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General information on electrical transformers


General information on electrical transformers

* History of Transformers:
Faraday was first discovered in 1831 the phenomenon of mutual incitement between two separate files and present
At the heart of a magnetic one, and measured the electrical driving force (Electric Motive Force) in practice
In one of the two files as a result of the passage of the stream variable in the other file.

-zart For the first time in 1882 adapters composed of the file first single and multiple files, in order to obtain a secondary
Different values ​​for secondary efforts, has been the emergence of the nucleus of magnetic transformers closed in 1884, the beginning of any
Industrial use of transformers in converting electrical energy into high efforts, and transported over long distances, has
It was the first to this step brothers John and Edward Hopkinson, where they converted making simple composed
Nucleus of steel plates isolated, and two files, one for low voltage and other high voltage.


-obadha Came Hungarian world “and sees” who was the first to launch adapter name TRANSFORMER) on
These devices are created later on the idea of ​​connecting transformers in parallel.


Either for Tripartite adapters it has been the Russian world (the Dolev-Dobrovolsky) first invented transferred
Triple in 1889.

* Rating transformers (Classification of the Transformers):

Electrical -maholh are static electromagnetic device that converts electrical power to alternating current
From one form to another
-thoi Transferred Melvin at least intertwined magnetically and mechanically stable, call connected View
With network connected initial file and the file with the file we call the consumer Althano


-oimkn Division of transformers, according to the areas of their uses:

1-power converters (Power Transformers):
And that converts electrical power from efforts to another level, and are used in power transmission in various manufacturing fields and in the household uses


2-adapters regulation and calibration (Regulation Transformers):
And it is used for different values ​​of the effort in the laboratory
And research centers and automatic control ability 0 adapter


3 -mahullac to change the number of phases of the power supply (m):
AC frequency (f) and pulse shape and are primarily used in devices
Electronic, telecommunications and automatic control does not exceed the capacity, such as
These adapters are several Voltat amperes


4-measuring transformers (Measurement Transformers):
Such as serial power transformers and voltage transformers are used subsidiarity
In electrical measurements in distribution boards and nutrition

The transformers are divided in terms of the number of stages to:
1. The single-phase transformer Monophase Transformers
2. The three-phase transformers Three-phase Transformers
3. multiple adapters eccentric Polyphase Transformer

-otksm In terms of ratios converted to:

1-adapters decreases voltage:
You convert your initial file V1 high voltage to low voltage V2 (V1> V2) 0

2-adapters lever for the effort:
Convert your initial file V1 effort to high secondary voltage V2 (V1 <V2) 0

-omn Where the method of cooling is divided into:

1-dry transformers: cooled natural or forced air which is in the habit of transformer capacities
Small and medium


2-adapters Mgamsh oil: and are cooled by oil Kmahullac medium power rating of power
And large used in various electrical terminals, characterized by these adapters dangers of explosion and this provides an advanced control circuits


3-transformers are cooled gas sixth sulfur Fluor (SF6): The common use in recent indoor


* Transformer structure (Construction of the Transformers):


-taatolv Electrical transferred from the active materials (magnetic core and files) which is involved in operations
Electromagnetic in the converted, and construction materials (Kalawazl body and converted oil tank and stretched)


1-magnetic core:

Consisting of magnetic core assembled from thin rods and plates isolated from each other, put them files
Electrical and bridges also assembled from thin sheets up and isolated between the bars

-uejtlv Shaped magnetic core section of the transferred to another whenever the number of scales increased nucleus improved coefficient

Circle surrounding the nucleus magnetic article is full of effective and thus improve the coefficient of the use of the converted, but in return

It increases the complexity of the technological process to assemble the nucleus as it should be used for different sheets


-otstkhaddm In large transformer iron girders to install the magnetic core and compressed well, and sometimes damage

Transferred rods tapes, insulating solid so as to minimize as much as possible in the converted Alziaat


You must be characterized files transferred to the following:

1-mechanical durability high enough to protect them from the distortions that may result from the palace streams and currents in excess


2-durability sufficient heat so that the temperature rise does not lead to the collapse of thermally insulating materia

3-sufficient durability of electrical insulating material so that the insulation distances are sufficient to prevent the collapse of an electric or electric arc


Files transferred -takhtlv depending on currents and their nominal manufactured from either copper wires or with Almenyumah
Circular or rectangular section

* Converted principle of action (The Principle of Operation of the Transformer)
-fahm Different transferred business and develop a mathematical model to her, should initially study the principle of action transferred idealism and put her sports model


