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Basic knowledge of transformer

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Time of issue:2020-12-10
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(Summary description)Basic knowledge of transformer Transformers are used in almost all electronic products. Its principle is simple but According to different use occasions

Basic knowledge of transformer

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Basic knowledge of transformer

(Summary description)Basic knowledge of transformer Transformers are used in almost all electronic products. Its principle is simple but According to different use occasions

Categories:News
Author:
Origin:
Time of issue:2020-12-10
Views:0

Information

Transformers are used in almost all electronic products. Its principle is simple but

According to different use occasions

(Different uses)

The winding process of the transformer will be different

Claim. The main functions of the transformer are: voltage transformation; impedance transformation; isolation; voltage stabilization (magnetic

Saturation transformer), etc. The core shapes commonly used in transformers generally have

Type and

Type iron core.

One, the basic principle of the transformer

Is a simplified diagram of the principle of a transformer,

When a sinusoidal AC voltage

When added to both ends of the primary coil,

In the wire

Alternating current

And produce alternating magnetic flux

, It passes through the primary coil and the secondary coil along the core to form a closed magnetic circuit. In time

Mutual induction potential is induced in the first coil

,Simultaneously

Will also induce a self-induced potential on the primary coil

The direction of

Applied voltage

The direction is opposite but the amplitude is similar,

Thereby limiting

the size of.

In order to maintain the magnetic flux

Need to have a

Certain power consumption,

And the transformer itself also has a certain loss,

Although the secondary is not connected to the load at this time,

There is still a certain amount in the primary coil

This current is called "no-load current".

If the secondary is connected to a load, the secondary coil will generate current

, And therefore generate magnetic flux

The direction of

in contrast,

Play a role in canceling each other, so that the total magnetic flux in the core is reduced, so that the primary self-inductance voltage

Reduced, as a result

Increase, it can be seen that the primary current is closely related to the secondary load. When the secondary load current increases

increase,

Also increase,

and

The added part just complements the

The part of the magnetic flux that is canceled,

To keep the total magnetic flux in the core unchanged.

if not

Consider the loss of the transformer,

It can be considered that the power consumed by the secondary load of an ideal transformer is the power that the primary draws from the power supply.

power.

The transformer can change the secondary voltage by changing the number of turns of the secondary coil as needed.

But the allowable load consumption cannot be changed

Power.

Second, the loss of the transformer

When the primary winding of the transformer is energized, the magnetic flux generated by the coil flows in the iron core, because the iron core itself is also a conductor.

In a plane perpendicular to the lines of magnetic force, an electric potential is induced,

This potential forms a closed loop on the cross section of the core and generates current,

it is good

It is like a vortex so it is called "vortex".

This "eddy current" increases the loss of the transformer,

And make the core of the transformer heat up

The temperature rise of the compressor increases.

The loss caused by "eddy current" is called "iron loss".

In addition to winding the transformer, a large amount of

Copper wire,

These copper wires have resistance,

This resistor will consume a certain amount of power when current flows.

This part of the loss often turns into heat

As for consumption, we call this loss "copper loss". Therefore, the temperature rise of the transformer is mainly caused by iron loss and copper loss.

Since the transformer has iron loss and copper loss, its output power will always be less than the input power. For this reason, we have introduced

An efficiency parameter to describe this,

Output Power

input power.

Three, the material of the transformer

To wind a transformer, we must have a certain understanding of the materials related to the transformer. For this reason, I will introduce

Some knowledge in this area.

, Core material:

The core materials used in transformers are mainly iron sheets, low silicon sheets, and high silicon sheets. The addition of silicon to the steel sheets can reduce the conduction of the steel sheets.

Electricity, increase the resistivity, it can reduce the eddy current and reduce its loss. We usually call silicon-added steel sheets as silicon steel sheets.

The quality of the silicon steel sheet used in the quality of the device has a great relationship,

The quality of silicon steel sheet usually uses magnetic flux density

To represent,

General black iron

Piece

Value is

6000-8000

, Low silicon wafer is

9000-11000

, High silicon wafer is

12000-16000

, The materials commonly used for winding transformers are

Enameled wire, sand-bag wire, silk-covered wire, the most commonly used enameled wire. The requirements for wires are good electrical conductivity and insulating paint

The layer has sufficient heat resistance and a certain degree of corrosion resistance. Best to use under normal circumstances

Model of high-strength polyester paint

Envelope.

,Insulation Materials

In the winding transformer, the isolation between the coil frame layers and the isolation between the winding resistances all use insulating materials.

The frame material of the press can be made of phenolic cardboard,

The layers can be separated by polyester film or telephone paper,

The winding room can be isolated by yellow wax cloth.

, Impregnation material:

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