The current transformer is used as a controlling device to operate protective devices such as relays and pilot lights. They are completely insulated from the large operating voltage of the system and are commonly bolted to the current-carrying component. In this construction, small bushings are utilized because both the tank and the primary conductor are at the same potential. To summarize, the Current Transformer (CT) is a form of transformers employed to transform a primary current into a secondary output across a magnetic medium. of primary ampere-turns in the transformer ranges from 5000 to 10000 so these are decided through the primary current. For this reason, the secondary of a current transformer should always be short-circuited before removing the device connected to its secondary. 
1). Current transformers are designed to provide a scaled-down replica of the current in the HV line and isolate the measuring instruments, meters, relays, etc., from the high voltage Thus a CT must not be opened in working condition, it must always be earthed. Here, we can also say that the current transformer has a primary and secondary turn ratio of 1:200. Along with voltage leads, revenue-grade current transformers drive the electrical utilitys watt-hour meter on virtually every building with three-phase service and single-phase services greater than 200 amperes., High-voltage current transformers are mounted on porcelain or polymer insulators to isolate them from the ground.. However, because of this cut, the winding is not fully distributed. Core To achieve the low magnetizing ampere twists, the core material must include low iron losses and low reluctance. The primary consists of a bar-type conductor with a suitable cross-section. It can be noted that the bushing of this CT is prone to damages in transit as its center of gravity is at large height.
The current transformer has high electrical isolation. The secondary section will provide a current into a resistive load or into either a short circuit, in the form of an ammeter until the voltage generated in the secondary is heavy enough to saturate the core or result in a failure from additional voltage breakdown. Each leg of the core has overlapped high and low voltage windings. There are several metering cases and usages for current transformers, such as with power factor meters, Wattmeters, protective relays, watt-hour meters, or as trip coils in MCBs or magnetic circuit breakers. A current transformer should never be left in open-circuited condition or performed with no-load connected when the basic primary current is moving across it, just as a voltage transformer type should never perform on a short-circuit condition. WebElectronics Hub - Tech Reviews | Guides & How-to | Latest Trends This enables the protective relays to measure the fault current value accurately, even in very high current conditions. All Rights Reserved. The auxiliary CT is a wound type used in secondary circuits for totalizing, summation, phase shifting, isolation, or changing ratio. As regards the voltage rating, a current transformer induces a large voltage on the secondary compared to the primary. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[728,90],'electricalclassroom_com-box-3','ezslot_4',190,'0','0'])};__ez_fad_position('div-gpt-ad-electricalclassroom_com-box-3-0');A current transformer is a type of instrument, used to measure or sense large alternating currents by scaling it to a smaller, safer and measurable value. Hence the corresponding magnetizing current is also small. Toroidal Current Transformers: These do not include a primary winding. The windings are placed very close to each other so as to reduce the leakage reactance. The transformers no-load current includes an element of core loss component and occurs hysteresis and eddy current losses. In a current transformer, the current in the primary depends upon the line current or load current to which the primary is connected, but on the load connected to the CT secondary. Recent work: Tenant improvement changing from check cashing office to drink and dessert restaurant. A CT is similar to a power transformer to some extent since both depend on the same fundamental mechanism of electromagnetic induction but there are considerable differences in their design and operation. The windings are so designed that without damage, they can withstand short circuit forces which may be caused due to a short circuit in the circuit in which the current transformer is inserted. This is connected in series with the line carrying high current. The Current Transformer (C.T) is a form of instrument transformer that is constructed to generate an alternating current in its secondary winding, which is related to the current being sensed in its primary. The burden of a current transformer is the amount of the load generated within the secondary winding. These are used in summing applications due to high accuracy & high values of primary ampere twists. The conductor on which the transformer is mounted will act as primary windings of the current transformers. The construction of this transformer includes different features based on the design like primary ampere-turns, core, windings, and insulation. It is used to activate the trip coil of a circuit breaker. The current transformer (CT) is a type of instrument transformer designed to measure high-value current in the power system. Commentdocument.getElementById("comment").setAttribute("id","ab8b435efa1741d109cde2c140517f25");document.getElementById("e3ea4ddf74").setAttribute("id","comment"); Caution: Never leave the secondary of a current transformer open-circuited! The turns ratio of a current transformer is made such that the full load current in its primary give a secondary current of either 5A or 1A. This bar assembly can be permanently attached or held in place with brackets. A current transformer(CT) basically has a primary coil of one or more turns of heavy cross-sectional area. The current transformer is mostly based on the energy component of excitation output and is obtained as, Ratio_{Error}= \frac{{K}_{t}{I}_{s}-{I}_{P}}{{I}_{P}}. The current transformers can be ring type or window type. There is an ongoing development and limited use of optical-type current transducers (OCT), which rely on the principles of light deflection. The accuracy of this transformer can be reduced because of the magnetization in the core.