And we mean Bamaholh idealism of those transferred in which achieved the following:
1-neglect in which the electric field files
2-Alziaat is lacking, any internal resistance of iron and files equal to zero
3-magnetic permeability of iron is infinite, or magnetic resistance of the iron-existent
4-leakage magnetic careless


-nfrd We have reached initial file (which is the number of death N1)
With a source of alternating current with the voltage V1 and the frequency f1
And therefore it will pass aC amount i1, and this
The current turn will generate a flood magnetically alternating
Oslash, passing through the iron core lines in the converted
Idealism, and sections of it seeps through the air in the converted


-If Upstream Jibia effort shall flux generated & Oslash; Jibia also
Assume that the flux gives the following relationship:
& Oslash; = & Oslash; m * sin wt


Q -agaymh instantaneous magnetic flux wb
& Oslash; m -agaymh Great magnetic flux wb
W = 2 * pi * f -aserah corner of the stream sinus 1 / secF -altrdd HZ


-achapk This flux generated with all my laps initial and secondary forms Vbin intertwined with the initial files
And secondary Mekdaarhama:
& Oslash; 1 = N1 * ¥
& Oslash; 2 = N2 * ¥


-ihrd Alvbin 1 ¥, 2 ¥ in the primary and secondary files e1, e2 and indicative value Mahrkhkahrbaiah force generated in the primary winding and the secondary View


-nsma Ratio of the number of laps by primary and secondary conversion, symbolized by the symbol (K)
K = N1 / N2 = E1 / E2


-When Be conversion ratio (K> 1), the E1> E2, and thus transferred decreases effort, but if the conversion ratio (K <1), the E1 <E2, and thus transferred lever effort


-tattabr Circuit initial transferred as a consumer of electrical power, so the direction of beam electric driving force Altrdh

Of the magnetic flux & Oslash; be opposite to the direction of the actual vehicle for a stream of primary circuit beam, while the secondary circuit shall be considered

As the birthplace of the stream so the beam direction of electric driving force in the secondary coil Altrdh be in conformity with the composite beam

Actual stream secondary circuit Thus, if the direction of winding the two files and one (two files are identical) were two forces Mahrkian Alkahrbaiatin E1, E2 are consistent in direction and was mercaptans Alflitan primary and secondary currents opposite direction


* Converted work on vacuum:
-almqsod Converted job on the vacuum is work without a load, ie, when the primary winding is connected with the network,
Secondary and file open and is not connected with any load, in this case, the secondary file stream equal to zero
(I2 = 0) The effort on both ends of the secondary coil shall be equal to the effort transferred to the vacuum (V20), and consume like
This transferred from the network stream of (I10) call transferred to a vacuum stream


– And take advantage of the current work on the vacuum I10 in the generation of magnetic flux in the core, so this trend is sometimes called stream
Im magnetization (in the idyllic be transferred magnetization current equal to the current work on the vacuum (I10-Im).


-nsma Factor which gives the ratio of the converted stream on the vacuum to the nominal power of a converted (by a factor of evil (Kr
Kr = (I10 / Im) * 100%

-atalq This factor is transferred can range between (5.2 to 5.1)% in the large transformers, and 10% in transformers
Medium, and up to (60-40%) in small transformers


* Converted work on the palace:
-akabl It transferred work under load infinitely in old age, so that a secondary current is very large values, and this is done when
Palace of the secondary circuit zero resistance (Z = 0), any wire colorless resistance, the secondary voltage equal to zero (V2 = 0) and the currents passing through the primary and secondary files are equal to the currents of the palace


* Alziaat in the converted (Losses In Transformer):

-pma That the electrical device converter residents so it Ziaat mechanical Kalaankak No
-tsthlk Converted virtual capacity (S1 = V1 * I1), and consumes part of it to cover various Alziaat in Maholhoaisal to the consumer S2 = V2 * I2

-tksm Alziaat in the converted into electrical Ziaat acted in files and related Carrying the load so named Balziaat
Changing (Alziaat copper), and to Ziaat ferrous metal (magnetic) appear in the nucleus are not affected stream load, even by force
Electric motor, so we call fixed Balziaat.


