What are the General types of current transformers?
Current transformer are used for measuring current in a bus bar without disconnecting it by means of ammeter.There are three types
1.bar type current transformer
2.toroidal current transformer
3.wound type current transformer
Power transformer, Distribution Transformer. Current Transformer, Potential Transformer, Auto Transformer etc.
CURRENT TRANSFORMERS ARE BROADLY CLASSIFIED ASRING TYPE CTs : A CT which has an opening in the center to accommodate a primary conductor (busbar or cable) through it.BAR -PRIMARY CTs A CT in which the primary winding consists of bar of suitable size and, material forming an integral part of the CT.WOUND TYPE CTs : A CT having a primary winding of more than ane full turn wound on the core.Ring type (or rectangular type)… Read More
What is the advantage of 1 amps current transformer than that of the old type 5 amps current transformer?
If the protection relay and CT installed for away, then it is advised to install 1A CT rather than 5A CT. Because of lower amps it will reduce the losses on the cable. p = i^2.R
What are the functions of current transformers and the difference between current transformers and voltage transformers?
To sense the current flow across the current transformers and to monitor the current ratings. In current transformers no voltage variations occurs. but in voltage transformers it is mainly used to increase or decrease the voltage value.
A one to one, i.e. isolation, transformer. Comment It might be worth pointing out that the secondary current is determined by the load, and the primary current is then determined by the secondary current. The questioner appears to think that the secondary current is determined by the primary current.
Current transformers are used to monitor the current flow through larger diameter wires. They are rated in ratio of 1: to the ampacity of the wire they are monitoring. They are used in electrical distribution services over 200 amps. Maximum current produced is 5 amps. eg. A conductor has a maximum capacity of 500A and you want to see how much current is going through the wire at any one time. You have a meter… Read More
Measurements of electric currents AnswerA current transformer allows high values of a.c. current to be measured using an ammeter designed to measure lower-values of a.c. current. At the same time, it electrically isolates the primary circuit from the secondary circuit -essential if the primary circuit is part of a high-voltage system. CTs are also used to monitor primary currents for the operation of high-voltage protection relays.
These are used with low range ammeters to measure current in HVAC 's where direct connection of instruments is impratical. They not only insulate the instruments from HV lines but also step down current in a known ratio. ( i .e . ) Iline =(I1 \I2) * Ammeter Reading where Iline = Line Current I1 \I2 = Current Ratio
DC current cannot be used in a transformer only AC will work. A transformer needs the continual build and collapse of the magnetic field to keep the iron core from reaching saturation. Only alternating current will transfer power through a transformer.
As a transformer requires an alternating magnetic flux within its core, then the current flowing in its primary winding must be alternating.
Current transformer is measured a positive current flow. we used in neutral ct for measure the unbalance load
There are two type of transformers according to construction; 1- Core type2- Shell type
Secondry of CT should never kept open during functioning
A CT allows: heavy currents to be measured using conventional ammeters, and electrically-isolates the ammeters from high-voltage primary circuits.
The current transformer is used to measure the line current special transformer. Direct measurement of the current large and small need to range from a few security until tens of thousands of security many ammeter. This gives the instrument manufacture a great deal of difficulty. In addition, some lines are high voltage, direct electricity meter to measure the current of the power lines on the road is extremely dangerous. The current transformer is used to… Read More
Both Current and Potential Transformer are instrument Transformers which are used to measure very high current and voltage respectivly. Current Transformer is a Step up transformer and used to measure high current, its secondry is connected to ammeter of very small capacity (usally 5 A) but its Scale is calibrated according to actul values. Potential Transformer is a step down tansformer and its secondry is connected to voltmeter of small range but again the scale… Read More
kittys a w____R and so are you :)
The enclosure that houses winding in other words the tank is at line potential while in the other case it is at earth potential. it is the same in case of circuit breakers too.From NK Sharath Kumarcell 93412 55090res fax 080 22290151,l/l 080 22233669,firstname.lastname@example.orgWith live tank circuit breakers, the enclosure that houses the contacts is energized, ie. "live". Dead tank circuit breaker's contact enclosures are not energized and are connected to the ground grid. Live… Read More
Current tranformers transform amps(current) and usually have ratios of 100/1 or 2400/1. They come in different classes and accuracy factors depending on the application which can be for instrumentation or protection. Voltage transformers transform voltage. Either up, like at power stations for transmission to distribution, or down, like your cellphone charger from your house supply to the low voltage your cellphone needs. Ratios are for example 6600/400 Volts or 110/12 Volts. they also come in… Read More
This depends on the voltage, and whether it is a three phase or single phase transformer.
Current transformers are found in power generation, electricity transmission & distribution, railways, industrial equipment, vessel propulsion, wind & solar renewables applications. In each application layer there are a number of sub-application levels for current transformers; for example, accurate measurement of power, protection of electrical plant, differential protection, restricted earth fault, isolated phase busduct, interposing, and summation.
Compared with what?
CTs, as well as potential transformers, are called instrument transformers. If the current in the circuit is high then CT will reduce the current and produce a accurately proportional current required in the circuit.It is commonly used in metering systems,protective relays. AnswerA CT also has the important function of electrically-isolating the secondary circuit from the primary circuit -very important in high-voltage applications.
