raised by 25%, determine the current and power factor.
Show that an alternator running in parallel on constant-voltage and frequency bus-bars has a natural time period of oscillation. Deduce a formula for the time of one complete oscillation and calculate its value for a 5000-kVA, 3-phase, 10,000-V machine running at 1500 r.p.m. on constant 50-Hz bus-bars. The moment of inertia of the whole moving system is 14,112 kg-m2 and the steady short-circuit is five times the normal full-load value. ANSWER IS [1.33 second]
A single-phase alternator connected to 6,600-V bus-bars has a synchronous impedance of 10Ω and a resistance of 1 Ω. If its excitation is such that on open circuit the p.d. would be 5000 V, calculate the maximum load the machine can supply to the external circuit before dropping out of step and the corresponding armature current and p.f. [2864 kW, 787 A, 0.551]
A short shunt compound generator supplies a load of 10 kW at 200 V through a pair of feeder and series field resistance 0.10 ohm. Armature resistance, shunt field resistance and series field resistance are 0.01 ohm, 52.2 ohms and 0.10 ohm, respectively. If the core friction and windage losses amount to 631 watts, the BHP of the driving engine is nearest to
The synchronous reactance of the direct-axis and quadrature-axis of a three-phase,40-pole, 50 Hz, 13,8 kV, salient-pole synchronous generator is 2,38 Ω and 1,33 Ωrespectively. The resistance of the star-connected stator is negligible. The load angle ofthe machine is 30°e and the excitation is set to induce an emf of 167%. Sketch the phasordiagram and calculate:(a) current(b) power(c) reluctance torque(d) the maximum load angle(e) the maximum power developed
a 20MVA, 12.2KV, 0.8 PF lagging Y- connected SG has a negligible armature resistance and syn. Reactance of 8.2Ω, the generator is connected in parallel with a 60Hz 12.2Kv infinite bus that is capable of supplying any real or reactive power with no change in frequency or terminal voltage. A) find the internal generated voltage at rated condition. B) what is the armature rated current. C) suppose that the generator is initially operating at rated condition. If the internal generated voltage is decreased by 5%, what is will be the new armature current?
A 50 kVA, 500 V, single phase alternator gives 700 V on open circuit at the field current of 15 A. While on short circuit a short current of 375 flows for the same field current. Assuming the armature resistance of 0.8 ohm, calculate (1) Synchronous impedance and (2) synchronous reactance
Two similar 6600 V, 3-phase alternators are running in parallel sharing equally a total load of 10,000 kW at a lagging power factor of 0.8, the two machines being similarly excited. If the excitation of one machine is adjusted so that its armature current is 438 A, find the armature current and power factor of the second machine if the steam supply is not changed. [Ans. cos Ꝋ2 = 0.568 (lag)]
2.2 A three-phase synchronous generator has a reactance of 1.5 p.. and negligible resistance. It supplies a rated current of 1.0 p.. at 1.0 p.u. terminal voltage to a lagging load of 0.9 power factor. Determine the rated excitation voltage in p.u. and the internal load angle. Construct the performance chart of the generator in 2.1 (above) assuming its rating is 450 MVA.
A 500-V, 50-kVA, single-phase alternator has an effective resistance of 0.2 Ω. A field current of 10A produces an armature current of 200A on short-circuit and emf of 450V on open circuit. Calculate (a) the synchronous impedance and reactance and (b) the full-load regulation with 0.8 p.f. lagging.
A 3-phase, wye connected alternator rated at 1600 kVA, 13.5 kV. The effective armature resistance and synchronous reactance are 1.5 ohms and 30 ohms, respectively. What is the percent regulation for a load of 1280 kW at 0.80 leading power factor?
A 10-kVA, 380-V, 60-Hz, 2-pole, three-phase, Y-connected, synchronous generator delivers the rated load at 0.8 pf lagging. The synchronous impedanceis 1.2 + j4 Ohm/phase. Determine (a) the synchronous speed, (b) the generated voltage per phase, (c) the power angle, (d) voltage regulation, and (e) the efficiency if the rotations loss is 1 kW.