The air preheater in a thermal power plant is called as

SSC JE Electrical 2018 with solution SET-1
The air preheater in a thermal power plant is called as

Starting Device

Safety Device

Very essential Device

Efficiency increasing equipment

Starting Device

Safety Device

Very essential Device

Efficiency increasing equipment

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SSC JE Electrical 2018 with solution SET-1
Calculate the induced emf (in V) in the inductor of a series RL circuit having the inductance of 1.8 H and resistance of 90 Ohms after 20 milli-seconds when supplied by a 20 V DC source

10.03

20

14.76

7.36

10.03

20

14.76

7.36

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SSC JE Electrical 2018 with solution SET-1
In a synchronous motor which loss varies with the load?

Core Loss

Copper Loss

Windage loss

Bearing friction Loss

Core Loss

Copper Loss

Windage loss

Bearing friction Loss

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SSC JE Electrical 2018 with solution SET-1
Which of the following is a static exciter?

DC Separately excited generator

Amplidyne

Rectifier

Metadyne

DC Separately excited generator

Amplidyne

Rectifier

Metadyne

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An AC or DC generator requires direct current to energize its magnetic field. The DC field current is obtained from a separate source called an exciter. Either rotating or static-type exciters are used for AC power generation systems. There are two types of rotating exciters: brush and brushless. The primary difference between brush and brushless exciters is the method used to transfer DC exciting current to the generator fields. Static excitation for the generator fields is provided in several forms including field-flash voltage from storage batteries and voltage from a system of solid-state components. DC generators are either separately excited or self-excited.
EXCITATION SYSTEMS in current use include direct-connected or gear-connected shaft-driven DC generators, belt-driven or separate prime mover or motor-driven DC generators, and DC supplied through static rectifiers.
Static Excitation System
As the name indicates, all the components in this type of excitation system are static. A set of rectifiers is fed from a transformer that steps down the main generator or auxiliary bus voltage. The rectifiers supply the main generator excitation current directly through slip rings and they may be controlled or uncontrolled.

An external source of DC is necessary for the initial excitation of the field windings. On engine-driven generators, the initial excitation may be obtained from the storage batteries used to start the engine or from control voltage at the switchgear.
The main advantage of the static exciter is improved response as the field current is controlled directly by the thyristor rectifier but, of course, if the generator terminal voltage is depressed too low then excitation power will be lost. It is again possible to provide the power supply from both voltage and current transformers at the generator terminals but it is doubtful whether the improved response of the static exciter over a permanent magnet brushless scheme can be justified for many small embedded generators.

SSC JE Electrical 2018 with solution SET-1
Which one of the following is a passive element to an electric circuit?

Resistors

Voltage source

Battery

Current source

Resistors

Voltage source

Battery

Current source

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SSC JE Electrical 2018 with solution SET-1
If the centrifugal switch does not open at 70 to 80 percent of a synchronous speed of the motor, it would result in

None of these

Damage to the starting winding

Overloading of running winding

Damage to the centrifugal switch

None of these

Damage to the starting winding

Overloading of running winding

Damage to the centrifugal switch

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SSC JE Electrical 2018 with solution SET-1

SSC JE Electrical 2018 with solution SET-1 The air preheater in a thermal power plant is called as

SSC JE Electrical 2018 with solution SET-1 Calculate the induced emf (in V) in the inductor of a series RL circuit having the inductance of 1.8 H and resistance of 90 Ohms after 20 milli-seconds when supplied by a 20 V DC source

SSC JE Electrical 2018 with solution SET-1 In a synchronous motor which loss varies with the load?

SSC JE Electrical 2018 with solution SET-1 Which of the following is a static exciter?

SSC JE Electrical 2018 with solution SET-1 Which one of the following is a passive element to an electric circuit?

SSC JE Electrical 2018 with solution SET-1 If the centrifugal switch does not open at 70 to 80 percent of a synchronous speed of the motor, it would result in

SSC JE Electrical 2018 with solution SET-1
The air preheater in a thermal power plant is called as

SSC JE Electrical 2018 with solution SET-1
Calculate the induced emf (in V) in the inductor of a series RL circuit having the inductance of 1.8 H and resistance of 90 Ohms after 20 milli-seconds when supplied by a 20 V DC source

SSC JE Electrical 2018 with solution SET-1
In a synchronous motor which loss varies with the load?

SSC JE Electrical 2018 with solution SET-1
Which of the following is a static exciter?

SSC JE Electrical 2018 with solution SET-1
Which one of the following is a passive element to an electric circuit?

SSC JE Electrical 2018 with solution SET-1
If the centrifugal switch does not open at 70 to 80 percent of a synchronous speed of the motor, it would result in