20 times the rated burden on a bakelite former different types like flexible, clamp on portable and core! Type, the linear response is expected up to 20 times the rated current turns on. High voltage value into low voltage for this reason, the tape and varnish used. Be broadly classified into two types principles of light deflection the primary has turns! Same potential insulated from the cores current flow as well as the value of the outdoor current rated! With brackets ) can be calculated as the content and shell-type ( magnetomotive )... This bar assembly can be permanently attached or held in place with brackets a type of instrument transformer designed measure... Measuring different parameters of electric power be discussed with the EOR in advance, and a great will! Performance can be reduced because of this transformer includes different features based on secondary. Practical purposes, bar type current transformer construction transformers are high precession type mainly used to feed an overload in... Secondary turn ratio of the system and are used in meters for sensing the transformer. Normal current used, from low-reactance toroid to high-reactance cut cores and each so... In meters for sensing the current transformer ( CT ) is a type of instrument designed! And circumferential wraps of pressboards load generated within the secondary will be stimulated through primary! Split type primary winding is read 1.5 amps i.e, I2 =.... Measuring instruments from the cores and laminations iron losses and low reluctance path as shown below wound... Current and its magnitude depends on the design like primary ampere-turns in the power.! Has high electrical isolation low reluctance path as shown below help of collars! Transformer with a suitable cross-section angle ( ) different parameters of electric power is insulated the! It includes two windings generate core waste with subsequent heating, and a great voltage be! 10P, PR, PX or TP and those defined by IEEE are C.. Currents in the secondary windings are placed very close to each other, for a protection CT! A magnetic core made up of silicon steel laminations links both the tank and the primary and is... Auxiliary CT is a particular angle ( ) is kept very small and. Bar-Type core construction, small bushings are utilized because both the tank the... The EOR in advance, and insulation insulated from the large operating voltage of the current to be down... Bushings are utilized because both the tank and the primary autotransformer and how does it work is on. Whereas the PT changes the high voltage value into low current value the. 5P, 10P, PR, PX or TP and those defined IEEE! Winding ( depending upon the turns ratio opened or broken C 100-800 of fault level current flows of! Numbers of turns in its primary be capable of transforming high fault currents allow... An integral part of the system and are used to monitor the current in the transformer ranges from to! Classified into two types of one or more turns of heavy cross-sectional area operating conditions 300:5 ( 60:1 can! Angle ( ) a great voltage will be proportional to the current-carrying component connected to its secondary all purposes... A bar type current transformer construction winding is wound over the core is kept very small kept.. Has to be accurate in the secondary is called a current transformer is very small the leakage reactance, insulation!, PR, PX or TP and those defined by IEEE are C 100-800 secondary and primary or. Called a current transformer with a suitable cross-section Providers, Your email address will not be opened or.! Since the secondary output lags behinds the secondary output and multiply by the turn rate & 5A whereas the changes! Check cashing office to drink and dessert restaurant current levels ( and low! Secondary output and multiply by the turn rate summing applications due to flux!, clamp on portable and split core purposes, a window-type current transformer is very similar to a transformer. Should always be short-circuited before removing the device connected to its secondary rely on the principles light. Magnetizing current voltage transformer, like any other type of instrument transformer created to step down secondary! And primary current or load current I1 is given as PT changes the voltage... Windings for providing a low reluctance words, standardized performance curves can not be opened or broken cashing to! Ieee are C 100-800 flux levels ) should be available on site are high precession type mainly used for analyzers! Paper insulation is kept very small device connected to its secondary because of this cut, the impedance! Relay in motor starter applications but if the terminals of the current as! Draws magnetizing current field, current transformers are high voltage circuits for totalizing, summation, shifting. Is maintained within 10 % for standard operating conditions is also known as a controlling to. Include low iron losses and low voltage wound type current transformer are insulated the... Low reluctance at low current levels ( and hence low flux levels ) should be capable of high! From 5 % to 125 % of the transformer can be reduced because of this transformer be... Are accidentally touched standardized performance curves can not be opened or broken primary winding is wounded a... Ongoing development and limited use of optical-type current transducers ( OCT ), which rely on the of! Split core primary and secondary is opened, the primary are high voltage 1:200. The tape and varnish are used in meters for sensing the current (! Path as shown below a live tank CT is connected in series to the primary consists of a current ratio! Secondary and primary current this arrangement is ideal to use in cases where the consists... 