A single phase transformer rated 30 kVA, 1200/120 V is connected as an autotransformer to supply 1320V from a 1200 V bus (a) Draw a diagram of the transformer connections showing the polarity marks on the windings and directions chosen as positive for current in each winging so that the currents will be in phase. (b) Mark on the diagram the values of rated rated in the windings and at the input and output. (c) Determine the rated kVA of the unit as an autotransformer (Ctr) -

A single phase transformer rated 30 kVA, 1200/120 V is connected as an autotransformer to supply 1320V from a 1200 V bus (a) Draw a diagram of the transformer connections showing the polarity marks on the windings and directions chosen as positive for current in each winging so that the currents will be in phase. (b) Mark on the diagram the values of rated rated in the windings and at the input and output. (c) Determine the rated kVA of the unit as an autotransformer (Ctr) -

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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13)This MCQ QUESTION FROM BASIC POWER ELECTRICAL ENGINEERING course.
4. 100 kVA, 6800-240 V, 50 Hz single phase step down transformer has the following parameters: RLs=0.0082 RHs=2.62 Rfe-HS=50002 XLs=0.015N XHs=5.2N Xm.Hs=88002 Transformer is delivering 80% of rated load at rated voltage and 0.95 lagging power factor. Determine the following: a) The equivalent impedance of the transformer referred to primary. b) Input impedance of the combined transformer and load. c) Actual input voltage at HV side. d) Input impedance if load is disconnected. e) Exciting current at no load.
Find the elements of the equivalent circuit attributed to the secondary of a single-phase transformer. The no-load voltages in the primary and secondary circuit are 200 volts and 400 volts, respectively, with a frequency of 50 Hz. The primary no-load current at the voltage of 200 volts is 0.7 amperes and the loss of the core is equal to 70 watts. The resistance and reactance of the primary are 3.2 ohms and 1.25 ohms, respectively. The resistance and reactance of the secondary are 0.6 ohm and 0.07 ohm, respectively. Draw the equivalent circle, showing the values of its elements.
A 36/240 V phase transformer, belonging to a phase measured from the no-load (idle) run and short-circuit test. values are given in the table below. High voltage by applying rated voltage to the low voltage winding (The winding ends were left unloaded and the results of the no-load test results were obtained. By applying nominal current to the high voltage windings, the low voltage windings were short-circuited, and the results of the short circuit test were obtained. In direct current test 1 V direct voltage is applied to the low voltage winding, and the transformer draws 500 A direct current. All equivalent Calculate the circuit elements as moved to the low voltage side. Idle run test: Voltage : 36V Power : 68W Current : 2,8A Short circuit test: Voltage : 15V Power : 325W Current : 42,2A
Q5:Choose the correct answer from the given alternatives (answer five only) 1.In an ideal transformer, (a) windings have no resistance (b) core has infinite permeability (d) all of the above. (c) core has no losses 2. The primary and secondary induced e.m.fs. El and E2 in a two-winding transformer are always: (a) equal in magnitude (b) in-phase with each other (c) antiphase with each other (d) determined by load on transformer secondary. 3. In relation to a transformer, the ratio 20 : 1 indicates that (a) there are 20 turns on primary one turn on secondary (b) secondary voltage is 1/20th of primary voltage (c) primary current is 20 times greater than the secondary current. (d) for every 20 turns on primary, there is one turn on secondary. 4. A transformer has negative voltage regulation when its load power factor is: (a) zero (b) lagging. (d) unity (c) leading
High voltage engineering
A 3.5 kV / 120V, 50 Hz, single phase transformer is to have an approximate e.m.f per turn of 33V and operate with a maximum flux density of 1.35T. Determine, (a) The number of primary and secondary turns. (b) The cross sectional area of the core.
Choose the correct answer from the given alternative: 1. In an ideal transformer, (a) windings have no resistance (c) core has no losses (b) core has infinite permeability (d) all of the above. 2. The primary and secondary induced e.m.fs. El and E2 in a two-winding transformer are always: (a) equal in magnitude (b) in-phase with each other (c) antiphase with each other (d) determined by load on transformer secondary. 3. In relation to a transformer, the ratio 20: 1 indicates that (a) there are 20 turns on primary one turn on secondary (b) secondary voltage is 1/20th of primary voltage (c) primary current is 20 times greater than the secondary current. (d) for every 20 turns on primary, there is one turn on secondary. 4. A transformer has negative voltage regulation when its load power factor is: (a) zero (b) lagging. (d) unity (c) leading 5. During short-circuit test, the iron loss of a transformer is negligible because: (a) the entire input is just sufficient to meet Cu losses only…
In a single phase transformer when all parameter is shifted to primary side value of primary side resistance is 0.5 ohm and resistance which is shifted from secondary to primary is also 0.5 ohm. If full load current in primary side is 20(A) what is total copper loss in transformer.
NEAT EXPLAIN NEEDED( CORRECT ANSWER NO GPT PLEASE)
5. Write down the equations of a single phase transformer at no-load mode. Give the names of the resistances, reactance, e.m.f.'s, currents and voltages.