menu search
person
How do relay works ?
thumb_up_alt 2 like thumb_down_alt 0 dislike
111 views

1 Answer

Relay working like contact it is noise less 


thumb_up_alt 1 like thumb_down_alt 0 dislike
← Prev Question Next Question →

Related questions

Description :

Explain in brief how anti-lock braking system works

Answer :

An ABS is a system on motor vehicles which prevents the wheels from locking while braking stopping safely is one of the most important functions a motor vehicle can perform. Diagram: ... to decrease the pressure on the braking circuit, effectively reducing the braking force on that wheel.

thumb_up_alt 0 like thumb_down_alt 0 dislike
55 views 1 answer
Description :

How does an electric motor works?

Answer :

In the electric motor there are two types of part 1)moving and 2)stationary In stationary part containing field winding whis use to provide uniform maganetic field it at inner side of yoke In moving ... on it and this force is from all direction we can say it is torque.and motor armature rotates

thumb_up_alt 3 like thumb_down_alt 0 dislike
110 views 1 answer
Description :

The transformer works on the principle of: (A) Mutual induction (B) Mutual capacitance (C) All of the above (D) None of the above

Answer :

The transformer works on the principle of:  Mutual induction

thumb_up_alt 0 like thumb_down_alt 0 dislike
73 views 1 answer
Description :

Answer :

A hysteresis motor works on the principle of hysteresis loss.

thumb_up_alt 0 like thumb_down_alt 0 dislike
94 views 1 answer
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.

Answer :

d

thumb_up_alt 0 like thumb_down_alt 0 dislike
578 views 2 answers
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

Answer :

A relay used for protection of motors against overload is : Thermal relay

thumb_up_alt 0 like thumb_down_alt 0 dislike
311 views 1 answer
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

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
494 views 1 answer
Description :

The operating time of instantaneous relay is

Answer :

The operating time of instantaneous relay is 0.1 sec

thumb_up_alt 0 like thumb_down_alt 0 dislike
105 views 1 answer
Description :

What is the difference between relay and contactor?

Answer :

Relay have smaller ratings. Contactor is a high rating relay.

thumb_up_alt 0 like thumb_down_alt 0 dislike
5.1k views 1 answer
Description :

A negative sequence relay is used for protection of  (1) Generator (3) Motor (2) Transformer (4) Long Transmission lines

Answer :

A negative sequence relay is used for protection of Generator 

thumb_up_alt 0 like thumb_down_alt 0 dislike
592 views 1 answer
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

Answer :

Buchholz relay is connected in the pipe connecting main tank of transformer and conservator 

thumb_up_alt 0 like thumb_down_alt 0 dislike
68 views 1 answer
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

Answer :

To prevent mal-operation of differentially connected relay while energizing a transformer, the relay restraining coil is based with  second harmonic current 

thumb_up_alt 0 like thumb_down_alt 0 dislike
277 views 1 answer
Description :

Reactance relay is normally preferred for protection against

Answer :

Reactance relay is normally preferred for protection against earth faults

thumb_up_alt 0 like thumb_down_alt 0 dislike
90 views 1 answer
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

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
91 views 1 answer
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

Answer :

A solid state relay provide low burden on CT and P

thumb_up_alt 0 like thumb_down_alt 0 dislike
50 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
725 views 1 answer
Description :

Answer :

Admittance relay is directional relay.

thumb_up_alt 0 like thumb_down_alt 0 dislike
136 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
96 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
55 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
98 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
286 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
72 views 1 answer
Description :

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.

thumb_up_alt 0 like thumb_down_alt 0 dislike
101 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
132 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
741 views 1 answer
Description :

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.

thumb_up_alt 0 like thumb_down_alt 0 dislike
119 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
227 views 1 answer
Description :

What is the use of Buchholz relay in transformer?

Answer :

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

thumb_up_alt 1 like thumb_down_alt 0 dislike
133 views 1 answer
Description :

What is the difference between a switch and a relay?

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 .

thumb_up_alt 0 like thumb_down_alt 0 dislike
100 views 1 answer
Description :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
53 views 0 answers
Description :

main parts of Relay

Answer :

Coil, plunger, contacts, springs, connecting terminals and enclosure.

thumb_up_alt 0 like thumb_down_alt 0 dislike
58 views 1 answer
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

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
86 views 1 answer
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

Answer :

A reactance relay is Directional restrained over-current relay

thumb_up_alt 0 like thumb_down_alt 0 dislike
87 views 1 answer
Description :

Answer :

A Buchholz relay can be installed on oil cooled transformers.

thumb_up_alt 0 like thumb_down_alt 0 dislike
58 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
79 views 1 answer
Description :

what is reverse power relay?

