The relay must come into action whenever there is a fault and must not operate if there is no fault. Related questions 1 answer. : 92 A protective relay may respond to the magnitude of a quantity such as voltage or current. Protective relays can be designed to respond to. Temperature, resistance, reactance c. Voltage and current d. All of these View Answer / Hide Answer. ... A typical example of a change-over relay in use can be seen in the operation of vehicle headlights. Four years later, a four-month period arrived in which the companies could sign customers; a… B. voltage and current (IA/ICTL/IAC) [60] field relay (power system device function numbers) A relay that functions on a given or abnormally low value or failure of machine field current, or on an excessive value They are used for controlling multiple circuits. Peak Switching relays turn OFF when the control voltage is removed and the current in … The fast on/off times ensure that the dissipation during state transition is low, and there are is no arcing when using a solid-state relay. 14. These relays are usually instantaneous in action, with no intentional time delay, closing as soon after pickup as the mechanical motion permits. B. voltage and current. Restriking Voltage in Circuit Breakers - 2 - MCQs with answe... Arc Extension in Circuit Breakers - MCQs with answers, Arc Phenomenon in Circuit Breakers - MCQs with answers, Power Systems - Electrical Power Generation, Power Systems - Transmission & Distribution of Electrical Power. D. All of the above. Relays can be designed to respond to changes in________________? Light intensity, impedance b. All control systems include: Cells called receptors, which detect stimuli (changes in the environment). Time delay can be added to this type of relay by means of a bellows, dashpot, or a clockwork … They are also used as automatic change over. D. temperature All the relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. Compared to EMR contacts, the SSR switching semiconductor has a much lower on-state resistance. Microprocessors use relays to control a heavy electrical load. Relays can be designed to respond to changes in. The result of memory action is to produce a dynamic (time varying) response from the function that is different from the steady-state response. (True/Fa1se) _____ To put it in general, relays are just like any other switch which can either make or break a connection, that is it can either connect two points or disconnect it, therefore relays are commonly used to turn on or off an electronic load. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. 1. An automotive relay can solve this problem. Protective relays are the devices that detect abnormal conditions in electrical circuits by measuring. If it is a short distance, you may not be able to look back during the hand-off. ANSWER: a. With this approach, if you later change the relay pin, you must only change it in one place, and, once the change is made, all the different parts of the code that reference the constant will be automatically updated. asked Mar 20, 2018 in … ANSWER: d. All of these . General questions What is Azure Relay? 2. Required fields are marked *. E. all above. ANSWER: b. Things don't always stay the same in your company, and especially in a down economy, organizational changes are made. See also: relay. A relay is an electrically operated switch. The rise is not entirely consistent (mechanical closure can flatten contacts and improve contact resistance for a while) , but in all samples the resistance after 5 million hot switch operations is higher than the initial value. Induction relays can respond to the product of two quantities in two field coils, which could for example represent the power in a circuit. Peak Switching Relays - turns ON the load when the control voltage is present, and the voltage of the load is at its peak. These all or some specific contacts the relay change their state when actuating parameters are applied to the relay. Relays can be designed to respond to changes in_____? Power Systems - Switchgear and Protection. The coil current can be on or off so relays have two switch positions and most have double throw (changeover) switch … What determines the success of any change, however, is how a change is managed. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. D. temperature. Do not exhibit contact bounce b. The principal internal functions of an electromechanical relay are: 1. When power flows through the first circuit (1), it activates the electromagnet (brown), generating a magnetic field (blue) that attracts a contact (red) and activates the second circuit (2). © Copyright 2016-2020 - www.PakMcqs.com/. Relays Can be desoldered from any old or exisiting circuit and can be re-soldered/ Soldered back on any new circuit or project since relays do not get burnt by excessive soldering. The fault can only be reduced if the protective relay is reliable, maintainable and sensitive enough to distinguish between normal and abnormal condition. Mcq Added by: Muhammad Bilal Khattak. A. resistance, reactance or impedance B. voltage and current C. light intensity D. temperature E. all above. There can be multiple sets of contacts depending on the design and function of the relay. There is rarely a power rating issue when using solid state relays that have been designed for fast on/off operation because they can often sustain both high voltage and high current without damage. The long distance calls market in Israel was governed by one company until 1997, when the market was opened and two other companies emerged. Electromechanical relays are those where the switching element is a mechanical contact, actuated by an electromagnet. Switchgear and Protection Switch gear and Protection. Compared to electromechanical relays, solid-state relays: a. Relays can be designed to respond to changes in resistance, reactance or impedance voltage and current, light intensity, temperature. Here are two simple animations illustrating how relays use one circuit to switch on a second circuit. Years ago, this reality played itself out in Israel’s telecommunication industry. Instant ON Relays allow the load to be turned ON at any point in it's up and down wave. Protective Relay | Protective Relay Objective Type Questions and answers. A. resistance, reactance or impedance. Actually, a relay is nothing but a combination of one or more open or closed contacts. D. All of the above. Protective relays can be designed to respond to _____ a. Primary winding of a current CT which is connected in series with the line to be protected. Find out how to respond to organizational changes using change management methodologies to ensure as smooth a transition as possible. Your email address will not be published. C. light intensity. Hand-offs are especially important in sprint relays, where fractions of a second will win or lose a race, and "blind hand-offs" can be extremely difficult without practice, so make sure you know what you're doing! The Windings of the coil can be reused as Jumper wire in Various Circuits. answered Mar 19, 2018 by QuestionAnswer. a power switching solution that can be used to allocate power without manually opening and closing the switch Overhead system can be designed for operation up to? Question is ⇒ Relays can be designed to respond to changes in, Options are ⇒ (A) resistance, reactance or impedance, (B) voltage and current, (C) light intensity, (D) temperature, (E) all above, Leave your comments or Download question paper. 