Single phase to ground fault is the most common type of fault.
What is the most common type of power plant?
Hydroelectric power plant.
To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?
To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection
Reactance relay is preferred for phase fault on short transmission line.
In which fault the maximum short circuit current occurs?
In three phase bolted fault the maximum short circuit occurs.
If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be
If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be 10
If the % reactance upto the fault point is 20%, then the short circuit current will be
If the % reactance upto the fault point is 20%, then the short circuit current will be 5 times the full load current
With fault clearing time, the transient stability of a power system
With fault clearing time, the transient stability of a power system decreases
The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.
Fault diverters are basically fast switches.
six most common multiples
six most common multiples
Draw full bridge & half bridge configuration with common cathode.
Half Bridge Configuration: Full Bridge Configuration:
Why common emitter configuration is commonly used?
Common emitter configuration is commonly used for amplifications because 1. The common emitter configuration (CE) provides maximum voltage and current gain and hence provides maximum power gain. The ... automatic impedance matching maximum power transfer will take place from one stage to other.
If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be A) 0.98 B) 0.41 C) 59 D) 55
If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be 0.98
The ac bypassing of RF by CF in a common emitter configuration : (A) increases ac signal across emitter -base junction (B) decreases ac signal across emitter -base junction (C) decreases voltage amplification (D) stabilizes the Q -point
The ac bypassing of RF by CF in a common emitter configuration : increases ac signal across emitter -base junction
Give the causes and impact and reasons of grid system fault.
Following are the causes/reasons grid system fault: 1. Major imbalance between generation and consumption i.e. demand is more than generation. 2. Low frequency, due to some faults the frequency ... of supply and causes inconvenience to people. 6. Disturb the routine work of common all people.
If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then (A) zero sequence currents are present on both sides of the transformer (B) zero sequence currents are absent on both sides of the transformer (C) zero sequence currents are present on the secondary side but not on the primary side (D) zero sequence currents are present on the primary side but not on the secondary side
If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then zero sequence currents are absent on both sides of the transformer
If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be
If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be 10 A
A shunt fault is characterized by (A) Increase in current, frequency and pf (B) Increase in current, reduction in frequency and pf (C) Increase in current and frequency, reduction in pf (D) Decrease in current and frequency
In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized
In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction
The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.
Sandwich type winding is used in 3 phase shell-type transformer.
Which type of starter is used to start the DC motor?
Which type of motor is used in lift?
Which type of heater is cheapest to run?
Transformer coupling introduces which type of distortion?
Transformer coupling introduces Cross over distortion.
Overload relays are of induction, solid state, thermal, electromagnetic type.
Explain working of a storage type water cooler with a sketch.
The storage type cooler has the evaporator coil soldered on to the walls of the storage tank of the cooler, generally on to the outside surface of the walls. The tank could be of the ... outside at a lower level, much below the lower most evaporator refrigerant tube soildered on to the tank.
State two applications of : (i) PVC paper (ii) Porcelain with type of class based on withstand temperature is insulating material.
(i) Application of PVC paper : 1. It is used in slot lining or motor winding insulation purpose 2. For Insulation of Transformer winding (ii) Application of Porcelain : 1. Mainly used for manufacturing ... on withstand temperature : * H' & C' Class of insulation i e. 180° and above 180°C
State the type of insulating materials under Class Y and Class B.
The type of insulating materials under Class Y : 1. Cotton 2. Silk 3. Paper 4. Rubber 5. PVC The type of insulating materials under Class B: 1. Backelite 2. Impregnated varnish 3. Mica 4. Fiber glass 5. Asbestos
State advantages of rotating field type alternators.
Advantages of Rotating Field Type Alternator: 1) For high-voltage alternator, large space is required to accommodate conductors with insulation, as high voltage is induced in them. If field poles are placed ... is kept rotating. 8) Rotating field is comparatively light and can run with high speed.
Compare Dual slope DVM and SAR type DVM.
Sr no Dual slope DVM SAR type DVM 1 It is highly accurate It is moderately accurate 2 Cost is high It is inexpensive 3 Two comparator is used One comparator is used ... resolution Good resolution 5 Slow speed High speed 6 Less Error More error
operation of ramp type DVM.
This is given to an input comparator which will compare two signals and generates the output. One input to the input comparator is from the input and another input is from the ramp. This input voltage and ... ground and output is given. This output will stop the flow of purchase from clock
operating principle of condenser type microphone with neat diagram.
