The full load current of a transformer with 5% impedance is 500 amperes. The expected short-circuit...
The full load current of a transformer with 5% impedance is 500 amperes.
The expected short-circuit current at the main switchboard is?
Note: For simplicity, a conservative approach is to assume that the utility power network serving this transformer is sufficiently large enough to have practically zero impedance during a fault.
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The full load current of a transformer with 5% impedance is 500
amperes.
The expected short-circuit...
A large transformer operating at no-load draws an exciting current of 5 A when the primary is connected to a 240 V, 50 Hz source (HELP)
Question 1: A large transformer operating at no-load draws an exciting current of 5 Awhen the primary is connected to a 240 V, 50 Hz source. From wattmeter testit is known that the iron losses are equal to 300 W. At short circuit the voltage applied is 24 Volts , the short-circuit current is 35 Amperes, the power meter reads 400 W. Calculate:i) The reactive power absorbed by the core;ii) The value of Rc and Xm of the magnetising branch; iii)...
single phase transformer with open circuit test and short circuit test
A 20 kVA, 12,000/380 V, single-phase transformer has the following test results:open circuit (low voltage side): V = 380, I = 2, P = 250short circuit (high voltage side): V = 200, I = 2.5, P = 250a)Determine the approximate equivalent circuit parameters of the transformer in per-unit values.b) the transformer is working at 80% full load with 0.85 power factor lagging. what is the secondary current at this working condition in both actual and per-unit values.
ASSIGNMENT Develop the internal impedance model for the provided transformer, using appropriate short circuit and open circuit test at rated current and voltage respectively. The auxiliary transf...
ASSIGNMENT Develop the internal impedance model for the provided transformer, using appropriate short circuit and open circuit test at rated current and voltage respectively. The auxiliary transformer is a General Electric JE-27 auxiliary potential transformer rated 240-120Vac and thermal rating of 150VA Please provide the model results as follows: - Ohms referred to the 240V side Ohms referred to the 120V side - Per Unit based on the auxiliary transformer rating of 240- 120V and 150VA.
ASSIGNMENT Develop the internal...
Transformer TI : 50 MVA, 10 kV Y/138 kV Y, X=0.10 per unit; Transformer T2: 100 MVA, 15 kV D/138 kV Y, X-0.10 per unit; Each 138-kV line: X1-400 A three-phase short circuit occurs at bus 5,...
Transformer TI : 50 MVA, 10 kV Y/138 kV Y, X=0.10 per unit; Transformer T2: 100 MVA, 15 kV D/138 kV Y, X-0.10 per unit; Each 138-kV line: X1-400 A three-phase short circuit occurs at bus 5, where the prefault voltage is 15 kV. Prefault load current is neglected. (a)Draw the positive-sequence reactance diagram in per-unit on a 100-MVA, 15-kV base in the zone of generator G2. Determine: (b) the The'venin equivalent at the fault, (c) the subtransient fault current...
4.70 A full-wave bridge-rectifier circuit with a 500-22 load operates from a 120-V (rms) 60-Hz household...
4.70 A full-wave bridge-rectifier circuit with a 500-22 load operates from a 120-V (rms) 60-Hz household supply through a 6-to-1 step-down transformer having a single Secondary winding. It uses four diodes, each of which can be modeled to have a 0.7-V drop for any current. What is the peak value of the rectified voltage across the load? For what fraction of a cycle does each diode conduct? What is the average voltage across the load? What is the average current...
Question 2: A large network supplies a three phase induction motor through a short feeder line. The following data are provided No-load Test Data: ho-load 480 V; Ino-load = SA; Pno-load 1.3 kw Blocke...
Question 2: A large network supplies a three phase induction motor through a short feeder line. The following data are provided No-load Test Data: ho-load 480 V; Ino-load = SA; Pno-load 1.3 kw Blocked-rotor Test Data: Volocked-rotor 52 V; Iblocked-rotor 34 A; Polocked-rotor 1.3 kw: frequencyblocked-Fotor 25 Hz Stator Resistance: Rstator 0.3529 n/mile; Length 3 miles (0.1+j0.56) Supply Feeder Data: Zfeeder HP: v,upply-440 V: Number of poles-4: Slip-2.5%; Ploss- 250 w a. Calculate the magnetizing impedance of the three phase...
