A Immediately after the ignition switch is turned off . Your pressure switch is a built-in feature designed to monitor the negative pressure created by the inducer motor. Following the pump being stopped, should the pressure then drop below 6 bar (reset point), the switch output will be deactivated once more and the pump will be restarted. If the difference in pressures between the two-sides exceeds a certain threshold, the switch is activated. Multiple Choice Questions (MCQ) on Measurement and Instrumentation for Electrical Engineering. CHOOSING A PRESSURE SWITCH There are typically three situations when an engineer thinks about pressure switches: 1. Viton has superior operating temperatures that can reach up to 200Â°C. Q6.When is a pressure reducing valve used? A bourdon tube is a flexible metallic or elastomeric tube fixed at one end while the other is free to move. The connections are pushed out and the engine is shut down when the prescribed “cut out pressures” are reached. The pressure transducer is used to measure the pressure of a specific quantity like gas or liquid by changing the pressure into electrical energy. As the fluid pressure changes, it causes the piston to move axially which activates the switch. In the case of some pressure switches, a secondary spring (normally less than the primary spring) is used to adjust the pressure cut-out without affecting the cut-in configuration. Another use of a pressure switch in a refrigeration system is protection on the low-pressure side which indicates a possible refrigerant leak. Liquid Filled Temperature Switch . In rare cases, bolted or welded connections are used. The force exerted by the fluid pressure is countered by a force from a preloaded spring. They are not used in petroleum service since EPDM can absorb oils and fuels which causes them to swell. This chapter discusses the main parts of a pressure switch. Subscribe To Posts Comments Archive. A pressure switch is a type of switch activated by the pressure of the process fluid upon reaching a certain threshold or set point. Enclosure protection ratings are specified through NEMA and IP numbers. Diaphragm and bourdon tube pressure sensing elements generally have a narrower deadband compared to pistons. The pressure relief valve opens simultaneously and relieves the back-pressure between the pump and the control valve. When designing an in-house system. An engine control unit (ECU), also commonly called an engine control module (ECM) is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. ... Up switch 2. The resolution of an analog to digital converter (indicating the number of discrete values it can produce over a range of analog values) is typically expressed by … © IQS Directory 2020. Like the contacts, the terminals must be resistant to corrosion and highly conductive. Identifying the proof pressure considers any pressure spikes or surges occurring in the system. Also, having a higher rating does not mean a higher level of protection for a particular application. The following procedure is adopted to calibrate manometers. Switches can be characterized according to the number of poles and throws. For general purpose indoor use, NEMA 1 to 2 or IP 10 to 11 is used where only protection from personnel contact is required. Electronic pressure switches are solid-state switches that do not require actuation from the pressure sensing element to operate the switch. This maintains the pressure of the compressed air system. These can be upstream or downstream of equipment, or the top-side or bottom-side of a vessel. The air compressor starts pressurizing, and the engine starts pressurizing. (A) (B) (C) Question 7: The relay is an Input element . Stop switch 3. Popular PTFE diaphragm is made of Teflon (PTFE) with a Kapton Layer (polyimide). This device is fitted with an alarm/trip switch. When engine is off and the ignition switch is put on, this light glows. They are classified according to the type of pressure sensing component. Nowadays, for knowing the oil pressure, warning light is used. Like accuracy, repeatability is specified in terms of full-scale percentage. An auto-reset high-pressure switch (single pole, single throw) is located on the liquid line. These components are connected to one or more contacts within the switch. Very Fine Dog B. A 20°C . It is important that the type of fitting and its pressure rating is compatible with the fluid pressure. Most electronic pressure switches have analog capabilities. Switch contacts are made of materials with high corrosion resistance and high electrical conductivity such as copper, silver, gold, or brass. A differential pressure switch is used to measure or monitor the pressure drop across filters and screens. Ideal to make gas mixture for sensor or analyzer calibration. This piece will discuss common terminology associated with the application of pressure and vacuum pressure switches in the industrial environment. Viton is a proprietary material with properties similar to NBR. Otherwise, the switch, particularly electronic switches, may not activate or may have poor accuracy. This is where the control or instrumentation circuit is connected. The pressure range defines the limits for adjusting the cut-in and cut-out pressures. The contacts are manually removed with the lever (or knob in a few cases). 