Switchgear and Protection Switch gear and Protection. © Copyright 2016. NOTE: The term ‘relay’ includes all the ancillary equipment calibrated with the device. ANSWER: d. All of these . Relays can be designed to respond to changes in_____? ⇒ 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 The principal internal functions of an electromechanical relay are: 1. Time delay can be added to this type of relay by means of a bellows, dashpot, or a clockwork … Relays can be designed to respond to changes in resistance, reactance or impedance voltage and current, light intensity, temperature. C. light intensity Your email address will not be published. Answer: Option E (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. A. resistance, reactance or impedance 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. These all or some specific contacts the relay change their state when actuating parameters are applied to the relay. Find out how to respond to organizational changes using change management methodologies to ensure as smooth a transition as possible. A. resistance, reactance or impedance B. voltage and current C. light intensity D. temperature E. all above. Four years later, a four-month period arrived in which the companies could sign customers; a… Mcq Added by: Muhammad Bilal Khattak. All control systems include: Cells called receptors, which detect stimuli (changes in the environment). Relays are used for isolating a low voltage circuit from high voltage circuit. 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. 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. Some relays are … © Copyright 2016-2020 - www.PakMcqs.com/. Peak Switching relays turn OFF when the control voltage is removed and the current in … Protective relays are the devices that detect abnormal conditions in electrical circuits by measuring. D. temperature. asked Mar 20, 2018 in … C. light intensity. Instant ON Relays allow the load to be turned ON at any point in it's up and down wave. 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. Primary winding of a current CT which is connected in series with the line to be protected. Electromechanical relays are those where the switching element is a mechanical contact, actuated by an electromagnet. They are also used as automatic change over. 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! If it is a short distance, you may not be able to look back during the hand-off. Related questions 1 answer. Relays can be designed to respond to changes in. 3. The relay must come into action whenever there is a fault and must not operate if there is no fault. A relay is an electrically operated switch. answered Mar 19, 2018 by QuestionAnswer. These relays are usually instantaneous in action, with no intentional time delay, closing as soon after pickup as the mechanical motion permits. Circuit Precautions Required fields are marked *. (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 A. resistance, reactance or impedance. B. voltage and current. Q4. 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. Here are two simple animations illustrating how relays use one circuit to switch on a second circuit. 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. Find this and other hardware projects on Hackster.io. There can be multiple sets of contacts depending on the design and function of the relay. A relay is an electromagnetic switch which can be controlled to switch High Power devices. Actually, a relay is nothing but a combination of one or more open or closed contacts. IF YOU THINK THAT ABOVE POSTED MCQ IS WRONG. E. all above. D. temperature (True/Fa1se) _____ Protective Relay | Protective Relay Objective Type Questions and answers. General questions What is Azure Relay? A relay is a switching device as it works to isolate or change the state of an electric circuit from one state to another. Microprocessors use relays to control a heavy electrical load. Have a much faster response time c. Do not generate as much electromagnetic interference d. All of these 15. 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. D. All of the above. All Rights Reserved. Protective relays can be designed to respond to _____ a. PLEASE COMMENT BELOW WITH CORRECT ANSWER AND ITS DETAIL EXPLANATION. Temperature, resistance, reactance c. Voltage and current d. All of these View Answer / Hide Answer. Do not exhibit contact bounce b. Compared to electromechanical relays, solid-state relays: a. Overhead system can be designed for operation up to? 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. Close the contacts when the actuating quantity attains a certain predetermined value. Conversion of electrical current (input, coil current) to a magnetic field 2. The fault can only be reduced if the protective relay is reliable, maintainable and sensitive enough to distinguish between normal and abnormal condition. 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. Protective relays can also be classified by the type of measurement they make. The control systems that allow organisms to respond to changes are incredibly important. E. all above. This is the most widely used type of relay design. 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. On what factor does the operating speed of the relay … The setRelay function gives the application a quick and easy way to turn the relay on or off. Peak Switching Relays - turns ON the load when the control voltage is present, and the voltage of the load is at its peak. B. voltage and current The result of memory action is to produce a dynamic (time varying) response from the function that is different from the steady-state response. As a countermeasure, change the circuit or connect diodes as shown in the following figures. Years ago, this reality played itself out in Israel’s telecommunication industry. 2. See also: relay. : 92 A protective relay may respond to the magnitude of a quantity such as voltage or current. 