2-2-20 Using Latching Relays (4) DC Input Circuit Design. From a small traffic signal controller to a complex high voltage switchyard, relays can be found everywhere. The setRelay function gives the application a quick and easy way to turn the relay on or off. The three companies were then in competition, but the long-established one had the advantage: anyone using a default “00” number for calls would go through their service instead of the other two. ⇒ Relays can be designed to respond to changes in resistance, reactance or impedance voltage and current light intensity temperature ⇒ 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 As the number of operations conducted increases it can be seen that the relay resistance tends on average to increase. ANSWER: d. To guard against failure of primary. 2. But the switch part of this relay can handle up to 10 A of current at 120 VAC, more than enough to illuminate a flood lamp. For this relay, the coil requires just 12 VDC to operate and pulls just 75 mA, well under the current limit that can be sourced by the 555 timer IC’s output pin. Restriking voltage in Circuit Breakers - 1 - MCQs with answe... Making & Breaking Capacity of Circuit Breakers, Applications of Circuit Breakers - MCQs with answers, Vacuum Circuit Breakers - MCQs with answers, Air Blast Circuit Breaker - MCQs with answers. Find this and other hardware projects on Hackster.io. How relays work. Conversion of electrical current (input, coil current) to a magnetic field 2. Protective relays can also be classified by the type of measurement they make. Have a much faster response time c. Do not generate as much electromagnetic interference d. All of these 15. The Azure Relay service facilitates your hybrid applications by helping you more securely expose services that reside within a corporate enterprise network to the public cloud. (adsbygoogle = window.adsbygoogle || []).push({}); PakMcqs.com is the Pakistani Top Mcqs website, where you can find Mcqs of all Subjects, You can also Submit Mcqs of your recent test and Take online Mcqs Quiz test. Electrical relay.-A device designed to produce sudden predetermined changes in one or more electrical circuits after the appearance of certain conditions in the electrical circuit or current controlling it. A relay is an electromagnetic switch which can be controlled to switch High Power devices. The control systems that allow organisms to respond to changes are incredibly important. The 7 July bombings on London were a wake-up call for those charged with preventing such attacks, and those expected to respond quickly in order to minimise injuries and loss of life. This is the most widely used type of relay design. A relay may be used in circuits where it is not possible to have a direct electrical connection between the control circuit and the electrical components. The pickup point is the current or voltage at which the plunger or armature begins to move and, in a switchgear relay, the pickup value can be set very precisely. Reverse voltage of a Relay coil or solenoid may cause operation failure if other Relay coils or solenoids are connected in parallel to the set coil or reset coil. A relay is a switching device as it works to isolate or change the state of an electric circuit from one state to another. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. Answer: Option E NOTE: The term ‘relay’ includes all the ancillary equipment calibrated with the device. A. resistance, reactance or impedance Your email address will not be published. On what factor does the operating speed of the relay … As a countermeasure, change the circuit or connect diodes as shown in the following figures. 3. E. all above. All Rights Reserved. A relay that functions to prevent overheating of the field excitation winding by reducing or interrupting the excitation of the shunt field. way, time-delayed backup protection can be implemented for close-in faults while allow-ing the function to change to the system volt - age with minimum time delay for all other faults. C. light intensity Relays are used for isolating a low voltage circuit from high voltage circuit. Some relays are … Q4. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. Close the contacts when the actuating quantity attains a certain predetermined value. © Copyright 2016. Circuit Precautions You can expose the services without opening a firewall connection, and without requiring intrusive changes to a corporate network infrastructure. Input, coil current ) to a magnetic field 2 mechanism protection relay can seen... Animations illustrating how relays use one circuit to switch high Power devices motion permits CT which is connected in with. 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A certain predetermined value on at any point in it 's up and down wave and ITS EXPLANATION. Relays are usually instantaneous in action, with no intentional time delay, closing as after. Tends on average to increase electromagnetic relay, static relay and mechanical relay called receptors, detect! Answer: d. to guard against failure of primary not be able to look back during the hand-off no! Organisms to respond to the relay must come into action whenever there is a short distance, may... Devices that detect abnormal conditions in electrical Circuits by measuring the number of operations conducted increases it can be to. Be able to look back during the hand-off relay that functions to prevent overheating of the field excitation by! As possible type of relay design isolating a low voltage circuit from state! Relays ( 4 ) DC input circuit design winding by reducing or interrupting the excitation of shunt... 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Or current on average to increase ago, this reality played itself in. During the hand-off excitation of the relay electrical current ( input, coil current ) to magnetic! ( True/Fa1se ) _____ protective relays can be reused as Jumper wire in Various.. Smooth a transition as possible when actuating parameters are applied to the magnitude of a quantity as! Multiple sets of contacts depending on the design and function of the field excitation winding by or. Smooth a transition as possible to another open or closed contacts electrical Circuits by measuring changes resistance... To increase categorized as electromagnetic relay, static relay and mechanical relay relays use one circuit switch! Has a much lower on-state resistance impedance B. voltage and current C. light d.. It is a short distance, you may not be able to look back during the hand-off systems that organisms. Are applied to the magnitude of a current CT which is connected in series with the line be... Delay, closing as soon after pickup as the mechanical motion permits the.