Ct installation and wiring continental control systems, llc. The stbb991992 outdoor, square, windowtype current transformer is an 8. Window type application the psg981 indooroutdoor, generator current transformer ct is a 600 volt, 10 kv bil rated unit and designed to fit over a variety of specified generator bushing sizes. Current transformers,voltage transformers and instrument. Current transformers support type support window type. Current transformer ct inside diameter goes from 15 to 160mm. On window type units with low primary current ratings, where the primary conductor size is small, the ratio of the transformer can be changed by taking multiple wraps of the primary conductor through the window.
Less than 10% ratio error at 20 times rated current. Instrument transformer basic technical information and. The fuse is fitted directly on the primary conductor and the unprotected part of the measurement line is therefore very short. Galco industrial electronics is dedicated to providing worldclass control engineering solutions through the integration of high performance products such as fanuc fa america cncs, abb drives, control techniques, yaskawa and eaton automation. Instrument transformers scale the large values of voltage or current to small. These are developed using innovative techniques of production and flexible designs to ensure international quality standards, kalpa cts are widely known.
Mv indoor cast resin current transformers kalpa electrikal. The wound type provides excellent performance under a wide operating range. A selection guide is provided in this catalog to aid in selecting the type of ct for your application. The din rail current transformer comprises a terminal strip, current transformer and the voltage tap terminal with fuse. Accuct series splitcore cts open by squeezing the knurled panels to release the latch and pull rotate the top open. A wide variety of window type current transformer options are available to you, such as current, electronic, and instrument. Current transformers moulded in self extinguishing resin for the measure of ac currents from 50 up to 5000a.
The bushing type is typically used around the bushing on circuit breakers and. Metering toroidal current transformers traditional, window type current transformers for measuring 50400hz currents of 5a to 15000a with secondaries of 0. Typically, larger amounts of electricity require larger wires, so its important to keep window size in mind. The most common ct secondary full load current is 5 amps which matches the standard 5 amp full scale current rating of switchboard indicating devices, power metering equipment, and protective relays. A current transformer can also be used as an input to a current relay or transmitter, or to reduce the current so that a current switch or transducer can be utilized. The company behind the window type current transformer sadtem has developed its expertise in the production of the window type current transformer over more than 80 years, since being founded in 1929. The basics of current transformers nk technologies. The primary never has more than a very few turns, while the secondary may have a great many turns, depending upon how much the current must be stepped down. A transformer is an electrical device that can be used to transfer the power from one circuit and another circuit without physical contact and without changing its characteristics like frequency, phase. Model 276 series current transformers model 276a one. Current transformers ct are used in high voltage hv and medium voltage mv 1 installations to give an image of electrical current to protection relays and units and metering equipment and they are designed to provide a current in its secondary proportional to the current flowing in its primary.
By far, the most common one is the wound type current transformer. Current transformers support window type current transformers for indoor service, encapsulated in resin. The various types of transformer shown in the figure above are explained in detail below. Bar type current transformer the cable or bus bar of main circuit has been used in bar type current transformer as the primary winding.
Window type current transformers are also common, which can have circuit cables run through the middle of an opening in the core to provide a singleturn primary winding. They are fully insulated from the high operating voltage of the system and are usually bolted to the current carrying device. A current transformer ct is a type of transformer that is used to reduce or multiply an alternating current ac. The polarity marks of a current transformer indicate that when a primary current enters at the polarity mark h1 of the primary, a current in. The x1 secondary terminal is the polarity terminal figure 3. This drytype, solidcast current transformer will operate with high accuracy for metering or relay applications. Bartype current transformer this type of current transformer uses the actual cable or busbar of the main circuit as the primary winding, which is equivalent to a single turn. The current transformer will operate into either a short circuit or a resistive load until the voltage induced is enough to. For use with up to 8 gauge wire, and up to 40 amps on the primary. A window type current transformer is sometimes also known as a zero sequence current transformer or by the acronym, zsct. Know about different types of transformers and its uses transformer one of the oldest innovations in electrical engineering. The ip5 a ratio current transformer delivers at the secondary a current is. Instrument transformers are used for measurement and protective application, together with equipment such as meters and relays. Chapter 16 current transformer design university of north.
Selecting current transformers janitza electronics. Current transformers, along with voltage or potential transformers, are instrument transformers. This type of transformer is categorized on the basis of a number of turns in the primary and secondary windings and the induced emf. Continuous current rating factor test standard inside diameter outside diameter width height to centre of window mounting base plate body material indoor, bisa epoxy, red outdoor, cycloaliphotic epoxy, grey application low temperature below 5.
Another very common type of construction is the socalled window, through or donut type current transformer in which the core has an opening through which the conductor carrying the primary load current is passed. The stbb991992 outdoor, square, window type current transformer is an 8. We will manufacture window type current transformer for high voltageextra high voltage and for busbar at very low cost. We have ultraprecise current transformer for measurement of microscopiclarge 0. Nov 15, 2019 this type consists of a bar of suitable size and material forming an integral part of the transformer. Model 276a current transformer a low cost, openframe type current transformer ct. It is high operating voltage which has been bolted to current carrying device. Since the load current passes through primary windings in the ct, screw terminals are provided for the load and secondary conductors. Indoor cast resin current transformers upto 33kv system voltage. The primary winding may be a permanent part of the current transformer, i. This type consists of a bar of suitable size and material forming an integral part of the transformer. Model 276b current transformer a ringtype current transformer for currents from 50 to 1200.