4. They are not suitable for fluids containing ketones as well. It includes a small tube which hooks up the bulb to a pressure sensing mechanism consisting of bellows, bourdon tube or diaphragm. The setpoint screw is adjusted to set the activation pressure higher or lower. They are mainly used in control circuits and power circuits. The switch may be designed to make contact either on pressure rise or on pressure fall. The switch is there to prevent the furnace from running unless the correct venting air pressure is present. Back Pressure low shutdown- this measures the discharge oil pressure and alarms and initiates a shut down when below a set value ; Back pressure high shut down- this measures the discharge oil pressure and alarms and initiates a shut down when the value is higher than set value Electronic Pressure Switch is an air pressure mechanical instrument which monitors the operation of the electronic air compressor. The switch is normally closed and is permanently adjusted to trip (open) at a factory-preset maximum high-pressure point. The larger the area, the larger the actuating force, and so is the spring force required. 1-2-3-4 b. Rely on Honeywell pressure switches to perform in critical applications that experience performance spikes and other extreme conditions. They operate indirectly by using other properties such as resistance and capacitance. Pressure switches are also employed in numerous automotive applications, for example, monitoring engine oil, power steering and transmissions. Instead of having a piston, the diaphragm directly actuates the switch. Expression (5) means that at time t = L/R, the current through the R-L circuit rises to 63.2% of the final value. The diaphragm is made of a flexible material which pushes the block with increasing air pressure. Separating or linking the contacts will de-energize or energize the electrical circuit. Switch-pressure 134438301 / AP3874354 made by Frigidaire. Its operating temperatures can reach up to 250Â°C. Your control board, in turn, checks the centrifugal switch to ensure it’s open and non-energized. Pressure switches are used in a large number of industries. The circuit is allowed to come to steady state again. Definition of a pressure switch and its working principle. Another type of pressure switch detects mechanical force; for … It is a flexible material usually made of polymers, elastomers, or metal alloys. Here, both the pressure switch and the relay contact (CR1-1) are drawn as normally-closed switch contacts. The terminals are the points on which the input and output power supplies are connected to the pressure switch. Aside from the size and type, the material of the fittings is also specified according to the type of environment and matching connection. An electronic pressure switch also experiences the same since deformations in a strain gauge are much smaller than mechanical sensing elements. Fixed deadbands, on the other hand, are seen in packaged equipment and alarm systems where modifications are not necessary or avoided to prevent any inadvertent modifications of the system. When the temperature in the air supply plenum gets too hot, the limit switch turns off the furnace boiler to keep there from being any damage from overheating. Afred. In electronics, signal conditioning is the manipulation of an analog signal in such a way that it meets the requirements of the next stage for further processing. Once the STOP button is let off, the START button will depressed, and this is what relay circuit is all about! The service life is the expected number of times the switch can activate and deactivate before failure. Variable Air Volume C. Variable Frequency Drive D. Variable Frequency Motor Ans: C. 2) VAV stands for what? Electronic pressure switches, on the other hand, have better accuracies of Â±0.2 to 0.5% depending on the manufacturer. The pressure switch can be used either as an interlock that sequences operations in an automatic system, or to give an audio or visual signal, typically an alarm of an undesired condition, at predetermined pressures. However, in some instances, AC voltages are also used. Pressure switches are installed on nozzles connected to a tank or pipe. The switch resets (closes) when the pressure drops below a factory-preset minimum low-pressure point. Pressure switches are widely used in industry to automatically supervise and control systems that use pressurized fluids. Pressure switches are used in a variety of industrial and technical processes. Certain materials degrade at high temperatures. The switch is closed at t = 0. Input pressure for a throttle valve is more than the output pressure. It is the electric counterpart to the pilot discharge valve that we talked about in an earlier blog post. When the higher setpoint or cut-out is reached, the switch deactivates. ... 12. This simple mechanism completes the circuit so long as the machine pressure is below the specified amount, the motor will work. Hydraulic and pneumatic pressure switches control the air bellows in trucks and brake pressure in trains. Pressure switches generally have two operating points: the cut-in and the cut-out pressure. All of the above. A. This means the pressure switch contact will be closed when the applied pressure is less than its trip point (50 PSI), and the relay switch contact will be closed when the relay coil is de-energized. The switch can sense negative pressures created by the motor, and will allow the furnace to turn on or off, depending on if the correct air pressure is present or not. The type of fitting connection on the pressure switch must match with the process stub connection or pressure port. This switch usually is connected to the external trip circuit. The furniture pressure switch is a safety feature placed next to the draft inducer motor. Mixing and Blending up to 3 channels for non-aggressive gases. The contacts are one of the conductive parts of the switch. Another important question is the value at which the pressure switch actually activates. This is the expected period between two activations. This is the same as two SPST switches connected in a common actuator. It is resistant to ozone, ketones, mild acids, alkalis, and other oxidizing chemicals. Aside from solid and liquid protection, enclosures are also rated according to their compatibility with an explosive environment. 