1-electric Alziaat (Electric Losses):
It Alziaat concerning stream transferred I2, it includes these Alziaat (electric Alziaat in the files, and Alziaat
Additional induced cyclonic currents within the files because of erratic power supply distribution in, and additional Alziaat
Resulting from the cyclonic currents outside files, and transferred Basin (if any), and the complementary parts because Altserbalkahromagnatisa in the converted
(Pcu = n (r1 * I1² + r2 * I2² Pcu- electrical Alziaat estimates watts


-add Eccentric r1, r2- per phase resistance for each of the primary, secondary and estimated Ohms
I1, I2- current phase of the primary, secondary and estimated amperes

-oimkn Electrical Mufakid calculated using the secondary his mansion compartment adapter in this case must be the primary tension even slightly originates in the secondary stream full load measures the possible scale located in the primary circuit of electrical Alziaat at full load and as the primary tension small so be Mufakid rail small and can be neglected and electric ranges between Alziaat (3% -4%) of the transferred capacity


-alziaat Fixed rail (magnetic) Magnetic Losses:
These are called Alziaat fixed Balziaat not to hang Carrying the load, but the effort applied to the converted, including Alziaat
By cyclonic currents within the iron core, and the loss due to the magnetic Bata, and added to the rail Alziaat
Another type is the loss in the converted insulators, where the proportion of this loss with electric driving force transferred to the square.


-taatalq Mphaqad magnetic Bata both:
1-iron the size of the user
2-frequency power
Great 3-magnetic flow value

-otaatalq Mphaqad Foucault currents cyclonic both:
1-iron the size of the user
2-frequency power
Great 3-magnetic flow value
4-plate size of each of the transferred sheets


-oimkn Mufakid rail account for a converted try Allahml (open circuit test) is used in this case tension
The average converted and leave the secondary circuit open indicates possible located in the primary circuit on the value scale
Mufakid iron, copper and neglect Mufakid in the primary because Allahml be a small stream, and there is no copper Mphaqad
In the secondary because his mansion open, ranging between rail Mufakid (2% -3%) of the transferred capacity


* Converted payoff:
-ataleg This name on the ratio of the electric possible taken from the converted (output) and electric possible

Given to the converted (income), namely:
μ = P2 / P1
μ-yield 0
P1 -dechl transferred
P2 -khrj transferred


And given the real capacity transferred the following relationship:
P = U * I * cos & Oslash; Of a converted single-phase
P = sqort 3 * I * U * cos & Oslash; Three-way stage of the converted


* The daily yield:
It is calculated by dividing the electric power derived from the converter per day on electric power given to the adapter’s Day


* Ability and tension:
-and Arrived secondary circuit converted with carrying the phase difference angle will vary depending on the type of load, whether physically or inflammatory

Or Sauaa as well as vary the actual possible stated and actual factor possible by changes in the type of pregnancy
Therefore be possible virtual S (is the sum total of the actual engineering capacity P stated the actual Q) is measured

Pal (VA, KVA, MVA) transformers are classified in terms of its ability to face two series, namely:
1-adapters key chain (HET): It allows to download the converter here a few worth in excess of par recorded on being able to face painting


2-adapters special series (SET): It allows downloading here converted to carry plus the par possible for a few weeks a year


-lmahullac Par with the greatest possible from 16 kva given tension Allahml secondary file and the reason for that is to know

Properties of pregnancy transferred, if the load transferred Omi tension V2 decreases slightly when the pregnancy for when Allahml, as for pregnancy inciting the tension V2 fall further, while in the capacitive load increases the tension V2 Bazdaadalhml


* Ways to organize the converted voltage:
-eetm Organization transferred an effort to change the conversion ratio (K = N1 / N2) by changing the number of laps primary winding N1 and secondary N2, and is organized in this way in the form of leaps, that’s why one of the two files equips several ramifications end to several external stalls easily changed and altered, moving from stall to another by special devices Balambdlat call (Commutator) are either single-phase or three-phase type, according to the converted


-ovi Adapters that the initial effort where constant (V1 = const) are voltage regulation on the one hand the secondary coil to change the number of death N2 Thus magnetic flux and Alziaat magnetic stream magnetization that suit all of us with the ratio V1 / N1 almost constant remains if we kept on the number of initial laps and his steadfast

Either the adapters that operate at constant load (I2 = const) and the initial effort variable, prefers to be organized effort to change the number of laps the initial file


Either voltage regulation are transferred either after the separation of the consumer and the way we call the organization at a vacuum, or without a chapter on nutrition and consumer call it a way that regulation under load


1. Voltage regulation after transferred from the network separation (regulation on space):

-used A way to regulate the voltage transformers that feed consumers of the second category, third and fourth, where there is a cut of nutrition for the consumer any dangerous or harm to humans or the machine or production, where this method is used to regulate and compensate the voltage drop in the secondary distribution transformers, or change according to the level of the initial effort in the neighborhood, or one section of the public network, and is also used for the seasonal changes of the work of the network (in summer, winter, for example)