Principle: When sound pressure moves the diapharam in, the capacitance increases, and when it moves out, the capacitance decreases. The change in capacitance results in change in out put voltage of microphone. ... in volts. Q= charge in coulombs C= capacitance in farad Diagram:
Describe the working principle of photoelectric pickup type tacho-generator.
Working: Working principle: The light passes through the holes available on the rotating disc with a specific interval, depends on the angular speed of disc having equidistant holes. The frequency of this light pulses ... by N=f/HS N=speed f=frequency Hs=holes on the disc
State the use of RADAR type level transducer & list two advantages.
Applications of radar type transducer: i) RADAR type level transducer is suitable for large tanks with range upto 200m for level measurement. ii) It is used for continuous level measurement. ... iii) Not affected by corrosive materials. iv) Can be used for hard to handle' applications.
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State any four characteristics of core type transformer.
Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.
With diagram explain bottoming cycle type of co-generation.
Bottoming cycle type of co-generation: i) Bottoming cycle of co-generation system is that in which high temperature heat energy is produced using primary fuels. ii) This heat produced is ... of the system greatly. vii) Bottoming cycles are suitable for cement industries, ceramic factories etc.
Describe principle of operation of Doppler type ultrasonic flow meter with diagram.
Diagram: Working: The flow meter consists of a crystal transducer mounted outside the pipe in which flow is to be measured. This transducer is a piezoelectric crystal which ... , so the frequency of the reflected wave is shifted to particle velocity, according to Doppler principle.
Draw the diagram and explain the working of ferrodynamic type frequency meter.
Ferrodynamic type frequency meter: (Electrical resonance type frequency meter): It consists of a fixed coil. The supply whose frequency is to be measured is connected across it. This coil ... so selected that the moving coil takes up a convenient position when frequency is of normal value.
Explain the essential toques in analog type measuring instruments.
List of torques in analog instruments: 1. Deflecting torque 2. Controlling / Restraining torque. 3. Damping torque. 1. Deflecting torque: To create deflection proportional to ... the speed higher will be the damping torque bringing the pointer to the equilibrium position quickly.
State the function and shape of following parts used in induction type energy meter: i) Series magnet ii) Shunt magnet iii) Al disc iv) Brake magnet
i) Series magnet: produce flux proportional to current (load current) of circuit and interact in the aluminum disc with flux produced by voltage magnet for torque production. Its shape is like letter U. ii) ... : brakes the motion of the aluminum disc or slows it down. Its shape is like letter C.
With neat sketch explain working of Weston type synchroscope.
Weston type synchroscope: Working: It consists of three limbed transformer. The winding on one of the outer limbs is excited from bus- bars and that on other limb by incoming machine. The two fluxes ... the lamp is flickering at a very much slow rate and it is at its maximum brightness.
State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.
Errors in wattmeter: i) pc - inductance: Pressure coil inductance causes wattmeter to read more power than actual . ii) pc-capacitance: The wattmeter reads less power. iii) ... iv) Connection: In uncompensated wattmeter , the reading of wattmeter includes the powerloss in coils.
With a neat sketch explain working of 1 phase dynamometer type power factor meter.
Working of 1 phase dynamometer type power factor meter : The current coil is connected in series with load. Two pressure coils marked as A and B are connected across the supply terminals ... becomes stationary and the pointer shows steady deflection corresponding to the power factor of the load.
Draw a neat sketch of 1-ph induction type energy meter and write operating principle of it.
Operating Principal:- The disc is placed between the two-flux due to pressure coil and flux due to current coil, which will set up torque on the disc which is proportional to power causing the ... is proportional to voltage, the second carries a current coil so its flux is proportional to current.
With neat diagram explain constructional details of dynamometer type wattmeter.
Working Principle of Wattmeter: It consists of two stationary coils, called current coils and one moving coil, called voltage or potential coil. The moving coil is mounted on the spindle, in the gap ... experiences a force and tends to move in the direction as per Fleming's left hand rule.
Explain construction & working of attraction type M.I. instrument with neat diagram.
1. Moving element: a small piece of soft iron in the form of a vane or rod. 2. In Attracted type a cylindrical coil or solenoid which is kept fixed. An oval-shaped soft-iron piece are ... 9. When = the pointer will be stable & we can get correct reading of the electrical quantity
Explain working of Weston type frequency meter.
Weston Type Frequency Meter: There are two fixed coils marked as A and B. Each coil divided into two equal parts and are fixed such that their magnetic axis are perpendicular to each ... leading to deflections in either direction depending on the currents there in, due to changed impedances.