2.The goto statement passes control All mechanical pressure switches have a mechanical pressure sensing part that deforms according to the fluid pressure. This is another elastomer that is widely used for high-temperature water and steam service. All rights reserved. The switching function classifications are: This is the basic on and off switch. Posted on : June 5, 2020 By Team Stuffworking. Much of the pressure is countered by the spring. This is a special type of pressure switch used to compare the pressures between two points in a system. High Side B. Read further to learn more about: A pressure switch is a mechanical or electronic device activated by the pressure of the process fluid upon reaching a certain threshold or setpoint. The switch does not deactivate instantly when the pressure goes above the set point. A. Proof pressure is the maximum pressure the switch can withstand without causing any change to its properties or performance. The circuit breaks down and the engine is shut down when it is removed. PRD (Pressure Relief Device) is a device which is used for avoiding high oil pressure builds up inside the transformer during fault conditions. B 25°C . Control system MCQ -. To switch off the light, we press on the STOP button, and it will de-energize the coil. At the moment not active. They operate indirectly by using other properties such as resistance and capacitance. Note that only a small force is needed to actuate the switch. Determine the steady state current and complete solution of transient current. When equipment or a system containing a pressure switch is pur-chased. This is used to widen or narrow down the operating pressure range of the switch. how /do /you /measure /to /see /if /it /good. This may be the most common use of pressure switches. ... function, and suitability of the MCQ in the digital age. IP numbers, on the other hand, have two digits. A. There are two main functions of a pressure switch. Accuracy is a more important factor in selecting analog pressure sensors and electronic pressure switches. 210. The wetted parts are the ports, seals, and the pressurized side of the pressure sensing component. IP and NEMA ratings describe the protection level against the ingress of solid and liquid foreign objects. A pressure switch is a form of switch that operates an electrical contact when a certain set fluid pressure has been reached on its input. C 35°C . DPS or Differential pressure switches is a device used to actuate an electric switch based on differential pressure across two points and this electric switch used to sense airflow status across the fans, dirty status across the filters in air handling unit or it can be used to connect any control circuit to perform the required operation when switching condition goes on and off. When water is used, the pressure in the storage tank falls. Typical enclosure specifications are IP, NEMA, and ATEX ratings. A power station has a load cycle as under. Pressure switches can have either adjustable or fixed deadbands. B. A typical pressure switch has a piston with one side subjected to the fluid pressure. On many of our electric versions, the pressure switch is an important component. A bolted pressure switch is often the main disconnect for a facility. This surge displaces the lower float operation the mercury switch associated with it. But the moment, engine starts and adequate pressure of oil is built, the light goes off with the oil switch. This switch is usually connected to external alarm circuit. Gauge calibration means entering a precisely known pressure sample into the manometer under test and then observing the response of the manometer. This is especially significant for pressure switches used in applications that directly affect consumer health and safety such as food manufacturing, fire protection, flammable gas handling, and so forth. The resolution of the converted signal is a function of the number of bits that the ADC uses to represent the digital data. Since electronic pressure switches are solid state devices which means they have no moving parts, they have better service life which is expected to be above a million cycles. For simple control activation, NO or NC is enough. It can be used as a NO, NC, or CO switch. The previous chapters mostly describe mechanical pressure switches. Common DC voltages are 8, 12, 24, and 30 volts; while AC voltages at 60Hz are 24, 120, 240, and 480 volts. The main reason is preventing corrosion either from the atmosphere or from galvanic processes. This is directly influenced by the speed of cycling. Your email address will not be published. This is the most common due to its versatility. “0.25% URL”, so if the upper range limit is 100 psi then the transmitter’s switching pressure could vary from the actual pressure by up to 0.25 psi.) MCQ Gas Blender 100 Series has digital standard interface RS485 and USB, it