CT together with a ammeter is used to measure the current in high current or high voltage circuit, where a normal ammeter can not be connected in series in such high voltage or high current circuits. It is a secondary winding (like in transformer) wound on a single core primary wire and relative secondary current reperesnets the primary current. CT are also used protection purposes. Basic principle of CT i same either for metring or… Read More
Two types of instrument transformer are there.1. current transformer (CT)2. pottential transformer (PT/VT)
The two general categories of transformer, based on their construction, are (a) mutual transformers and (b) autotransformers. Mutual transformers have two coils, or 'windings', termed the primary (input side) and the secondary (output side), which are electrically isolated from each other, being linked with a magnetic field. Autotransformers have a single, shared, winding and so, do not provide isolation between the primary and secondary sides. Mutual transformers can be further classified, according to their function… Read More
A small list of transformers 1. Distribution Transformers 2. Padmount Transformers 3. Station Transformers 4. Station Transformers Various specific electrical application designs require a variety of transformer types. Although they all share the basic characteristic transformer principles, they are customize in construction or electrical properties for certain installation requirements or circuit conditions. Autotransformer: Transformer in which part of the winding is common to both primary and secondary circuits. Capacitor voltage transformer: Transformer in which capacitor… Read More
It is known that the value of transformation ratio (actual ratio) is not equal to the turns ratio in current transformers. Also the value is not constant, but depends upon the magnetizing and loss components of the exciting current, the secondary winding load current and its power factor. This means that the secondary winding current is not a constant fraction of the primary winding current but depends upon the factors listed above.
Primary winding carry more current. We measure the current in one single wire, so no of turns are 1, in secondary the no of turns are higher. so, obviously it has higher voltage then this wire. so, finally as per the transformer rule the secondary carry lesser current than primary.
A current transformer doesn't 'measure current'. It merely reduces a large current flowing through its primary to a smaller current which can be read by an ammeter connected to its secondary. At the same time, it electrically isolates the secondary circuit from the primary circuit, which is essential if the primary circuit is part of a high-voltage system.
The current rating of transformers vary widely as well as the types (step-down, etc.....). So depending on the use, the primary power, and the secondary power, the amp load will change. More in general current is amps, if your transformer has say 1Kva on it then that tells you the apparent power the transformer can handle. As a side note a lot of transformers are rated in VA or KVA and that is a combination… Read More
The burden on a CT is the sum total impedance connected to the secondary - including the CT secondary winding coil resistance, lead resistance, and any loads attached (relays, meters, etc.). If this is for power calculations and CT saturation in three phase systems, remember you must multiply the lead resistance by two to get the total path resistance. Another Answer We use the word, 'burden', to describe the load supplied by the instrument transformer's… Read More
why does have to short-circuit secondary wire of current transformer ?
Saturation describes the condition when a magnetic circuit (e.g. the core of the CT) reaches its maximum flux density (B). Any further increase in its magnetic field strength (H) will have no effect on the flux density. Since magnetic field strength is directly proportional to the current flowing through the primary winding, once saturation is reached, the CT's secondary current will no longer be proportional to the primary current.
it means accuracy class of CT. 5 p means 5 % of composite error will happen till 20 times of current is applied . So CT will follow its rated characterstics upto 20 times current Read more: http://wiki.answers.com/Q/What_does_mean_by_5p20_CT#ixzz1y7TvG5GB
Instrument current transformer is used to adjust the output voltage from power source to be conveniently used by instrument. Measuring current transformer is used to measure AC currents.
I am aware that Class TPS current transformers have a Low Leakage Flux design
A 'bushing' is a hollow insulator. It allows an energised conductor to pass through components operating at different potentials. In the case of a current transformer, it provides the insulation between a 'bar' primary and the secondary windings.
The CT's primary is inserted in series with the load. It's secondary is connected directly to the burden (e.g. ammeter). If used together with a VT (PT) for the purpose of measuring power or energy, then its polarity markings must be observed.
This is the current level needed to energize a transformer to its rated voltageThe clue is in the name! 'Excitation' means to create a magnetic field. So the excitation current is the current drawn from the supply which sets up the magnetic field around the core.
You need to know the Primary and secondary voltages to do the calculation. we only have 100Kva transformers on our salt furnaces as an example: 100000va / 12v = 8333 amps the secondaries , wire, and electrodes are water cooled.
1. Center Type Transformer 2. Shell-Type Transformer
* on-load tap changer * off-load tap changer
open circuit & short circuit test, insulation resistance test, turns ratio, efficiency, if it is oil cooled then breakdown voltage of oil, voltage regulation and definitely visual inpection...
The main application for a core type transformer is to increase voltage from a standard 240v supply up to 415v instead of using a 3 phase supply.
what are main safety in 33 kv transformer oil
The winding of this type of transformer are made up of concentric coils. These coils are round, some being very small and other being larger, some have an open hole in the centre, making them shaped like a flattened donut, and some are solid. A few of the manufacturers have migrated into designing their concentric coils into a design which has caused them to be referred to as "spider coils" because the bracing of the… Read More
Current transformers (CTs) -together with voltage (or potential) transformers- are 'instrument transformers'. CTs are used to enable large currents flowing in high-voltage systems to be measured, while electrically-isolating the ammeter (termed a 'burden') from the h.v. system. They are also used to monitor h.v. currents for high-voltage protection systems. Before disconnecting its burden, the secondary of a CT must be short-circuited, and remain short-circuited until after the burden has been replaced. This is because a… Read More
A current transformer is a donut (toroidal) shaped transformer. You use it to measure current (expressed in amperes). You run your wire to be measured through the transformer and it produces a variable output based on the current. A potential transformer is basically a high ratio transformer that is used to measure voltage on high-voltage lines. For example: They will use a 10:1 ratio potential transformer to convert 4160v to 416v. Then they can measure… Read More