Questions
A three phase transformer of 400kVA, 10kV/400V, Dy11 is connected to its nominal load with cosφ...

A three phase transformer of 400kVA, 10kV/400V, Dy11 is connected to its nominal load with cosφ = 1.

a) Calculate the nominal primary and secondary line current.
b) Calculate the corresponding currents in the primary and secondary winding.

At an open circuit test, the primary line current is 0,52A with cosφ = 0,05 at nominal line voltage.
The short circuit test (at nominal current) shows 214V primary line voltage and P=1,333kW per phase.

c) Calculate the total iron losses and total copper losses of this transformer.

d) Calculate the efficiency η of this transformer.

Now the transformer will be loaded with 210kW with cosφ = 0,83 (lagging).

e) Give both the iron losses and the copper losses as a percentage of what they are nominally.

Please show process and computations with comments.

In: Electrical Engineering

1. 414 Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω...

1. 414 Volt, 60 Hz, 600 hp, 0.6 pf-leading, four-pole triangle connected synchronous motor has 0.9Ω synchronous reactance. Friction; wind; core losses and armature resistance are neglected.
a) If the motor is operating under magnitude of phase current (ia) 234 Ampere and power factor of 0.6 lagging,
1. Find the input power of motor in hp (10p)
2. Find the generated voltage, EA (10p)
3. Find the torque and the maximum inducible torque in current state. (10p)
b) If EA is increased by 18% find,
1. Magnitude of new armature current (ia), (10p)
2. New power factor of motor. (10p)
(X is the last two digits of your student number × 2. For example: If student number is 20-156-120, X=54. Motor voltage is found 360+(54*2) = 468V.)
(Please use at least 4 digits after decimal point in your calculations. Otherwise, there may be problems about exact answers.)

In: Electrical Engineering

Write a 3-4 paragraphs report about electric circuits submit it (why do we use circuits) typed...

Write a 3-4 paragraphs report about electric circuits submit it (why do we use circuits) typed please

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Design a Butterworth bandpass filter with the given requirements: 10 dB stopband attenuation at 100 rad/sec...

Design a Butterworth bandpass filter with the given requirements:

10 dB stopband attenuation at 100 rad/sec and 900 rad/sec

1dB passband attenuation at 400 rad/sec and 600 rad/sec

In: Electrical Engineering

A coaxial cable is made of two conductors, the inner one has radius a and the...

A coaxial cable is made of two conductors, the inner one has radius a and the outer radius is b, both conductors are seperated by a dielectric material with relative permitivity εr  and conductivity σ , what is the conductance per unit length of this insulating material. Show all steps you followed to obtain the final expression.

In: Electrical Engineering

Synchronous and Induction Machine Questions Q1: How do we find induced voltage, frequency, synchronous reactance, generated...

Synchronous and Induction Machine Questions

Q1: How do we find induced voltage, frequency, synchronous reactance, generated voltage at pf for a synchronous generator?

Q2: How do we find slip and number of poles, speed of rotor, load torque, induced torque in a induction motor?

Q3: Based on an induction motor test(no-load, blocked-rotor test)- what are the circuit parameters and how do we draw the circuit?

Q4: For a synchronous machine, how do we draw phasor diagram?

In: Electrical Engineering

The performance for a power factor of 1 of a 200KVA, 3000/380 V single phase transformer...

The performance for a power factor of 1 of a 200KVA, 3000/380 V single phase transformer is 0.98 for both full load and medium load. The vacuum power factor is 0.2 and the voltage drop at full load with a power factor of 0.8 is 4%. Determine the parameters of the equivalent circuit of the transformer referred to the primary side.

In: Electrical Engineering

1. What is the difference between a PNP and NPN transistor? 2. A transistor is an...

1. What is the difference between a PNP and NPN transistor?

2. A transistor is an element that amplifies current or voltage? Justify your answer

In: Electrical Engineering

Detect "010" using Moore state machine, overlapped, and minimized-bit state encoding. Use JK flip-flops. Shows your...

Detect "010" using Moore state machine, overlapped, and minimized-bit state encoding. Use JK flip-flops. Shows your state diagram, state table, encoded state table, logic equations, and logic circuit.

In: Electrical Engineering

Determine whether each system is LTI, causal and/or stable and with or without memory. Justify answers....

Determine whether each system is LTI, causal and/or stable and with or without memory. Justify answers.

a) y(t) =sen(x(t))

b) y(t) = dx/dt + x(t)

In: Electrical Engineering

For Four Quadrant chopper DC motor Drive: A. Explain the generator action in forward direction according...

For Four Quadrant chopper DC motor Drive:

A. Explain the generator action in forward direction according to:

1. Circuit

2. Waveforms

3. Principal of work


B. Is it possible to discharge the load current using D3D4 switching strategy. Explain?

In: Electrical Engineering

Consider GaAsP system. Determine the range of the direct bandgap energies possible and the corresponding range...

Consider GaAsP system. Determine the range of the direct bandgap energies possible and the corresponding range of wavelength.

In: Electrical Engineering

A three-phase line has an impedance of 1 + j2 Ω per phase. The line feeds...

A three-phase line has an impedance of 1 + j2 Ω per phase. The line feeds two balanced three-phase loads that are connected in parallel. The first load is Y-connected and has an impedance of 20+j40 Ω per phase. The second load is ∆-connected and has an impedance of 30-j60 Ω per phase. The line-to-line voltage at the load end of the line is 415V. Taking the phase voltage Va as reference, determine: a) The total current per phase from the source end .b) The magnitude of the line voltage at the source end of the line c) The total 3-phase real and reactive powers absorbed by each load . d) The total 3-phase real and reactive power losses in the line. e) The real power and reactive power supplied at the source end of the line. f) If the second load is now connected in Y-connection with the same impedance of 30-j60 Ω per phase, what would be the current per phase supplied by the source

In: Electrical Engineering

Q1:A high voltage Schering Bridge has the following arms with their component ranges: AB: capacitor=100 pF...


Q1:A high voltage Schering Bridge has the following arms with their component ranges: AB: capacitor=100 pF to 500 pF, BC: variable capacitance (1 nF to 2 µF) in parallel with variable resistance from (100 Ω to 1000 Ω), CD: variable resistance from (1 Ω to 1000 Ω), DA: test object. Determine:
(a) the maximum value of the capacitance of the bushing,

(b) the minimum value of the capacitance of the bushing

(c) the loss angle of the bushing if balance is obtained with capacitance of the bushing is 200pF, R4=1000Ω, C4=10nF with a high voltage capacitor having maximum value

(d) in this question, what is the difference between the bushing and the test object

In: Electrical Engineering

The secondary of a 500kVA, 4400/500 V, 50Hz, single-phase transformer has 500 turns. A) determine emf...

The secondary of a 500kVA, 4400/500 V, 50Hz, single-phase transformer has 500 turns.

A) determine emf per unit.

B) primary turns.

C) secondary full load current

D) maximum flux

E) gross cross-sectional area of the core for flux density of 1.2 tesla

F) if the core is square cross-section find the width of the limb

In: Electrical Engineering