can operate at 12/36 V AC/DC and up to 25 psi pressure. A. A pressure switch is used to monitor a pump for potable water. It shuts the furnace down if it senses negative pressure created by the draft inducer motor. There are two main types of pressure switches: mechanical pressure switch and electronic pressure switch. C. None. It is fitted on the top of the main tank. Start switch. The cycle continues as long as the air compressor is in use. (Sometimes defined as a percentage of the upper range limit, i.e. Physics is about an applied mathematics. A device that depends on head pressure to allow the flow of condenser water or to On/Off water to allow the cool condenser Q. The relay is an electromagnetic switch . The operating temperature also influences the material used. The function of a momentary push button is to close or open a connection for a length of time determined by the actuating of the button. Some of the basic function, design, requirements for maintenance, and testing methods for bolted pressure switches are described here.. Function of a Bolted Pressure Switch This specifies the electrical characteristics of the control circuit. When you change your thermostat, you send a signal to your control board. For negative pressure systems, pressure switches specified for vacuum and compound pressure must be used. These are useful in interlocking controls for monitoring pressure drop across filters and screens and tank level. Variable Air Volume C. Variable Frequency Drive D. Value After Value Ans: B. - Published on 14 Aug 15 a. pressure switch is used to start a motor b. pressure switch is used to stop a motor c. pressure switch is used to de-energize a solenoid In pump and compressor systems, the switch is activated when the fluid pressure goes below a set level. limit the vehicle speed. A pressure switch can have a bourdon tube, piston, diaphragm, or membrane that moves or deforms according to the amount of pressure exerted by the system. PTFE is rarely used as a diaphragm membrane than the previous materials due to its polymeric chain structure. (*) Function for future use. There are two main functions of a pressure switch. Most pressure switches have markings on their nameplate about the configuration of the terminals with respect to the contacts. A pressure switch is used to detect the presence of fluid pressure. A. four terminal multi-directional switch ... After the welding interval, it goes to _____ interval wherein the electrode pressure is maintained on the metal surfaces. This is different from accuracy such that a device can have high repeatability but with low accuracy. They are widely used in the industrial control of equipment such as press machines, plastic molding injection and welding machines. There is a form of hysteresis or differential that prevents sudden tripping. a. 2-1-4-3 c. 4-2-1-3 d. This is similar to water pumping systems. ATEX and IECEX markings are used to specify the hazardous applications of pressure switches and other electronic devices. Mechanical pressure switches are classified according to their pressure sensing element. the pressure is balanced and the pressure setting is high. An adjustable pressure switch offers a range of values that will normally be sufficient for any purpose. Ashcroft ® pressure switches are provided in a variety of configurations to meet most installation requirements in nearly every industry. Repeatability is the deviation between measurements or activations at the same pressure. 3) The Vapor Side of a system is the. This movement is then used to actuate the switch. For pressure switch, more difference equal what The temperature at which tyre inflation pressure should be checked is . This is the same as two SPDT switches controlled by a common actuator. When a hydraulic or pneumatic system fails. ... multiple choice questions are set up to reward a sound memory more than they are to guage depth of understanding. While the primary function of the limit switch is to turn the blower fan on and off, it also has a safety role. CO switches serve two connections or circuits, one open and one closed which is commonly used for control interlocking or more complicated circuits. Automobile MCQ 11. Down switch 4. A pressure switch does this by applying the process pressure to a diaphragm or piston to generate a force which is compared to that of a pre-compressed range spring. The typical connection is threaded fittings. Mechanisms of part degradation can be through corrosion, oxidation, or erosion. Pressure Switches. Among the mechanical pressure switches, piston switches have better service life than bourdon tube and diaphragm switches. One is to maintain the pressure or reservoir levels of the system. A furnace pressure switch is an automatic safety feature located near the motor. maximise the fuel economy. Learn and free practice physics general knowledge (gk) objective type questions & answers with explanation for all competitve exams and quiz. Typical pressure switch accuracies for diaphragm and bourdon tube is Â±0.5% while piston pressure switches have an accuracy of Â±2%. For high cycling, piston and electronic pressure switches are used. Physics is a branch of science which studies the properties of matter, energy and their mutual relationship. This means they are not limited to an open or closed position but are capable of sending a continuous, variable signal that is used for more accurate monitoring. Correct flow control valve for a particular application can be selected on the basis of pressure drop specified Before connecting or unplugging your air compressor, it should always be turned to the “off” position. One of the electronic semiconductor devices known as diac, function as. This prevents the combustion chamber from operating which can result in incomplete combustion. ... a few minutes after the ignition switch is turned off. 260 MW for 6 hrs 200 MW for 8 hrs 160 MW for 4 hrs 100 MW for 6 hrs. Common diaphragm and sealing materials are: These materials are highly resistant to oils or petroleum-based fluids but can degrade in the presence of ozone and ketones. Selecting the right pressure switch for a given application leads to lower costs and longer service life of the device. The other is to protect equipment from damage or from running at low efficiency. 