The under voltage relay can be used for?

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1 Answer

Answer :

The under voltage relay can be used for generators, busbars, transformers, motors.

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Related questions

In order that current should flow without causing excessive heating or voltage drop, the relay contacts should?

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.

A relay used for protection of motors against overload is :

Description : 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

A negative sequence relay is used for protection of

Description : 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 

The purpose of the restraining coil in a biased differential relay is

Description : 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

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

Description : 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

The operating time of instantaneous relay is

Description : The operating time of instantaneous relay is

Last Answer : The operating time of instantaneous relay is 0.1 sec

What is the difference between relay and contactor?

Description : What is the difference between relay and contactor?

Last Answer : Relay have smaller ratings. Contactor is a high rating relay.

Buchholz relay is

Description : 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 

To prevent mal-operation of differentially connected relay while energizing a transformer, the relay

Description : 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 

Reactance relay is normally preferred for protection against

Description : Reactance relay is normally preferred for protection against

Last Answer : Reactance relay is normally preferred for protection against earth faults

In the induction type directional over current relay, when a short-circuit occurs in the circuit

Description : 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

A solid state relay

Description : 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

The torque produced in induction type relay (shaded pole structure) is?

Last Answer : The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.

Admittance relay is _______ relay.

Last Answer : Admittance relay is directional relay.

The relay with inverse time characteristic will operate within?

Last Answer : The relay with inverse time characteristic will operate within 5 to 10 sec.

Which relay is preferred for phase fault on short transmission line?

Last Answer : Reactance relay is preferred for phase fault on short transmission line.

Induction cup relay is operated due to changes in?

Last Answer : Induction cup relay is operated due to changes in current, voltage, impedance.

Interruption of large currents by relay requires?

Last Answer : Interruption of large currents by relay requires arc suppressing blow out coils, wide separation of the opened contacts, high speed opening of contacts.

Overheating of relay contacts or contact born out is due to?

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.

A differential relay measures the vector difference between?

Last Answer : A differential relay measures the vector difference between two or more similar electrical quantities.

Burden of a protective relay is the power?

Last Answer : Burden of a protective relay is the power absorbed by the circuit of relay.

The relay operating speed depends upon?

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

How do relay works ?

Description : How do relay works ?

Last Answer : Relay working like contact it is noise less 

What is the use of Buchholz relay in transformer?

Description : What is the use of Buchholz relay in transformer?

Last Answer : This is a transformer that is used to step up and down current. 

What is the difference between a switch and a relay?

Description : 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 .

State the type of insulating materials under Class Y and Class B.

Description : State the type of insulating materials under Class Y and Class B.

Last Answer : 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 

List standard voltage level used in India.

Description : List standard voltage level used in India. 

Last Answer : Standard voltage level used in India: * Generation Voltage : 3.3KV, 6.6KV,11KV and 17.5 KV,21KV (Now a days generation voltage is in the range of 11KV- 33KV) * Primary Transmission voltage :- 220 ... voltages in India are 765 KV (750KV), 400KV, 220KV, 132KV, 110KV, 66KV, 33KV, 22KV, 11KV.

An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic

Description : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be  (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field

Last Answer : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be either decreased or increased depending on the direction of the DC field

The frequencies and voltage used in Dielectric heating are

Description : The frequencies and voltage used in Dielectric heating are (A) 10 – 30 MHz, upto 25 kV (B) 50 – 60 Hz, upto 25 kV (C) 10 – 30 MHz, upto 100 V (D) 50 – 60 Hz, 110 V – 230 V

Last Answer : The frequencies and voltage used in Dielectric heating are 10 – 30 MHz, upto 25 kV

The voltage used for suburban trains in D.C. system is usually?

Last Answer : The voltage used for suburban trains in D.C. system is usually 600 to 750 V.

What equipment is used to measure voltage?

Description : What equipment is used to measure voltage?

Last Answer : Voltmeter is used to measure voltage.

Fuel Pump Relay

Description : 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.

main parts of Relay

Description : main parts of Relay

Last Answer : Coil, plunger, contacts, springs, connecting terminals and enclosure.

What is phase failure relay and how it's work?

Description : What is phase failure relay and how it's work?

Buchholz relay is used as a safety device with respect to which of the following?

Description : 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

A reactance relay is

Description : 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

A Buchholz relay can be installed on?

Last Answer : A Buchholz relay can be installed on oil cooled transformers.

Buchholz's relay gives warning and protection against?

Last Answer : Buchholz's relay gives warning and protection against electrical fault inside the transformer itself.

what is reverse power relay?

Description : 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!

The voltage of transmission can be regulated by

Description : The voltage of transmission can be regulated by  (A) Use of tap changing transformers (B) Switching in shunt capacitors at the receiving end during heavy loads (C) Use of capacitors to neutralize the effect of series reactance (D) Any of the above methods

Last Answer : The voltage of transmission can be regulated by  (A) Use of tap changing transformers (B) Switching in shunt capacitors at the receiving end during heavy loads (C) Use of capacitors to neutralize the effect of series reactance (D) Any of the above methods