Cons of this method is the need to cut nutrition for the consumer during the period of regulation and this is what limits the repetition of voltage regulation through the work of the converted


Preparing regular transformers used in power transmission and distribution additional Bmrabot believes in raising or lowering the voltage by (1% – + 3%; – + 5% + _) Nominal voltage from her


-eetm Regulation of the body that are exposed to changes in the effort during the converted investment, and so the iceberg remains the nucleus almost constant at the transition from the shunt to the other, and more often than preferred organization on the one hand the high voltage because the number of windings be great compared with the low-voltage profile, and the mainstream at the high end is smaller than it allows the use of switches and breakers cheap price designed to work at low currents

2-regulation under load:
-used This way of transformers that feed the first category, such as hospitals and high furnaces, etc., where
It is a cut-off for the consumer even for a brief period of a danger to public health and the production


-eetm Switch during the load without cutting the power cord of consumer good and smoothly (+ – 1%) pass transferred through the switch in a transient state (Transient Procces) where the Tafriatan adjacent rings connected with some Tqsran portion of trapped between the file and passes two transient currents, and to limit this palace currents used Gorges enticing or effective for the exclusive stream


Placed suffocating file and switched in a bowl of oil kept in the converted, while cutouts mechanism placed in another pot filled with oil cooler and attached to the side of the vasa mother


* Connect transformers in parallel (Parallel Connection):
-used In electrical substations lever or lowering voltage range of transformers connected with each other on

branching, and the purpose of this link is:
1-secured consumer to provide electrical power in the event of a malfunction in some transformers and the need for reform

2-Ziaat reduce energy loads during the minimum separating section transformers connected in parallel and reconnecting the second transformer with the network when increasing the load

Either the number of adapters that can be connected with each other on the branching are chosen from the plant capacity

After an economic and technical study of the plant or industrial facility

* Terms connecting transformers to forking:
Even optimal work for transformers tethered to forking achieved should be distributed to the general cargo terminal between operating transformers and connected to the branching by the distribution of nominal virtual Asttaatha ratios, and to achieve load distribution between the transformer connected to the branching in this way should

provide the optimal conditions are three:

1. be one conductivity groups (succession of phases one) at all connected to the transformer

2-par efforts to be of primary and secondary files are equal among themselves and thus to be a conversion ratios


3-palace that the actual efforts and their compounds and evil be equal among all transformers

-and Arrived transformers on forking advised that relatively short effort is no different from the average value of the effort relatively short all of the transformers by more than (+ – 10%) to that if uneven got more than this value, the bulk of the load borne by the converted with smaller palace effort and thus these transferred will face its capacity at a time when the rest of the transformer is loaded with cargo be nominal full and that means we can not take advantage of the full capacity connected to the branching transformers


– And must not exceed the rates of nominal power rating of transformers connected to the branching ratio (3: 1


* Converted self (Autotransformer):
– Converted be called that Melvaha intertwined magnetically and electrically connected Bamaholh self 0
-tantql Electric power from the primary winding to the secondary coil by magnetic agitation and contact electrode both self and transferred is a single file to be the secondary rolls part of the primary
Or vice versa, if reached initial circuit to an electric source of tension V, the tension on both ends of the primary circuit is) V1 = V), and be tension on both ends of the secondary circuit:
V2 = V1 * (N1 / N2)

If the severity of the current flowing in the primary, the load current I1 I2 is equal to:
I2 = I1 * (N2 / N1)

As for passing the joint portion of the stream of Aldartin is I2 ‘and is equal to:

I2 ‘= I2 – I1

Since the current flowing in the secondary coil is equal to the difference between Hdta currents I1, I2 then be Oslake clip

Small in comparison with the normal transformer and here the idea of ​​the economy appear in copper weight in this part of the circuit

And thus in the self-converter whenever the conversion ratio of small n whenever the economy was in the weight of

copper and the largest user can be demonstrated through the following relationship:

Copper weight in the self-converter = (n-1)

Copper weight in the normal n Adapter

It is this relationship, we find that the amount of copper in the economy not be of value when considering small conversion rates

-astamal Self-converter:

Using self-converter start engines inflammatory movement in order to reduce the tension at the start of the movement,
It is also used to feed safety lamps 24 v electric bells and in homes, as Kmazer used to raise the voltage at the end of lines used in electrical distribution networks (lift) adapter


* Multiphase converters:

The more multi-phase currents is the most commonly used three-phase power, where the reach of secondary and primary files

Either (a stellar -ndjema or trigonometric or trigonometric -mthelta – stellar or astral -mtarj or trigonometric -mtarj)

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