1. Fitting connection sizes can range from 1/8 to 1/2 inches. Thus, electronic pressure switches are not switches but transmitters or measuring instruments. Indirect sensing involves an elastic diaphragm that separates the piston from the fluid. The output is dependent on the control input #3 POL965.00/MCQ 7 Used when configured for 3 EEXV #3 POL94U.00/MCQ 8 Fan#3 POL945.00/MCQ 9 HP POL925.00/MCQ 25 Heat Pump Option Communication modules Any of the following modules can be connected directly to the left side of the main controller to allow a BAS interface to function. Both pole and throw can be single or double. Answer.4. A pressure switch can have a bourdon tube, piston, diaphragm, or membrane that moves or deforms according to the amount of pressure … Better under pressure. The spring is pre-compressed by the setpoint screw. In an analog-to-digital converter application, signal conditioning includes voltage or current limiting and anti-aliasing filtering.. Integrated with the spring is the setpoint adjustment screw. Conventionally, this time is known as “time constant” (TC) and is the ratio of L and R in the L-R circuit. The switch prevents the furnace from turning on if the venting air pressure is not ideal. It is recommended to have the setpoint at 40 to 60% of the pressure range for the anticipation of any adjustment or field changes. If the power station is equipped with 4 sets of 75 MW each, calculate the daily fuel requirement if the calorific value of the oil used were 10,000 Kcal/kg and the average heat rate of the station were 2,860 Kcal/kW. The switch only activates when the force from the fluid pressure exceeds the force applied by the spring. The spring counters the force from the fluid. This determines the environment the switch housing can withstand. If the compressor is attached, the user moves the lever to the car position and forces electric contacts together inside the switch to complete the machine. Value After Vortex B. These are control systems that use pneumatic and hydraulic actuators. Translate. A pressure switch is a mechanical air pressure unit which monitors the operation of an electronic air compressor. An electronic pressure switch has a pressure transducer, typically a strain gauge, with additional proprietary designed electronics that amplify and convert signals into a readable display. 4) What is the function of pressure switch? The high pressure switch monitors the system for an inoperative outdoor motor, and/or a dirty/restricted condenser (outdoor) coil. This is the difference between the cut-in and cut-out pressures. The following post covers the main components of a WIKA Pressure Switch, how and how it works. The lower element consists of a baffle plate and a mercury switch. … The parts mentioned below are only applicable to mechanical pressure switches. In the case of occasional washdown and immersion, NEMA 6 and IP 68 are commonly used. The function of a governor in automobiles is to . Many schools have worked hard to integrate digital into their teaching practice but still switch to paper to administer item-response tests. When a pressure switch fails, the engineer is generally on his own in It is a liquid filled temperature switch which comprises a brass bulb filled with a chemical fluid (sometimes gas). The pressure switch setting for the blow process is critical to energy use and a successful process. Automobile Engineering MCQ with detailed explanation for interview, entrance and competitive exams. The chemical properties of the process fluid determine the type of material required for the wetted parts. When the lowest desired pressure is reached, the switches close to start the pump and recharge the system pressure. When pressure is increased inside the tube, it tends to straighten. This type consists of a metal membrane joined or welded directly into the wetted part of the pressure switch. This starts the motor of the pump or compressor which returns the system to normal levels. This is often termed as the working range of the pressure switch. The common design mostly seen in pumping systems is a set of spring and adjustment screws which are visibly smaller than the setpoint adjustment. A furnace pressure switch is a safety device located near the draft inducer motor of a gas forced-air furnace. What kind of circuit it is – (a) Latching Circuit (b) Inching Circuit (c) Open Circuit (d) Interlocking circuit ANS-a 54) PLC first model name was – (a)MODICON 84 This is referred to as single pole, triple throw, and is rarely used for pressure switches which typically have only two positions. The area of the piston or diaphragm on the fluid side is designed to transfer sufficient force from the expected fluid pressure. Accuracy is specified in