A 11,000/6,600 V, 3-þ, transformer has a star-connected primary and a delta-connected secondary. It supplies a 6.6. kV motor having a star-connected stator, developing 969.8 kW at a power factor of 0.9 lagging and an efficiency of 92 per cent. Calculate (a) motor line and phase currents (b) transformer secondary current and (c) transformer primary current. [(a) Motor: IL = Joh = 126.3 A (b) phase current 73 A (c) 75.8] %3D

A 11,000/6,600 V, 3-þ, transformer has a star-connected primary and a delta-connected secondary. It supplies a 6.6. kV motor having a star-connected stator, developing 969.8 kW at a power factor of 0.9 lagging and an efficiency of 92 per cent. Calculate (a) motor line and phase currents (b) transformer secondary current and (c) transformer primary current. [(a) Motor: IL = Joh = 126.3 A (b) phase current 73 A (c) 75.8] %3D

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.63P: A 23/230-kV step-up transformer feeds a three-phase transmission line, which in turn supplies a...

See similar textbooks

Similar questions

For an ideal transformer, the efficiency is (a) 0 (b) 100 (c) 50
Consider the three single-phase two-winding transformers shown in Figure 3.37. The high-voltage windings are connected in Y. (a) For the low-voltage side, connect the windings in , place the polarity marks, and label the terminals a, b, and c in accordance with the American standard. (b) Relabel the terminals a, b, and c such that VAN is 90 out of phase with Va for positive sequence.
For a short-circuit test on a 2-winding transformer, with one winding shorted, can you apply the rated voltage on the other winding? (a) Yes (b) No
A 23/230-kV step-up transformer feeds a three-phase transmission line, which in turn supplies a 150-MVA,0.8 lagging power factor load through a step-down 230/23-kV transformer. The impedance of the line and transformers at 230kVis18+j60. Determine the tap setting for each transformer to maintain the voltage at the load at 23 kV.
An ideal transformer has no real or reactive power loss. (a) True (b) False
The symbol shown is a(n) a. iron core transformer. b. auto transformer. c. current transformer. d. air core transformer.
For an ideal 2-winding transformer, an impedance Z2 connected across winding 2 (secondary) is referred to winding 1 (primary) by multiplying Z2 by (a) The turns ratio (N1/N2) (b) The square of the turns ratio (N1/N2)2 (c) The cubed turns ratio (N1/N2)3
(a) An ideal single-phase two-winding transformer with turns ratio at=N1/N2 is connected with a series impedance Z2 across winding 2. If one wants to replace Z2, with a series impedance Z1 across winding 1 and keep the terminal behavior of the two circuits to be identical, find Z1 in terms of Z2. (b) Would the above result be true if instead of a series impedance there is a shunt impedance? (c) Can one refer a ladder network on the secondary (2) side to the primary (1) side simply by multiplying every impedance byat2 ?
a 1000 kva 24,000/2400-v single- phase transformer at 40 per turn. find the number of turns on each winding and the current rating of each winding. a. turns on 24.000 v winding b. turns on 2.4000 v winding
6. 150 kVA, 2800-240 V, 50 Hz transformer. Regis = 0.0082N , Xeq.Ls = 0.0223N RfcHs=2200N Step down transformer delivers 135 kW to a load at 0.9 lagging power factor at rated voltage. Determine the Following: a) Terminal voltage (LV side). b) Terminal voltage (HV side). c) High side current. d) Input impedance. e) Voltage regulation. f) Efficiency. g) Voltage regulation for 0.9 leading pf. h) Draw the phasor diagram of secondary circuit at 0.9 lagging pf. i) Draw the phasor diagram of secondary circuit at 0.9 leading pf. XmHs=12002
2.Fringing effect is a phenomena occurs in... (a)Transformers. (b) Electrical field. (c) Air gap (d) All of the above. 3. The kVA rating of an ordinary 2-winding transformer is increased when connected as an autotransformer because (a) transformation ratio is increased (b) secondary voltage is increased (c) energy is transferred both inductively and conductivity (d) secondary current is increased. 4. The....... of the hysteresis loop is a measure of energy lost per cycle (a) area. (b) Type. (c) Frequency (d) No one of the above. 5. At relatively light loads, transformer efficiency is low because (a) secondary output is low (b) transformer losses are high (c) fixed loss is high in proportion to the output (d) Cu loss is small. 6. In an ideal transformer, (a) windings have no resistance (b) core has no losses (c) core has infinite permeability (d) all of the above. 7. In electromagnetic circuits, path of eddy current is........ (a) Parallel to the path of the flux. (b) Perpendicular to…
The test results of a 5 kVA, 400/200 V, 50 Hz, single phase transformer are as follows. O.C. Test: 400 V, 1 A, 50 W, H.V. side S.C. Test: 12 V, 12.5 A, 60 W, H.V. side Find the full load efficiency and regulation when the power factor is 0.8 lagging.