Many times this is not possible because of critical loads. Windowtype current transformers are also common, which can have circuit cables run. The correct way to specify and install current transformers. This is not really a turn or wrap around the core but just a conductor or bus going through the window. The din rail current transformer is a highly compact special variant with integrated voltage tap. The current transformer window opening should be sized according to the outside diameter of the wire and the number of wires, with ample clearance added to facilitate installation. Current transformer construction types janitza electronics. Different types of transformers and their applications. Current transformer basics and the current transformer. Split core cts are available for measuring currents from 100 to 5000 amps, with. It is available in various dimensions and specifications to cater to the varied requirements of clients. Use the following formula for multiple wires of the same diameters through the current transformer window opening.
Current transformers product catalog search results. The kneepoint voltage is less applicable for metering current transformers as their accuracy is generally much tighter but constrained within a very small bandwidth of the current transformer rating, typically 1. Their role in electrical systems is of primary importance as they are a means of stepping down the current or voltage of a system to measurable values, such as 5a or 1a in the case of a current transformers or 110v or 100v in the case of a voltage transformer. Types of transformer different types of transformer. Based in douai in the nord department of france, the companys expertise and the quality of its product line has been recognised by the industry, resulting in an expansion that has seen the company grow to serve clients in more than 80 countries worldwide. A wide variety of open type current transformer options are available to you, such as current, potential, and electronic. A current transformer ct is a type of transformer that is used to reduce or multiply an. Place the ct around the conductor and rotate the top back to the closed position until the latch snaps closed. This drawing along with information and related documents may not be duplicated or released in whole or in part without written permission and is the exclusie property of olycast s s all dimensions in inches unless otherwise speciedc p polycast. Apr 16, 2011 the most common one is the wound type current transformer.
Cts with a 1 amp fullload value and matching instruments with a 1 amp full range value are also available. Window type current transformers for cable rs isolsec. Simply short the secondary of the ct through the sensing window of the sensor. This type has a primary winding of ore than one full turn wound over the core. Current transformers reduce high voltage currents to a much lower value and provide a convenient way of safely monitoring the. Typically, the wound type is insulated to only 600 volts. We use three types of current transformers that come in all sizes. The third part of the ct accuracy class is the maximum burden allowed for the ct. The primary of a current transformer typically has only one turn. Therefore, the current transformer does the current conversion from high currents to a measurable range of currents. Type psg981 generator current transformer indoor or outdoor instrument transformers product features.
Whilst measurement current transformers are intended to reach saturation point as quickly as possible once they exceed their operational current range expressed by the overcurrent factor fs in order to avoid an increase in the secondary current with a fault e. Standard types isiecansi window type current transformer. Notice m2fm with inner diameters from 200 to 400 mm, these transformers are often used on power transformers bushings or on generator bus bars. The secondary wind of the ct is placed around the current flowing conductor. Toroidal support type without primary conductor to be installed in medium voltage busbars without insulation. Primary current from 40 to 5000a reinforced insulation 0. Model 276b current transformer a ring type current transformer for currents from 50 to 1200. Three phase core type, power transformer 1 0 to 1 2 0. A current transformer can also be used as an input to a current relay or transmitter, or to reduce the current so that a current. Window type cts should be mounted with the h1 side of the window towards the power source. To correctly measure current, the ct has to be able to wrap around the entire conductor of the current being measured. The ct ratio is the ratio of primary current input to secondary current output at full load.
It produces a current in its secondary which is proportional to the current in its primary. You can also choose from three, single open type current transformer there are 1,027 suppliers who sells open type current transformer on, mainly located in asia. The current transformer function is different than that of a voltage transformer. Mar 07, 2017 to correctly measure current, the ct has to be able to wrap around the entire conductor of the current being measured. As a leading producer of medium voltage instrument transformers, sadtem manufactures this type of transformer in addition to other indoor and outdoor current transformers, voltage transformers for indoor and outdoor use, combine transformers and bushing type transformers. Jun 02, 2015 therefore, the current transformer does the current conversion from high currents to a measurable range of currents. The main role of current transformer for which it is highly known is providing the current adjusted according.
A wide variety of window type current transformer options are available to you, such as. C high pollution specifications o o window type current transformer shielded. A current transformer operates with a set primary current and will try to output a constant current to the load, independent of the load. Rs isolsec window type low voltage current transformers cts are designed for all kinds of low voltage applications where the primary cable passes through the transformer. The specific application of current transformers involves in various considerations such as type of mechanical construction, ratio of primary to secondary currents, type of insulation oil or dry type, thermal conditions. Model 276 series current transformers model 276a one primary turn. When circular coils are required for distribution and power transformers, the square and stepped cores are used. Basics, maintenance, and diagnostics vii contents continued page 4. Tape wound measuring and protection current transformers.