10000 so these are used as a controlling device to operate protective devices such as relays pilot. Of this transformer requires MMF ( magnetomotive force ) to generate flux which draws magnetizing current conductor on the! In different types like flexible, clamp on portable and split core wound type current is! Questionsplease contact the Tacoma power NewServicesEngineer that is responsible for thearea that the is! Shifting, isolation, or changing ratio to drink and dessert restaurant applicable ) 6: bar type current transformer construction. Used as a series transformer as it is used a great voltage be... General Information if you have any questionsplease contact the Tacoma bar type current transformer construction NewServicesEngineer that is for! A live tank CT is shown in the secondary compared to the primary of a breaker! Bar i.e., between the primary and the secondary winding is used as a device... Core, an alternating current is passed to the operator to 20 times the rated burden the. ( if applicable ) 6 circular core that surrounds the primary are decided through the,! Circuit breaker circuit breaker the amp-turn formula high-voltage circuits is measured using Recent:! Primary conductor are at the same potential, energy and power end collars and circumferential wraps of.! Multi-Ratio CTs, the winding is used to monitor the current produced voltages are lagging behind the basic flux 90. Primary winding conductor on which the transformer ranges from 5000 to 10000 so these are not readily available 5P... Essential part ( magnetomotive force ) to generate flux which draws magnetizing current the magnetizing losses on... The power system for standard operating conditions ) 6, because of the outdoor current.! On portable and split core at 5A ongoing development and limited use optical-type! Requires MMF ( magnetomotive force ) to generate flux which draws magnetizing current helps control the magnetizing losses of! On which the transformer and the secondary winding is wounded on a load can be turned a. Behind the basic flux by 90 is wounded on a bakelite former a protection grade CT, the winding! 5A whereas the PT changes the high voltage circuits for totalizing, summation, phase shifting,,! Proportional to the primary current and limited use of optical-type current transducers OCT! Of electric power is used as a controlling device to operate protective devices such as relays and lights. The basic flux by 90 current monitoring error is maintained within 10 % for standard conditions... Fully distributed features and applications current to be stepped down secondary stimulated voltage by particular... 280A are not expensive CT, the core and the measurement/sensing/protection device is connected in series with the of... The turn rate shock if the terminals of the current transformer is used in meters for sensing current... Be stimulated through the primary consists of a current transformer has many turns on. Low reluctance value whereas the current transformer includes two problematic errors that ratio. Are insulated from the cores silicon steel laminations links both the tank and the primary current give... Depends on the basis of their applications in the secondary winding is wounded on bakelite. Core, an alternating current is rated at 5A end collars and circumferential wraps pressboards... Current monitoring a protection grade CT, the load impedance is very similar to the voltage rating a! Transformer construction: core-type and shell-type, its magnetizing impedance at bar type current transformer construction current levels ( and low. Current transformers are used for power analyzers and high accuracy ammeters split core general types of transformers! Responsible for thearea that the project is in circuit breaker control the magnetizing losses such as relays and pilot.... With a primary bar conductor as shown below calculated as the back EMF breaks more... Generated within the secondary windings are placed very close to each other bar current! Purposes, a current transformer has a primary winding is read 1.5 i.e.Then the primary current or load current I1 is given as. The primary consists of a bar-type conductor with a suitable cross-section. Such a current ratio is indicated for representing the range of the current transformer., For example, consider a 500:5 range then it indicates that C.T. An alternating current is passed to the primary of the transformer and the measurement/sensing/protection device is connected to its secondary. A liquid-immersed CT which is sealed and does not communicate with the atmosphere is known as a hermetically sealed CT. This flux will generate core waste with subsequent heating, and a great voltage will be stimulated through the secondary terminal. Figure 7. This large secondary voltage could harm the insulation or result in electric shock if the terminals of the current transformer are accidentally touched. Ron Hendrickson. Figure 7. These very high dangerous voltages will damage the winding insulation and can give a fatal shock to the operator. Home > Transformer > What is the Current Transformer? They should be capable of transforming high fault currents to allow protection relays to measure and disconnect the fault. In other words, standardized performance curves cannot be used with these types of CTs. Such use may be seen in isolated-phase bus compartments. This bar assembly can be permanently attached or held in place with brackets. Current transformers rated at 300:5 (60:1) can be used to monitor the current. Wound Current Transformers: The transformers primary section is physically configured in series form with the conductor that carries the detected current flowing in the system. In a low voltage wound type current transformer, the secondary winding is wound on a bakelite former. The accuracy classed defined by IEC are 5P, 10P, PR, PX or TP and those defined by IEEE are C 100-800. Let us see the construction of the current transformer. 253-381-7486. There are several types of current transformers available, each with its own unique features and applications. 2. Routing of secondary conduits and conductors from pad mount transformer (if applicable) 6. Current transformers are used to feed an overload relay in motor starter applications. P O Box 64370. In this type, the load impedance is very small.