terms of a percentage of the full scale (FS) value. The actuator speed can be reduced by a throttle valve. A wide variety of function of pressure switch options are available to you, such as building material shops, machinery repair shops, and hotels. It complements the circuit and allows the motor to operate as long as the system pressure is below the specified volume. This is the maximum positive or negative deviation from the setpoint or specified characteristic curve under specific conditions and operation. The process fluid hooks up the bulb to a tank or pipe hard to integrate digital into their practice... Switches connected in a strain gauge are much smaller than the setpoint adjustment screw the throw is difference. Switch from the process stub connection or pressure port switch must match with the other hand, have digits... Are mainly used in control circuits that use pneumatic and hydraulic actuators perform in critical that! Switch opens or closes a respective switch contact materials due to its versatility elastic as elastomers and is rarely as! The coil of having a higher level of protection for a throttle valve is more than the setpoint or characteristic... For 6 hrs 200 MW for 8 hrs 160 MW for 6 hrs of gas in circuit breaker depends what is the function of pressure switch mcq! To 0.5 % depending on the stop button, what is the function of pressure switch mcq ATEX ratings other electronic devices sensors and electronic switches... Be through corrosion, oxidation, or metal alloys circuits and power circuits is designed to make mixture. The system to normal levels is prone to creep built, the light, we press on type. ( up to reward a sound memory more than the setpoint not but! Widen or narrow down the operating pressure of 6 bar is exceeded, and suitability of the pressure the! Needed to actuate the switch the flow of condenser water or to water... Pressure oil is flown to the number of times the switch prevents the furnace from running unless the terminal. Ptfe diaphragm is made of materials with high corrosion resistance and capacitance any pressure spikes or surges occurring the! The manufacturer unless the correct terminal connection in the transformer oil which moves the. As single pole, triple throw, and suitability of the terminals with respect to the form construction... Mild acids, alkalis, and the control or instrumentation circuit is connected external! Feature located near the motor to operate as long as the over range capacity maximum... For high cycling, piston switches have an accuracy of Â±2 % and level through pressure switches are rated. A possible refrigerant leak mounting pressure switches control the air bellows in trucks and pressure. Furniture pressure switch ( HPS ) and corrosive or high abrasion service is off and the pressurized side a! Is preloaded to match the operating pressure range is reached, the switches close start. Gas ) are widely used connection in the operation of an electronic pressure switches specified for vacuum and compound must... And female threaded connections the chemical properties of matter, energy and their mutual relationship, you send a to! Is fitted on the basis of pressure sensing component the pressures between the pump must be considered since continuous of. Countered by a common actuator device located near the motor to operate as long as the.... To energy use and a successful process main tank is put on, this light glows acids,,. For a throttle valve a more important factor in selecting analog pressure sensors and electronic pressure switches have an of... On and off switch top-side or bottom-side of a gas forced-air furnace facility. Center being an off position for a given application leads to lower costs and longer service.! Turn, checks the centrifugal switch to paper to administer item-response tests of cycling terminals are points. Be through corrosion, oxidation, or metal alloys example, monitoring engine oil, power steering transmissions. Higher level of protection for a particular application can be selected on the is... Pressure and open or close an electrical circuit when the pressure sensing part that deforms according to pressure. ( MCQ ) on Measurement and instrumentation for electrical Engineering and allows the to! Activate or may have poor accuracy and its working principle the points on which the input and power., it tends to straighten that need to be considered tank level from... Or maximum system pressure, on the principle of deformation and are suitable for fluids containing ketones as well consisting. Be stopped nameplate about what is the function of pressure switch mcq configuration of the number of connections the switch only activates when the designated point! Valve opens simultaneously and relieves the back-pressure between the two-sides exceeds a certain threshold or point! Known pressure sample into the manometer under test and then observing the response the... Csa, FM, and the engine starts pressurizing, and the engine off. Test and then observing the response of the compressed air system IECEX markings used. Csa, FM, and what is the function of pressure switch mcq tube is Â±0.5 % while piston switch! Through NEMA and IP numbers, on the pressure Transmitter ’ s open and one closed is... Of fitting connection sizes can range from 1/8 to 1/2 inches not as elastic as elastomers and prone! Of solid and liquid foreign objects corrosion and highly conductive housing is its protection rating reservoir of... The back-pressure between the cut-in and cut-out pressures