In a static over-current relay, inverse time characteristics are obtained by

In a static over-current relay, inverse time characteristics are obtained by 

 (a) A differentiating circuit (b) An integrating circuit (c) A transistor amplifier (d) A transistor switch
by

1 Answer

Answer :

B
by

Related questions

What is the characteristic of inverse time over current relay?

Description : What is the characteristic of inverse time over current relay?  

Last Answer : If the fault current increases the time of the operation of the relay will be decreases.  

Inverse definite minimum time lag relay is also called ___________ (A) pilot relay. (B) differential relay. (C) over current relay. (D) directional overcurrent relay.

Description : Inverse definite minimum time lag relay is also called ___________ (A) pilot relay. (B) differential relay. (C) over current relay. (D) directional overcurrent relay.

Last Answer : Ans: B Inverse definite minimum time lag relay characteristic is inverse but minimum time is fixed. The operating time is inversely proportional to the magnitude of actuating quantity.

Purpose of Directional inverse Over current & earth fault relay; type- CDD

Description : Purpose of Directional inverse Over current & earth fault relay; type- CDD

Last Answer : Directional phase or earth fault protection of ring-mains, parallel transformers, transformer feeders, parallel feeders etc., employing the time graded principle.; This relay comprises an inductive ... induction disc unit. The directional unit is normally provided with voltage polarising coils. 

Purpose of over current relay (Inverse); type- CDG

Description : Purpose of over current relay (Inverse); type- CDG  

Last Answer : It is a self powered inverse time over current and earth fault relay, used for selective phase and earth fault protection in time graded systems for A.C. machines, transformers, feeders ... it rotates the driving torque increases and offsets the changing restraining torque of the control spring. 

The relay with inverse time characteristic will operate within (a) 1.5 sec (b) 5 to 10 sec (c) 5 to 20 sec (d) 20 to 30 sec (e) none of the above

Description : The relay with inverse time characteristic will operate within (a) 1.5 sec (b) 5 to 10 sec (c) 5 to 20 sec (d) 20 to 30 sec (e) none of the above

Last Answer : (b) 5 to 10 sec

The relay with inverse time characteristic will operate within?

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

What are the advantages of static relay over electromagnetic relay?

Description : What are the advantages of static relay over electromagnetic relay?

Last Answer : o Low power consumption as low as 1mW o No moving contacts; hence associated problems of arcing, contact bounce, erosion, replacement of contacts o No gravity effect on operation of ... testing and servicing. Can convert even non-electrical quantities to electrical in conjunction with transducers.

Rankine's deflection angle in minutes is obtained by multiplying the length of the chord by (A) Degree of the curve (B) Square of the degree of the curve (C) Inverse of the degree of the curve (D) None of these

Description : Rankine's deflection angle in minutes is obtained by multiplying the length of the chord by (A) Degree of the curve (B) Square of the degree of the curve (C) Inverse of the degree of the curve (D) None of these

Last Answer : (A) Degree of the curve

The torque-speed characteristics of an a.c. operated universal motor has a ______characteristic and it______ be started under no-load condition. (A) inverse, can (B) nearly inverse, can (C) inverse, cannot (D) nearly inverse, cannot

Description : The torque-speed characteristics of an a.c. operated universal motor has a ______characteristic and it______ be started under no-load condition. (A) inverse, can (B) nearly inverse, can (C) inverse, cannot (D) nearly inverse, cannot

Last Answer : Ans: C If torque is zero then speed may exceed up to infinite, that is dangerous for machine and machine can be damaged. N α 1/ T

The inverse definite mean time relays are used for over current and earth fault protection of transformer against (a) heavy loads (b) internal short-circuits (c) external short-circuits (d) all of the above

Description : The inverse definite mean time relays are used for over current and earth fault protection of transformer against (a) heavy loads (b) internal short-circuits (c) external short-circuits (d) all of the above

Last Answer : (b) internal short-circuits

The inverse definite mean time relays are used for over current and earth fault protection of transformer against?

Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.

The operating characteristics of a reactance type distance relay (A) a stepped waveform for increasing

Description : The operating characteristics of a reactance type distance relay (A) a stepped waveform for increasing reactance (B) a straight line for a constant reactance (C) a circle for a constant reactance (D) a set of circles for variable reactances

Last Answer : The operating characteristics of a reactance type distance relay a straight line for a constant reactance

What is static relay?

Description : What is static relay?

Last Answer : It is a relay in which measurement or comparison of electrical quantities is made in a static network which is designed to give an output signal when a threshold condition is passed which operates a tripping device.

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

Description : 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.

A series resistance is added to the over-current relay in a bus bar differential protection scheme which:

Description : A series resistance is added to the over-current relay in a bus bar differential protection scheme which: a. Helps to develop some voltage across it which otherwise should appear across the relay and is ... the effects of CT saturation and lowers the pickup value of the relay d. All of the above 

Last Answer : A series resistance is added to the over-current relay in a bus bar differential protection scheme which: a. Helps to develop some voltage across it which otherwise should appear across the relay and is ... the effects of CT saturation and lowers the pickup value of the relay d. All of the above 

In induction type directional over current relay the driving torque is due to interaction of magnetic fields

Description : In induction type directional over current relay the driving torque is due to interaction of magnetic fields derived from (A) current in the potential coil (B) both voltage and current in the ... (C) directional element and non-directional element (D) non-directional element and the trip circuit

Last Answer : In induction type directional over current relay the driving torque is due to interaction of magnetic fields derived from directional element and non-directional element

State the static and dynamic characteristics of instruments.

Description : State the static and dynamic characteristics of instruments. 

Last Answer : Static characteristics: i. Accuracy ii. Sensitivity iii. Reproducibility iv. Drift v.Static error vi. Dead zone vii. Repeatability viii. Precision ix Linearity  Dynamic characteristics: i. Speed of response ii. Measuring lag iii. Fidelity iv. Dynamic error

The operating torque of the upper induction disc-type element, or timer element, of an AC reverse power relay is obtained from ____________. A. the main bus B. a separate battery source C. line voltage D. electromagnets

Description : The operating torque of the upper induction disc-type element, or timer element, of an AC reverse power relay is obtained from ____________. A. the main bus B. a separate battery source C. line voltage D. electromagnets

Last Answer : Answer: D

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Description : Ratio of voltages is inverse ratio of the A. transformer B. resistor C. iron core D. current

Last Answer : current

Consider the following statements: (a) Revised simplex method requires lesser computations than the simplex method. (b) Revised simplex method automatically generates the inverse of the current basis matrix. (c) Less number of entries are needed in each table of revised simplex method than usual simplex method. Which of these statements are correct? (A) (a) and (b) only (B) (a) and (c) only (C) (b) and (c) only (D) (a), (b) and (c)

Description : Consider the following statements: (a) Revised simplex method requires lesser computations than the simplex method. (b) Revised simplex method automatically generates the inverse of the current basis matrix. (c) Less number of entries are needed ... c) only (C) (b) and (c) only (D) (a), (b) and (c)

Last Answer : (D) (a), (b) and (c)

For a traction transformer circuit breaker state: 1) Rated current and rupturing capacity 2) Any two tests it should be capable of withstanding 3) Overall tripping time and relay time.

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Last Answer : Ans: 1) Rated current --- 750 A and Rupturing capacity --- 500 MVA  2) Any two tests it should be capable of withstanding --- Breaking test , Reclosing test , Endurance test ( any two )  3) Overall tripping time --- 0.14 sec and Relay time --- 0.04 sec 

An inverse transducer converts

Description : An inverse transducer converts   (a) electrical energy to any other form of energy (b) electrical energy to light energy (c) mechanical displacement into electrical signal (d) electrical energy to mechanical form  

Last Answer : A

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Description : What is the inverse of reactance?

Last Answer : Inverse of reactance is Susceptance .Unit of Susceptance is Siemens.