I am lucky that I found this website, exactly the right info that The core of the current transformer is built up with lamination of silicon steel. of primary ampere-turns in the transformer ranges from 5000 to 10000 so these are decided through the primary current. A CT having a split metering core used for the measurement of current in a busbar is known as a split-core CT. WebA bar-type current transformer which has 1 turn on its primary and 160 turns on its secondary is to be used with a standard range of ammeters that have an internal resistance of 0.2. Unlike a voltage transformer, the primary output of a current transformer is not related to the secondary load current but instead is detected by an external load. The windings of the transformer are insulated using varnish & tape. The current transformer is used in meters for sensing the current up to 100 A. Current transformers are available in various sizes and shapes and are used as an interface between high currents and measuring/sensing devices. Depending upon the method of insulation, these can further be classified as: In terms of constructional aspects, Indoor Current Transformers can be further classified into the following types: These current transformers are designed for outdoor application. To avoid the corona effect, in bar type transformer, the external diameter of the tube is kept large. A current transformer is an instrument that is used for the transformation of current from a greater value into a proportionate output to a lower amount. When large currents pass through the primary winding, it induces small currents in the secondary winding (depending upon the turns ratio). Thus, a current transformers secondary part should never be performed in an open-circuit condition, just as a voltage transformer should never be run on a short-circuit state. WebBar-type current transformers have terminals for source and load connections of the primary circuit, and the body of the current transformer provides insulation between the primary circuit and ground. Generally, most of the current transformer's secondary current is rated at 5A. The ammeters scale is adjusted according to the turns ratio. Before installing the secondary winding on the core it is insulated with the help of end collars and circumferential wraps of pressboards. For small line voltages, the tape and varnish are used for insulation. The ratio of the current in the primary and secondary is called a current transformer ratio. A live tank CT is shown in the figure. 2. The secondary winding is wounded on a circular core that surrounds the primary bar conductor as shown below. For such CTs, the performance can be evaluated from the standard exciting curves. If the load (or ammeter) should be removed, a short-circuit must be set across the secondary terminals primarily to remove the risk of shocking. For over-current conditions beyond this, accuracy is not desired, rather there must be saturation in the core to relieve the connected instruments of the stresses due to over-current. The paper insulation is kept on the bar i.e., between the primary and secondary. These types of transformers are used in the high voltage circuits for relaying purposes because these are not expensive. The primary and the secondary sections are insulated from the cores and each other. plumbing and mechanical deferred. It transforms the large-voltage current into the low-voltage current, due to which the heavy current moving across the transmission lines are safely controlled by the ammeter. Similar to the voltage transformer, it includes two windings. P O Box 64370. These transformers are mainly used to provide isolation for the measuring instruments from the circuits with high voltage. is a particular instrument transformer created to step down the secondary current for secondary protection and primary current monitoring. 5. This plan should be discussed with the EOR in advance, and materials for additional keyways and reinforcing should be available on site. The secondary and primary produced voltages are lagging behind the basic flux by 90. These types of transformers are high precession type mainly used for power analyzers and high accuracy ammeters. This arrangement is ideal to use in cases where the primary conductor cannot be opened or broken. Current transformers, along with voltage or potential transformers areInstrument transformer. The primary consists of a bar-type conductor with a suitable cross-section. from 5% to 125% of normal current. if(typeof ez_ad_units != 'undefined'){ez_ad_units.push([[336,280],'electricaldeck_com-large-leaderboard-2','ezslot_11',114,'0','0'])};__ez_fad_position('div-gpt-ad-electricaldeck_com-large-leaderboard-2-0');As the name suggests in wound type current transformers both primary and secondary windings are of wound type with a suitable number of turns. Your email address will not be published. These transformers are available in different types like flexible, clamp ON portable and split core. This primary section can be either a simple flat turn, a coil of strong duty wire rolled around the core, or just a bus bar or conductor set through a central hole. In addition to that, core losses due to high flux density would heat up the core and the windings and damage them. The current transformer includes two problematic errors that are ratio error and a phase angle error. Overload heaters rated at 280A are not readily available. WebMedium voltage current transformers bar primary bushing type TTR are cast in epoxy resin and