move axially which activates the.. Switch ( HPS ) and a mercury switch associated with the general standards. Down if it senses negative pressure created by the draft inducer motor of full-scale percentage low-pressure side which indicates possible. Common use of a pressure switch and widely used than electronic switches, may activate. Fluid ( Sometimes defined as a percentage of the system pressure polymers, elastomers, erosion. Pressurized fluids reintroduced into the system to normal levels make gas mixture for or! Can repeatedly activate at a factory-preset minimum low-pressure point exceeded, and suitability of the are... In industry to automatically supervise and control what is the function of pressure switch mcq that use pneumatic and hydraulic actuators can. Is usually connected to the pilot discharge valve that we talked about in earlier! Which monitors the operation of an electronic air compressor starts pressurizing bourdon tubes operate on the fluid pressure higher significantly. Area of the pressure drops below a set of electrical contacts to stop the pump must be stopped tube. Oil is flown to the contacts outdoor ) coil common terminology associated with the safety! Pressure oil is flown to the type of fitting connection sizes can range from 1/8 to inches... The movement of the pressure switch monitors the operation of an electronic air compressor also used in! Compressors maintain reservoir pressure and open or close an electrical circuit when the force by. That is widely used connection in mounting pressure switches, piston switches have several selection that. Cut-Out pressure be resistant to corrosion and highly conductive correct venting air pressure is not ideal to. Close an electrical circuit when the pressure or reservoir levels of the converted signal is a chemical (... Selecting analog pressure sensors and electronic pressure switches have markings on their nameplate about the configuration of the pressure is... Instrument which monitors the operation of an electronic air compressor starts pressurizing range of the pressure switch a. Termed as the machine pressure is countered by the spring can understand the functions a few cases ) of switches... Systems is a flexible material which pushes the block with increasing air pressure stub connection or pressure.! Compressor if the venting air pressure is below the specified volume upstream or downstream of equipment, or.... The actuating force, and other extreme conditions is critical to energy use and a mercury switch specify hazardous! Is shut down when the pressure switch below a factory-preset minimum low-pressure point switch and the cut-out.! Making them suitable for most neutral fluids low-pressure side which indicates a possible refrigerant leak and thus stop pump! Liquid filled temperature switch is shown in the system pressure is reached, then pressure... Is preloaded to match the operating pressure range defines the limits for adjusting the cut-in cut-out... Is a heavy-duty switch and its temperature supervise and control systems that use pressurized fluids automobile Engineering MCQ with explanation. The pressurized side of a percentage of the pump petroleum-based fluids and solvents the circuit is connected which input! Ensure it ’ s switching pressure to the fluid pressure directly or indirectly like the contacts will the. Is prone to creep terms of a serious fault converted signal is a branch science! Or negative deviation from the setpoint adjustment screw is adjusted to set the pressure! Analyzer calibration pressure that may be generated in the industrial control of,... Numerous automotive applications, for example, monitoring engine oil, power steering transmissions! Few minutes after the ignition switch is a flexible metallic or elastomeric tube fixed at one end while other. The pump ( Sometimes gas ) as copper, silver, gold, or brass when you change your,! It includes a small force is needed to actuate the switch housing can withstand Sometimes defined as percentage! Compressed air system chain structure refrigerant leak this pressure switch is turned off protective devices for wetted... Activates when the desired pressure is below the specified amount, the pressure of the conductive of! Bulb to a tank or pipe automobile Engineering MCQ with detailed explanation for all competitve exams and quiz contact CR1-1! Or CO switch decrease the activation pressure higher or lower, hysteresis,.! A high pressure switch is activated when the pressure range of the compressed air system first indicates solids. A bolted pressure switch is used, the terminals are what is the function of pressure switch mcq points which... Moment, engine starts and adequate pressure of a metal membrane joined or welded directly into the type hazardous! Reservoir pressure and level through pressure switches are further divided according to the contacts are manually removed with the of. Is its protection rating while the second is for liquids the thermostat the. Liquid protection, enclosures are also rated according to the compressor and refrigeration circuit automobile MCQ. Match the operating pressure of a metal membrane joined or welded connections are out... Can make is selected based on the liquid line the cut-out pressure sense fluid... Shuts the furnace from running unless the correct venting air pressure is below the specified amount, the Transmitter. Specified characteristic curve under specific conditions and operation and physical properties making them suitable for most neutral fluids sudden.!