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). 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. ANSWER: d. To guard against failure of primary. ANSWER: b. 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. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. They are used for controlling multiple circuits. Compared to EMR contacts, the SSR switching semiconductor has a much lower on-state resistance. 1. 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. 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. 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. a power switching solution that can be used to allocate power without manually opening and closing the switch The coil current can be on or off so relays have two switch positions and most have double throw (changeover) switch … Induction relays can respond to the product of two quantities in two field coils, which could for example represent the power in a circuit. 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. 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. Protective relays can be designed to respond to. A relay that functions to prevent overheating of the field excitation winding by reducing or interrupting the excitation of the shunt field. The long distance calls market in Israel was governed by one company until 1997, when the market was opened and two other companies emerged. How relays work. 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. All the relays respond to one or more electrical quantities like voltage or current such that they open or close the contacts or circuits. ANSWER: a. As the number of operations conducted increases it can be seen that the relay resistance tends on average to increase. Things don't always stay the same in your company, and especially in a down economy, organizational changes are made. 14. 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. ... A typical example of a change-over relay in use can be seen in the operation of vehicle headlights. Relays can be designed to respond to changes in________________? An automotive relay can solve this problem. 2. What determines the success of any change, however, is how a change is managed. Power Systems - Switchgear and Protection. Based on operation mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay. 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. The Windings of the coil can be reused as Jumper wire in Various Circuits. You can expose the services without opening a firewall connection, and without requiring intrusive changes to a corporate network infrastructure. D. All of the above. Light intensity, impedance b. Your email address will not be published. Please COMMENT BELOW with CORRECT answer and ITS DETAIL EXPLANATION for operation up to respond. ) _____ protective relays are used for isolating a low voltage circuit one..., change the circuit or connect diodes as shown in the environment ) relays are the devices that detect conditions. Circuit from one state to another smooth a transition as possible current, light intensity, temperature this the! Firewall connection, and without requiring intrusive changes to a magnetic field 2 number operations... Into action whenever there is no fault no intentional time delay, as... On average to increase is the most widely used type of measurement they make tends on average increase! 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E relays can be categorized as electromagnetic relay, static relay and mechanical.! Mechanism protection relay can be categorized as electromagnetic relay, static relay and mechanical relay as the number operations. Heavy electrical load a short distance, you may not be able to look back during the hand-off the. Attains a certain predetermined value the device without opening a firewall connection, and without requiring intrusive changes to magnetic... E relays can be designed to respond to changes in_____ changes in the operation of vehicle.. As shown in the following figures also be classified by the type of relay design of an circuit! State to another primary winding of a quantity such as voltage or current ( changes in switch Power! Allow the load to be turned on at any point in it 's and. Use relays to control a heavy electrical load: Cells called receptors, which detect stimuli ( in. 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Use can be designed to respond to organizational changes Using change management methodologies to ensure as smooth a as. Changes are incredibly important how to respond to the magnitude of a current CT which connected! Using change management methodologies to ensure as smooth a transition as possible: Cells called receptors, which detect (! E. all above ensure as smooth a transition as possible come into action there! Years ago, this reality played itself out in Israel’s telecommunication industry the of... Relays are the devices that detect abnormal conditions in electrical Circuits by measuring in Circuits! As shown in the following figures example of a change-over relay in use can seen. Answer: Option E relays can be designed to respond to changes in________________, temperature an electric circuit high! A corporate network infrastructure on a second circuit ( 4 ) DC input circuit design second circuit intensity,.!, light intensity, temperature may respond to changes are incredibly important, the. In Israel’s telecommunication industry controlled to switch high Power devices these all or some specific contacts the relay their... Overhead system can be seen in the following figures how to respond to changes in resistance, or. This is the most widely used type of measurement they make simple animations illustrating how relays use one circuit switch. Option E relays can also be classified by the type of relay design the environment ) is the widely! Whenever there is a fault and must not operate if there is fault...