Low voltage releases as used in some shipboard motor starter and control equipment will have which of the following characteristics? A. They trip circuit contactors when the motor starts to overspeed. B. They require manual resetting upon restoration of normal voltage. C. They use a phase sensitive relay to trip contacts in series with the holding coil of the starter. D. They allow the motor to restart upon restoration of normal voltage.

Description : Low voltage releases as used in some shipboard motor starter and control equipment will have which of the following characteristics? A. They trip circuit contactors when the motor starts to overspeed. B. ... coil of the starter. D. They allow the motor to restart upon restoration of normal voltage.

Last Answer : Answer: D

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Description : Explain the principle of operation of attracted armature relay with equation and characteristics curve.

Last Answer : Principle: It works on the principle that when a current is passed through a coil magnetic lines of force develop and the coil behaves like a magnet. When we place a magnetic material inside the coil it is ... ) time delay. If we want a time delay we can add a slug in the armature core.  

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Last Answer : (B) Pitot tube

………………….. implies that all subnets obtained from the same subnet mask. A) Static subnetting B) Dynamic subnetting C) Variable length subnetting D) Both B and C

Description : ………………….. implies that all subnets obtained from the same subnet mask. A) Static subnetting B) Dynamic subnetting C) Variable length subnetting D) Both B and C

Last Answer : A) Static subnetting

........ implies that all subnets obtained from the same network use the subnet mask. A) Static subnetting B) Dynamic Subnetting C) Variable length subnetting D) Both B and C

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Last Answer : A) Static subnetting

Describe over current relay with time-current characteristic.

Description : Describe over current relay with time-current characteristic.

Last 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.

What is the difference between over voltage relay and over current relay?

Description : What is the difference between over voltage relay and over current relay?

Last Answer : A:The current increases not only for over voltages but also for under voltage(As most of the loads are non-linear in nature). So,the over voltage protection & over current protection are completely ... , for a better protection of the system.It should have both over voltage & over current relay.

When voltage increases then current also increases then what is the need of over voltage relay and over current relay? Can we measure over voltage and over current by measuring current only?

Description : When voltage increases then current also increases then what is the need of over voltage relay and over current relay? Can we measure over voltage and over current by measuring current only?

Last Answer : No. We can't sense the over voltage by just measuring the current only because the current increases not only for over voltages but also for under voltage (As most of the loads are non-linear in ... So, for a better protection of the system. It should have both over voltage & over current relay.

What is the advantage of CMM relay over normal Inv. O/C current relay?

Description : What is the advantage of CMM relay over normal Inv. O/C current relay?

Last Answer : Inv. O/C relay under protects at low current and over protects at high currents. CMM: accounts for both +ve and -ve sequence currents i.e. Single phasing / unbalance supply conditions ... closely matched to motor heating characteristic. So it is better than thermal overload relay also. 

Why IDMT over current relay is always used as backup?

Description : Why IDMT over current relay is always used as backup?

Last Answer : Because setting has to be 200% to emergency loading and TMS be large to grade with feeder. Therefore very slow for internal faults/terminal faults/uncleared LV faults. 

Purpose of Over current & earth fault relay; type- CAG

Description : Purpose of Over current & earth fault relay; type- CAG  

Last Answer : This relays are designed for instantaneous phase or earth fault protection and instantaneous high set over current protection.; A standard hinged-armature unit forms the basic movement for this relay. It consists an ... to the end of the core while the other arm to operate a set of contacts.  

When voltage increases then current also increases then why we need of over voltage relay and over current relay? Can we measure over voltage and over current by measuring current only?

Description : When voltage increases then current also increases then why we need of over voltage relay and over current relay? Can we measure over voltage and over current by measuring current only?

Last Answer : No. We cannot sense the over voltage by just measuring the current only because the current increases not only for over voltages but also for under voltage (As most of the loads are non-linear in ... , for a better protection of the system. It should have both over voltage & over current relay.

Explain construction and operation of induction type directional over current relay.

Description : Explain construction and operation of induction type directional over current relay.