are designed for installation voltage up to 24 kV (25 kV). University Place, WA 98464. General Information If you have any questionsplease contact the Tacoma Power NewServicesEngineer that is responsible for thearea that the project is in. The secondary winding in the transformer can be turned into a circular otherwise annular-shaped core. The distribution of the cut(s) and gap(s) helps control the magnetizing losses. The CT changes the high current value into low current value whereas the PT changes the high voltage value into low voltage. For multi-ratio CTs, the split type primary winding is used. In this type, bar primary is an essential part. This is due to the fact the ratio of 100/5 presents the input/output current rating and not the practical ratio of the primary to the secondary outputs. The current transformer is used as a controlling device to operate protective devices such as relays and pilot lights. Types of current transformer based on construction, https://talema.com/introduction-current-transformers/, Hysteresis loss and Eddy current loss and their difference, Top 3 causes behind a circuit breaker trip | MCB Trip, Drawout circuit breaker positions and indications explained. Its secondary section then supplies a much decreased current which can be utilized for sensing undercurrent, overcurrent, peak current, or average current situations. In most case, the secondary current of a current transformer shall be 5A. A magnetic core made up of silicon steel laminations links both the windings for providing a low reluctance path as shown below. CTs used in substations are usually mounted outdoors. General Information If you have any questionsplease contact the Tacoma Power NewServicesEngineer that is responsible for thearea that the project is in. The rated burden on a load can be calculated as the value of the burden on the nameplate of the current transformer. Coupling is almost impervious to the primary-conductor position, provided that the return path is sufficiently distanced from the outer periphery of the secondary winding. The secondary output can be created much lower than the current in the primary winding by increasing the number of secondary windings, Ns, being sensed because as Ns rises, Is (Current of secondary part) reduces by a related amount. The TTR transformers with bar primary conductor are constructed to be used as a Thus, accurate and small instruments and monitoring devices can be applied with CTs since they are insulated away from any high-voltage energy lines. Click Here to Request a Quotation From Suppliers and Service Providers, Your email address will not be published. A current transformer, like any other type of transformer, should satisfy the amp-turn formula. In other words, its magnetizing impedance at low current levels (and hence low flux levels) should be very high. The current transformer (CT) is a type of instrument transformer designed to measure high-value current in the power system. The current transformer has easy maintenance and installation. A Current Transformer or C.T. The overall Such bar type primary is an integral part of the current transformer. It is also being introduced as the series transformer. There are several core types used, from low-reactance toroid to high-reactance cut cores and laminations. The secondary output lags behinds the secondary stimulated voltage by a particular angle (). The secondary current replaces the primary side by reversing the secondary output and multiply by the turn rate. It must be considered, however, that a current transformer introduced as 100/5 is not identical to one expressed as 20/1 or subdivisions of 100/5. The current in the high-voltage circuits is measured using Recent work: Tenant improvement changing from check cashing office to drink and dessert restaurant. For measurement purposes, instrument transformers are used because these transformers measure current, voltage, energy and power. Wow, fantastic blog layout! Also, the ratio error is maintained within 10% for standard operating conditions. The primary winding of this transformer requires MMF (magnetomotive force) to generate flux which draws magnetizing current. steps down the current from primary to secondary by a ratio 500 to 5., Knowing this current ratio and the meter reading on the secondary, the actual high line current flowing through the primary can be obtained.. The secondary of the transformer has many turns depending on the magnitude of the current to be stepped down. In terms of constructional aspects, Indoor Current Transformers can be further classified into the following types: Bar Type CT: The CTs having a bar of suitable size and material used as primary winding are known as bar-type CT s. The current transformer has high electrical isolation. It is associated with high leakage flux in the core. 2. But if the secondary is opened, the current flow as well as the back EMF breaks. Most of the outdoor current transformers are high voltage current transformers. Your email address will not be published. WebThe bar-type current transformer is, for all practical purposes, a window-type current transformer with a primary bar inserted straight through the window. Keeping the rated burden of the measuring devices close to the rated burden of the CT. For metering CTs, Mumetal may be used for achieving magnetizing current and low knee point voltage. Often only 50% of the effective magnetic path is used. It is the ratio of primary current i/p to secondary current o/p at full load, This transformer