A plant consists of two 10 MVA generators of reactance 18% each and two 5 MVA generators of 12% each. All are connected to bus bar to supply a load through three step up transformers of 8 MVA each having reactance of 8%. Determine fault MVA on HV side of any one transformer.

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A three-phase transformer having a line voltage ratio of 0.4 kV/11kV is connected Star/Delta and protective transformers on the 0.4 kV side have a current ratio of 500/5. Calculate the ratio of the protective transformers on the 11 kV side. Draw a neat circuit diagram and indicate the given values at appropriate places.

A three-phase transformer having a line voltage ratio of 0.4 kV/11kV is connected Star/Delta and protective transformers on the 0.4 kV side have a current ratio of 500/5. Calculate the ratio of ... on the 11 kV side. Draw a neat circuit diagram and indicate the given values at appropriate places.

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A 3 phase line of 4 km length delivers 4000 kW at a p.f of 0.8 lagging to a load the resistance and reactance per km of each conductor are 0.2 Ω and 0.5 Ω respectively if the voltage at the supply end is maintained at 11 kV. Calculate the received end voltage and efficiency of line.
Answer : Let's break down the problem step by step and calculate the received end voltage and the efficiency of the line. ### Given Data: - Power delivered to the load, \( P = 4000 \, \text{kW} \) - Power factor, \( \text{p. ... voltage**: \( 10.43 \, \text{kV} \) - **Efficiency of the line**: \( 98.61\% \)...

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A 500kVA distribution transformer having copper and iron losses of 5kW and 3kW respectively on full load. The transformer is loaded as shown below: Loading (kW) Power Factor (Lag) No. of hours 400 0.8 06 300 0.75 12 100 0.8 03 No load - 03 Calculate the all-day efficiency.
Answer : To calculate the all-day efficiency of the transformer, we need to consider the total energy output, the total energy input, and the losses over a 24-hour period. The transformer experiences two types of ... \] ### Final Answer: The all-day efficiency of the transformer is approximately **98.39%**....

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A 220V/22kV three-phase transformer is connected in star/delta. The protective transformers on the 220V side have a current ratio of 400/5. Calculate the CT ratio on the 22kV side.

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A workshop measures 10m × 25m. The shop is illuminated by 24 lamps of 200 watts each. The lumen efficiency of each lamp is 15 lumens per watt. Depreciation factor is assumed to be 0.8 and a coefficient of utilization 0.5. Determine the illumination on the working plane.

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A motor has to exert power starting from zero and rising uniformly to 150 HP in 8 mins after which it works at constant power of 100 HP for 5 mins. The motor remains on no load for next 5 mins. The cycle again starts and repeats indefinitely. Determine suitable size of motor.

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What is the Q (Quality factor) of a series circuit that resonates at 10 kHz, has equal reactance of 5 kilo-ohms each, and a resistor value of 50 ohms?

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Explain the relation of V2 and I2 based on the load connected to the transformer.

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Explain with a neat circuit diagram only the Scott connection scheme for the conversion of three-phase supply to two-phase supply. Name one application of the same.

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Sketch a diagram showing interfacing of two chips of RAM having a size of 2k × 8 to the 8051 microcontroller. Write its memory map.

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There are a Transformer and an induction machine. Those two have the same supply. For which device the load current will be maximum? And why?

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Write any two differences between single-phase and three-phase transformers.

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Describe the method of converting a three-phase to a two-phase transformer by neat diagram. State any two applications.

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What are the key differences between a step-up and a step-down transformer?

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What is the difference between step-up and step-down transformers?

What is the difference between step-up and step-down transformers?
Answer : A **step-up transformer** and a **step-down transformer** are both types of electrical transformers, but they serve different purposes based on how they change voltage levels. ### Step-up Transformer - **Function* ... **, and if you need to **reduce** it, you use a **step-down transformer**....

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Why Power Plant Capacity Rated in MW and not in MVA?

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State any four advantages of having stationary armature in case of three phase alternator.

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What is theorem 8.5 Class 10?

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State the type of insulating materials under Class Y and Class B. (any two each).

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What is the difference between a step-up and step-down transformer?

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Two bulbs of 100w and 40w respectively connected in series across a 230v supply which bulb will glow bright and why?

Two bulbs of 100w and 40w respectively connected in series across a 230v supply which bulb will glow bright and why?
Answer : In this case, the two bulbs (100W and 40W) are connected in series across a 230V supply. To understand which bulb will glow brighter, we need to look at the power consumed by each bulb. ... voltage drop and thus dissipate more power, even if it is designed for lower power under normal conditions....

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What is the difference between the feeder and bus bar?

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What is the difference between isolators and –>electrical circuit breakers? What is bus-bar?

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What is the difference between isolators and electrical circuit breakers? What is bus-bar?

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What are different Bus bar materials used in Substation?

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List the speed control methods of three phase induction motor and explain any one method.

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Compare base load plant with peak load plant. (any four)

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List classification of distributor system with their advantages each. (any two)

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List any two direct methods of level measurement. Explain Hydrostatic method of level measurement. Give one advantage and one disadvantage of it.

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Describe the operation of a step-up transformer.

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Explain the working principle of a step-up transformer.

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How does a step-up transformer differ from a step-down transformer?

How does a step-up transformer differ from a step-down transformer?
Answer : A **step-up transformer** and a **step-down transformer** are both types of transformers that change the voltage of electricity, but they do so in opposite ways: 1. **Step-up ... induction, but their purpose is different depending on whether you need to increase or decrease the voltage....

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How does a step-up transformer work?

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How does a basic step-up transformer increase voltage?

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How does a basic transformer step up or step down voltage?

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Which meter has a greater sensitivity and why? Meter A having a range of 0-10 V and a multiplier resistance of 18 kΩ and meter B with a range of 0-300 V and multiplier resistance of 298 kΩ? Both meter movements have a resistance of 2 kΩ.

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A 3 φ I.M. has synchronous speed of 250rpm and 4% slip at full load. The rotor has a resistance of 0.02Ω/ph and stand still reactance of 0.15Ω/ph. Calculate i) The speed at which max torque is developed. ii) The ratio of maximum to F. L. torque. iii) The ratio of maximum to starting torque.

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What is the application of step-up transformer?

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List protection schemes used for the bus-bar.

List protection schemes used for the bus-bar.
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List different starting methods of three phase synchronous motor. Explain any one of them.

List different starting methods of three phase synchronous motor. Explain any one of them.
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Why the reactance of a system under fault condition is low and faults currents may raise dangerously high value. ? (With simple example)

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Are all motors generators?

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Draw the equivalent circuit of a transformer referred to the primary and state the meaning of each term related to the equivalent circuit.

Draw the equivalent circuit of a transformer referred to the primary and state the meaning of each term related to the equivalent circuit.
Answer : ### Equivalent Circuit of a Transformer Referred to the Primary Side The equivalent circuit of a transformer referred to the primary side is represented by an ideal transformer and various ... behavior like voltage drops, power losses, and efficiency based on the transformer's parameters....

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A uniform illumination of 150 lux is to be obtained on the floor of a room measuring 15m x 15m by arranging electric lights suitably. Calculate the number of lamps and wattage of each lamp if lamp efficiency is 20 lumens/watt. Assume and write suitable values of constants required for this calculation.

A uniform illumination of 150 lux is to be obtained on the floor of a room measuring 15m x 15m by arranging electric lights suitably. Calculate the number of lamps and wattage of each ... lamp efficiency is 20 lumens/watt. Assume and write suitable values of constants required for this calculation.

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