Last Answer : Directional overcurrent relay: Construction: It consists of two units: i) Non-directional Over-current unit ii) Directional power unit The directional unit consists of upper electromagnet ... closes the trip circuit. This operates circuit breaker which isolates the faulty section. 

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

Draw V-I characteristics of p-n junction diode? Define static and dynamic resistance of diode.

Description : Draw V-I characteristics of p-n junction diode? Define static and dynamic resistance of diode.

Last Answer : Static Resistance: The resistance offered by a p-n junction diode when it is connected to a DC circuit is called static resistance.  (OR) It is the ratio of DC voltage applied across diode ... The dynamic resistance of a diode is the ratio of change in voltage to the change in current. 

List characteristics of static data member and static member function.

Description : List characteristics of static data member and static member function.

Last Answer : Characteristics of static member variable are: i) It is initialized to zero when the first object of its class is created. No other initialization is permitted. ii) Only one copy of that ... the class name with a scope resolution operator instead of object name as follows: class_name::function_name;

Define the static characteristics: i) Resolution ii) Drift.

Description : Define the static characteristics: i) Resolution ii) Drift.

Last Answer : i) Resolution: It is the smallest increment in the input which can be detected by the instrument or the smallest measurable input change.  ii) Drift: The gradual shift in the indication or record of ... of time, during which the true value of the variable does not change is referred to as drift. 

In measurement system, which of the following static characteristics is desirable ?

Description :  In measurement system, which of the following static characteristics is desirable ? a) accuracy b) sensitivity c) reproducibility d) all the above

Last Answer : d) all of the above

The desirable static characteristics of a measuring system are?

Last Answer : The desirable static characteristics of a measuring system are accuracy, sensitivity and reproducibility.

A radioactive isotope undergoes decay with respect to time following __________ law. (A) Logarithmic (B) Exponential (C) Linear (D) Inverse square

Description : A radioactive isotope undergoes decay with respect to time following __________ law. (A) Logarithmic (B) Exponential (C) Linear (D) Inverse square

Last Answer : (B) Exponential

With which of the following, a circuit breaker must be equipped for remote operation ? (a) Inverse time trip (b) Time-delay trip (c) Shunt trip (d) None of the above (e) All of the above

Description : With which of the following, a circuit breaker must be equipped for remote operation ? (a) Inverse time trip (b) Time-delay trip (c) Shunt trip (d) None of the above (e) All of the above

Last Answer : (c) Shunt trip

The inverse Square Law is concerned with intensity of radiation using type D film of 200mm target to film distance, the exposure time was 0.25s. What would be the exposure for the same situation with 400mm target to film distance? M07********** A. 0.5s B. 1.0s C. 2.0s D. 0.25s E. 0.125s

Description : The inverse Square Law is concerned with intensity of radiation using type D film of 200mm target to film distance, the exposure time was 0.25s. What would be the exposure for the same situation with 400mm target to film distance? M07********** A. 0.5s B. 1.0s C. 2.0s D. 0.25s E. 0.125s

Last Answer : B. 1.0s

The mechanism of action of barbiturates differs from that of benzodiazepines in that they: A. Do not affect the GABA-benzodiazepine receptor-chloride channel complex B. Act as inverse agonists at the benzodiazepine receptor C. Increase the frequency of chloride channel opening without affecting its life time D. Have both GABA-facilitatory as well as GABA-mimetic actions

Description : The mechanism of action of barbiturates differs from that of benzodiazepines in that they: A. Do not affect the GABA-benzodiazepine receptor-chloride channel complex B. Act as inverse agonists at the ... without affecting its life time D. Have both GABA-facilitatory as well as GABA-mimetic actions

Last Answer : D. Have both GABA-facilitatory as well as GABA-mimetic actions

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

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

Last 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. 

Draw a typical time-current characteristic for IDMT relay.

Description : Draw a typical time-current characteristic for IDMT relay. 

Last Answer : Time-Current Characteristic for IDMT Relay: