What is voltage interruption?
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Mar 10, 2018
by
anonymous

Explain following techniques related to energy conservation in transmission and distribution system. (i) By balancing phase currents (ii) Variable technical losses (I2R losses).
Last Answer : (i) Balancing Phase currents: Proper (healthy balanced) three phase loads always draw equal currents in all lines but single phase loads in the 3 phase 4 wire system or loads connected between two ... . 11) Minimize I2R losses. 12) Balance the load currents. 13) Regulate the system voltages.
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Sep 22, 2018
by
anonymous
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The transient currents are associated with the?
Last Answer : The transient currents are associated with the changes in the stored energy in the inductors and capacitors.
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Mar 25, 2018
by
anonymous

Last Answer : In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.
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Mar 21, 2018
by
anonymous
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Last Answer : For handling greater currents induction wattmeters are used in conjunction with current transformers.
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Mar 21, 2018
by
anonymous

Eddy currents are induced in the pole shoes of a D.C. machine due to?
Last Answer : Eddy currents are induced in the pole shoes of a D.C. machine due to relative rotation between field and armature.
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Mar 20, 2018
by
anonymous

How eddy currents are generated?
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Mar 14, 2018
by
anonymous

The purpose of the restraining coil in a biased differential relay is (A) To reduce CT saturation during fault. (B) To increase the sensitivity of the relay. (C) To match the transformation ratio. (D) To limit the spill current through the relay during heavy external fault.
Last Answer : d
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May 8, 2018
by
anonymous

A relay used for protection of motors against overload is : (A) Impedance relay (B) Electromagnetic attraction type (C) Thermal relay (D) Buchholz's relay
Last Answer : D
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May 8, 2018
by
anonymous

A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is
Last Answer : A relay has a rating of 5 A, 2.2 sec IDMT and a relay setting of 125% TMS = 0.6. It is connected to a supply circuit through a C.T. 400/5 ratio. The fault current is 4000 A. The operating current of the relay is 6.25A
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May 3, 2018
by
anonymous

The operating time of instantaneous relay is
Last Answer : The operating time of instantaneous relay is 0.1 sec
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117 views
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May 3, 2018
by
anonymous

What is the difference between relay and contactor?
Last Answer : Relay have smaller ratings. Contactor is a high rating relay.
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May 2, 2018
by
anonymous

A negative sequence relay is used for protection of (1) Generator (3) Motor (2) Transformer (4) Long Transmission lines
Last Answer : A negative sequence relay is used for protection of Generator
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May 1, 2018
by
anonymous
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Buchholz relay is (1) located in the conservator tank (2) located in the transformer tank itself (3) connected in the pipe connecting main tank of transformer and conservator (4) installed in the circuit breaker
Last Answer : Buchholz relay is connected in the pipe connecting main tank of transformer and conservator
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Apr 30, 2018
by
anonymous
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To prevent mal-operation of differentially connected relay while energizing a transformer, the relay restraining coil is based with (1) second harmonic current (2) third harmonic current (3) fifth harmonic current (4) seventh harmonic current
Last Answer : To prevent mal-operation of differentially connected relay while energizing a transformer, the relay restraining coil is based with second harmonic current
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Apr 29, 2018
by
anonymous

Reactance relay is normally preferred for protection against
Last Answer : Reactance relay is normally preferred for protection against earth faults
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Apr 29, 2018
by
anonymous

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
Last Answer : In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction
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Apr 28, 2018
by
anonymous

A solid state relay (A) withstands voltage transients (B) does not require auxiliary dc supply (C) provide low burden on CT and P (D) does not provide earth fault protection
Last Answer : A solid state relay provide low burden on CT and P
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Apr 28, 2018
by
anonymous

Last Answer : The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.
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Mar 20, 2018
by
anonymous
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Last Answer : Admittance relay is directional relay.
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Mar 20, 2018
by
anonymous

Last Answer : The relay with inverse time characteristic will operate within 5 to 10 sec.
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Mar 20, 2018
by
anonymous

Last Answer : The under voltage relay can be used for generators, busbars, transformers, motors.
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Mar 20, 2018
by
anonymous

Last Answer : Reactance relay is preferred for phase fault on short transmission line.
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Mar 20, 2018
by
anonymous

Last Answer : Induction cup relay is operated due to changes in current, voltage, impedance.
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Mar 20, 2018
by
anonymous

Last Answer : Overheating of relay contacts or contact born out is due to slow making and breaking of load circuit contacts, foreign matter on the contact surface, too low contact pressure.
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1 answer
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Mar 20, 2018
by
anonymous

Last Answer : A differential relay measures the vector difference between two or more similar electrical quantities.
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Mar 19, 2018
by
anonymous

Last Answer : Burden of a protective relay is the power absorbed by the circuit of relay.
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Mar 19, 2018
by
anonymous

Last Answer : In order that current should flow without causing excessive heating or voltage drop, the relay contacts should have low contact resistance, be clean and smooth, be of sufficient size and proper shape.
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1 answer
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Mar 19, 2018
by
anonymous

Last Answer : The relay operating speed depends upon the spring tension, the rate of flux built up, armature core air gap.
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Mar 19, 2018
by
anonymous

How do relay works ?
Last Answer : Relay working like contact it is noise less
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Dec 30, 2017
by
anonymous

What is the use of Buchholz relay in transformer?
Last Answer : This is a transformer that is used to step up and down current.
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Dec 17, 2017
by
anonymous

What is the difference between a switch and a relay?
Last Answer : Switch is simply a mechanical contact mechanism and relay is a electromagnetic switch . Switch can be direct mechanically turn on and off but relay can be operated by energising coil .
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Dec 17, 2017
by
anonymous

Interruption of large currents by relay requires (a) arc suppressing blow out coils (b) wide separation of the opened contacts (c) high speed opening of contacts (d) all of the above
Last Answer : (d) all of the above
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1 answer

How to Shrink Large Pores
Last Answer : How to Shrink Large Pores Large pores can be a hassle, especially in a world full of airbrushed models with no visible pores filling our magazine pages. Large pores can also lead to a tendency ... add calamine or sandalwood powder to the tomato juice before applying. Rinse it off with warm water.
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A large AC generator, supplying power to an infinite bus, has a sudden short-circuit occurring at its terminals. Assuming the prime mover input and the voltage behind the transient reactance to remain constant immediately after the fault, acceleration of the generator rotor is
Last Answer : A large AC generator, supplying power to an infinite bus, has a sudden short-circuit occurring at its terminals. Assuming the prime mover input and the voltage behind the transient reactance ... , acceleration of the generator rotor is inversely proportional to the moment of inertia of the machine
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asked
Apr 29, 2018
by
anonymous
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Last Answer : A sensitive galvanometer produces large deflection for a small value of current.
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Mar 21, 2018
by
anonymous

Last Answer : Large capacity generators are invariably hydrogen cooled.
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Mar 20, 2018
by
anonymous

Fuel Pump Relay
Last Answer : Some car owners immediately suspect a fuel pump failure when their cars stall. However, there are many other engine problems that may resemble a fuel pump failure, such as restricted fuel filters, smashed ... advisable to bring your car to the repair shop so that the whole engine can be checked.
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1 answer
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May 5, 2021
by
anonymous

main parts of Relay
Last Answer : Coil, plunger, contacts, springs, connecting terminals and enclosure.
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Aug 28, 2019
by
anonymous

What is phase failure relay and how it's work?
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Aug 12, 2019
by
anonymous

Buchholz relay is used as a safety device with respect to which of the following? A) Audio transformers B) Oil filled power transformers C) Air core transformer D) None of these
Last Answer : Buchholz relay is used as a safety device with respect to which of the following? A) Audio transformers B) Oil filled power transformers C) Air core transformer D) None of these
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Apr 29, 2018
by
anonymous

A reactance relay is (A) Voltage restrained directional relay (B) Directional restrained over-current relay (C) Voltage restrained over current relay (D) Directional restrained over voltage relay
Last Answer : A reactance relay is Directional restrained over-current relay
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asked
Apr 28, 2018
by
anonymous

Last Answer : A Buchholz relay can be installed on oil cooled transformers.
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Mar 19, 2018
by
anonymous

Last Answer : Buchholz's relay gives warning and protection against electrical fault inside the transformer itself.
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108 views
1 answer
asked
Mar 19, 2018
by
anonymous

what is reverse power relay?
Last Answer : Thereverse powerrelay is a directional protective relay that prevents power from flowing in the reverse direction. Read our article going back ... it all to be up to date. And if you do, read it anyway just to check if youreallydo!
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asked
Dec 4, 2017
by
anonymous

Calculate the current if 12 coulombs of charge passes through a wire at a steady rate in 35 seconds
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Jun 3, 2021
by
barry
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The current zero interruption, in oil and air blast circuit breakers, is achieved by?
Last Answer : The current zero interruption, in oil and air blast circuit breakers, is achieved by lengthening of the gap, cooling and blast effect.
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asked
Mar 19, 2018
by
anonymous
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A differential relay measures the vector difference between (a) two currents (b) two voltages (c) two or more similar electrical quantities (d) none of the above
Last Answer : (c) two or more similar electrical quantities
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1 answer

With the help of neat diagram, explain operation of static relay.
Last Answer : Operation of Static Relay: Operation: 1) The solid-state component used are transistors, diodes, resistors, IC s, capacitor etc. The function of comparison and measurement are accomplished by ... ) An auxiliary dc supply is provided for operation of static relay elements as shown in figure.
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Jun 23, 2020
by
anonymous
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Describe the construction and Operation of Buchholz relay with neat labeled diagram.
Last Answer : Construction of Buchholz Relay: It takes the form of a domed vessel placed in the connecting pipe between the main tank and the conservator. The device has two elements. The upper element ... manner that it senses the sudden violent movement of oil/gas from transformer tank to conservator.
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1 answer
asked
Jun 23, 2020
by
anonymous