1. Transformer with three legs A, B and C in case of homogenous the first leg...
1. Transformer with three legs A, B and C in case of homogenous
the first leg A has coil with 3 Henry, what is the Henry at leg
C
a. 0.5 H
b. 1 H
c. 2 H
d. 2.5 H
2. If a carrier wave of 10MHz is amplitude modulated by an audio
signal of 1 kHz, the resultant signal to be broadcast contains only
the:
(A) 10,001,000-Hz component
(B) 10,001,000-Hz and 9,999,000-Hz components
(C) 10,001,000-Hz, 10,000,000-Hz, and 9,999,000-Hz...
help me please please answer many as possible 10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iro...
help me please
please answer many as possible
10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iron core. C. using grain-oriented-steel D, reducing the connected load. 11. In Fig. 1(b) in the text, the phasor I, It is the resultant of the A. exciting and the magnetizing current. B. active and the reactive secondary current. C. primary and the exciting current. D....
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative-...
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative- and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn = 0.05 per unit on the motor base. The per-unit zero-, positive and negative-sequence networks on a 100-MVA is shown in Figure P26, 13.8-kV base in the zone of the generator. a. Reduce the sequence networks to their...
A three phase induction motor draws a starting current which is five times the full load...
A three phase induction motor draws a starting current which is five times the full load current with direct on line starting, while developing twice the full load torque. Q2.1. Based on the two facts that starting current is proportional to the applied voltage and that the starting torque is proportional to the square of the applied voltage, determine voltage (as a per cent of rated voltage) required to obtain a starting torque equalling the full load torque. (10 marks)...
ASSIGNMENT Develop the internal impedance model for the provided transformer, using appropriate short circuit and open circuit test at rated current and voltage respectively. The auxiliary transformer is a General Electric JE-27 auxiliary potential transformer rated 240-120Vac and thermal rating of 150VA Please provide the model results as follows: - Ohms referred to the 240V side Ohms referred to the 120V side - Per Unit based on the auxiliary transformer rating of 240- 120V and 150VA.
ASSIGNMENT Develop the internal...
Transformer TI : 50 MVA, 10 kV Y/138 kV Y, X=0.10 per unit; Transformer T2: 100 MVA, 15 kV D/138 kV Y, X-0.10 per unit; Each 138-kV line: X1-400 A three-phase short circuit occurs at bus 5, where the prefault voltage is 15 kV. Prefault load current is neglected. (a)Draw the positive-sequence reactance diagram in per-unit on a 100-MVA, 15-kV base in the zone of generator G2. Determine: (b) the The'venin equivalent at the fault, (c) the subtransient fault current...
4.70 A full-wave bridge-rectifier circuit with a 500-22 load operates from a 120-V (rms) 60-Hz household supply through a 6-to-1 step-down transformer having a single Secondary winding. It uses four diodes, each of which can be modeled to have a 0.7-V drop for any current. What is the peak value of the rectified voltage across the load? For what fraction of a cycle does each diode conduct? What is the average voltage across the load? What is the average current...
Question 2: A large network supplies a three phase induction motor through a short feeder line. The following data are provided No-load Test Data: ho-load 480 V; Ino-load = SA; Pno-load 1.3 kw Blocked-rotor Test Data: Volocked-rotor 52 V; Iblocked-rotor 34 A; Polocked-rotor 1.3 kw: frequencyblocked-Fotor 25 Hz Stator Resistance: Rstator 0.3529 n/mile; Length 3 miles (0.1+j0.56) Supply Feeder Data: Zfeeder HP: v,upply-440 V: Number of poles-4: Slip-2.5%; Ploss- 250 w a. Calculate the magnetizing impedance of the three phase...
1. Transformer with three legs A, B and C in case of homogenous
the first leg A has coil with 3 Henry, what is the Henry at leg
C
a. 0.5 H
b. 1 H
c. 2 H
d. 2.5 H
2. If a carrier wave of 10MHz is amplitude modulated by an audio
signal of 1 kHz, the resultant signal to be broadcast contains only
the:
(A) 10,001,000-Hz component
(B) 10,001,000-Hz and 9,999,000-Hz components
(C) 10,001,000-Hz, 10,000,000-Hz, and 9,999,000-Hz...
help me please
please answer many as possible
10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iron core. C. using grain-oriented-steel D, reducing the connected load. 11. In Fig. 1(b) in the text, the phasor I, It is the resultant of the A. exciting and the magnetizing current. B. active and the reactive secondary current. C. primary and the exciting current. D....
2. A single-line diagram of the power system considered is shown in Figure P2a, where negative- and zero-sequence reactances are also given. The neutrals of the generator and A-Y transformers are solidly grounded. The motor neutral is grounded through a reactance Xn = 0.05 per unit on the motor base. The per-unit zero-, positive and negative-sequence networks on a 100-MVA is shown in Figure P26, 13.8-kV base in the zone of the generator. a. Reduce the sequence networks to their...
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