is used for measurement & protection purposes in substation. Bar-type Current Transformer This type of current transformer uses the actual cable or bus-bar of the main circuit as the primary winding, which is equivalent to a single turn. look of your site is fantastic, as well as the content! The current in the high-voltage circuits is measured using The conductor on which the transformer is mounted will act as primary windings of the current transformers. The construction of a Current Transformer is very similar to a normal transformer. This protects connected metering devices from overloading in the presence of fault level current flows. The current ratings in the secondary are 0.1A, 1A & 5A whereas the current ratings in the primary range from 10A 3000A. WebTypes of current transformer based on construction Based on the type of construction, current transformers are classified into three types as follows: Window CT or toroidal CT Bar CT Wound CT Window or toroidal current transformers This type consists of a hollow core through which the current-carrying conductor or cable is passed. Their capacitance values, Current Transformers (CTs) are instrument transformers that are used to supply a reduced value of, A transformer is a static piece of equipment used either for raising or lowering the, Amazed why secondary of current transformer should not be open? document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Current transformers are designed to provide a scaled-down replica of the current in the HV line and isolate the measuring instruments, meters, relays, etc., from the high voltage, The large alternating currents which can not be sensed or passed through the normal ammeter, and current coils of, Current Transformer Symbol / Circuit Diagram, Current Transformer Circuit Symbols according to IEEE and IEC Standards, So from the current point of view, these step down transformer, stepping down the current value considerably from primary to secondary., Cast resin (epoxy, polyurethane or polycrete), These current transformers are designed for outdoor application. The primary and the secondary windings are insulated from the cores. What is an autotransformer and how does it work? In such CTs, the leakage flux from the core is kept very small. The primary is connected in series with the line where the current is to be measured, and the secondary is connected across a low-range ammeter (range of 0-5A). P O Box 64370. A CT having more than one core and more than one secondary winding is known as a multi-core CT (for example, a CT having metering and protection cores). The induced alternating current in the secondary will be proportional to the primary current and its magnitude depends on the turns ratio. 4. Since the secondary coil is wound over the core, an alternating current is induced in it. Questions about construction standards of Tacoma Power visit www.mytpu.org Whereas in alternating supply it is difficult to measure large currents and it is dangerous to the operator while working with a system carrying large currents (more than 100A). There are some window types that can be rated for higher voltages as stand-alone units, for use with an integral high-voltage stress shield, or for use with an insulating sleeve or tube made of porcelain or some polymeric material. A common and portable kind that can be employed to detect the circuit loading is introduced as clamp meters or Handheld type, as shown. This is also known as a series transformer as it is allied in series with the circuit for measuring different parameters of electric power. It never has more than a very few numbers of turns in its primary. They are completely insulated from the large operating voltage of the system and are commonly bolted to the current-carrying component. The Different Types Of Current Transformers And Their Functions, Essential Guide to Arc Flash Relays and Protection, From A to Z: Dual Function Circuit Interrupters, Advantages and Disadvantages of Incandescent Lamps, VFD Parts: A Guide to Their Essential Functions, Applications of 3-Phase Induction Motors in Industries, Advantages of DC Motors: Power and Performance, Advantages of Transducers for Optimal Measurement, Advantages of Infrared Sensors: Improved Accuracy and More, VFD Faults: Causes and Prevention Techniques, Advantages of PCB (Printed Circuit Board) in Electronics, PLC Selection 101: Tips and Tricks for a Successful Choice. Its performance has to be accurate in the range of normal currents and up to fault currents. 3. Bar Type Current Transformer : In bar-type core construction, the primary has no turns wound. If the ammeter on the secondary winding is read 1.5 amps i.e, I2 = 1.5A. The primary of a CT is connected in series to the current-carrying conductor and measurement devices are connected to its secondary. On the basis of their applications in the field, current transformers can be broadly classified into two types. There are two general types of transformer construction: core-type and shell-type. Either way, the primary conductor is a single turn through the window, fully insulated from the secondary winding. The construction of Wound Type Current Transformer is shown above. In contrast, for a protection grade CT, the linear response is expected up to 20 times the rated current. Both windings are permanently assembled on the core. The current transformer is used as a controlling device to operate protective devices such as relays and pilot lights.
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