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!

thumb_up_alt 0 like thumb_down_alt 0 dislike
51 views 1 answer
Description :

Pranesh can do a piece of job in 60 days. He works at it for 4 days and then sarvesh alone finishes the remaining work in28 days. In how much time will pranesh and sarvesh working together, finish the work? a) 35 days b) 30 days c) 25 days d) 20 days

Answer :

D Work done by pranesh in 4 days = 1/60 *4 =1/15 Remaining work = 1-1/15 =(15 - 1)/15 =14/15 Now 14/15 work done by sarvesh in 28 days Whole work will be done by sarvesh in(28*15 /14) = 2* 15 =30 ... 's work = 1/60 + 1/30 = (1+2) /60 = 3/60 =1/20 Hence both will finish the work in 20 days

thumb_up_alt 0 like thumb_down_alt 0 dislike
33 views 1 answer
Description :

6 boys and 5girls can do a job in 8 days. When 7 boys and 10 girls work on the same job, the work gets completed in 5 days. How many days will a boy take to do the job, if he works alone on it? a) A.25 b) B.50 c) C.75 d) D.100

Answer :

D Let the amount of work done by a boy in a day be B′ and the amount of work done by a girl in a day be G′. Therefore, 6 boys and 5 girls will do 6B+5G amount of work in a day. If 6 boys and 5 ... 1/100 i.e. a boy does 1/100th of the work in a day. Hence he will take 100 days to do the work.

thumb_up_alt 0 like thumb_down_alt 0 dislike
20 views 1 answer
Description :

Earth Leakage circuit breaker (ELCB) works on the basis of

Answer :

Earth Leakage circuit breaker (ELCB) works on the basis of Residual current

thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
Description :

With the help of neat diagram, explain operation of static relay.

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.

thumb_up_alt 0 like thumb_down_alt 0 dislike
32 views 1 answer
Description :

Describe the construction and Operation of Buchholz relay with neat labeled diagram.

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. 

thumb_up_alt 0 like thumb_down_alt 0 dislike
83 views 1 answer
Description :

Describe the operation of current differential relay with neat sketch.

Answer :

Operation of Current Differential Relay: Figure shows an arrangement of an overcurrent relay connected to operate as a differential relay for alternator protection under fault conditon. ... current flows through relay coil, causing relay to operate for protection of alternator winding.

thumb_up_alt 0 like thumb_down_alt 0 dislike
58 views 1 answer
Description :

With a neat sketch, explain the working of Thermal relay.

Answer :

Working of Thermal Relay: 1) When the system is in normal operating condition, the heating element carries normal current from CT, this current produces heat = I2Rt. This heat ... of the spring releases which operates relay contacts resulting into providing trip signal to trip circuit.

thumb_up_alt 0 like thumb_down_alt 0 dislike
37 views 1 answer
Description :

Define the following terms with respect to protective relays i) Relay time ii) Reset current iii) Plug setting multiplier and iv) Time setting multiplier

Answer :

1) Relay Time: The time interval between occurrence of fault and closure of relay contacts.  2) Reset Current: The value of current below which the relay resets and comes back to ... The adjustment arrangement provided for setting the operation time of relay is known as Time setting multiplier. 

thumb_up_alt 0 like thumb_down_alt 0 dislike
52 views 1 answer
Description :

Draw a typical time-current characteristic for IDMT relay. 

Answer :

Time-Current Characteristic for IDMT Relay:

thumb_up_alt 0 like thumb_down_alt 0 dislike
85 views 1 answer
Description :

Explain operation of balanced beam type relay.

Answer :

Balanced Beam Type Relay: Under normal operating condition the current through relay coil is such that the beam is held in the horizontal position by the spring. When the fault occurs on the system the ... becomes greater than pick-up value and beam is attracted to close the trip circuit. 

thumb_up_alt 0 like thumb_down_alt 0 dislike
62 views 1 answer
Description :

Explain Buchholz relay with neat labelled diagram.

Answer :

Buchholz relay: The relay is located in the path of the oil from transformer tank to conservator. As seen from diagram, the upper mercury switch operates the alarm circuit due to tilting of the ... manner that it senses the sudden violent movement of oil from transformer tank to conservator.

thumb_up_alt 0 like thumb_down_alt 0 dislike
381 views 1 answer
Description :

Explain MHO relay in detail.

Answer :

MHO Relay: In this relay, poles 1, 2, 3 are energized by a voltage V through polarizing coil to produce flux, the capacitor connected provides phase shift. The left pole 4 is energized by a current which is the ... hence on the ratio (I/V) = Y i.e. admittance, hence called as MHO relay.

thumb_up_alt 0 like thumb_down_alt 0 dislike
2.5k views 1 answer
Description :

Describe over current relay with time-current characteristic.

Answer :

Over current relay with time-current characteristics:- 1. Definite time over current relay: Operating time is constant, the relays operates after a predetermined time when the current exceeds the pickup ... of fault current and definite time characteristics at higher values of fault current.

thumb_up_alt 0 like thumb_down_alt 0 dislike
257 views 1 answer
Description :

Explain operation of µP based relay with block diagram

Answer :

Operation of Microprocessor (µP) based relay: The inputs from the power system through CTs and PTS are received by the analog Input receiver; they are sampled simultaneously or ... compares the dynamic inputs and decides accordingly to generate trip/alarm signal to the output device.

thumb_up_alt 0 like thumb_down_alt 0 dislike
103 views 1 answer
editAsk a Question
...