The first delivery after CNY holiday:
1.CAH (22) -400DV Cut to length Line *1 units
2. Slitting line

1. What does △/Y0-11 mean on the transformer nameplate?
Answer: According to the different connection methods of the primary coil and the secondary coil of the transformer, the phase angle of the line voltage on the primary side and the secondary side of the transformer is different. Transformer △/ Y0-11 means that the phase angle difference between the two line voltages of the transformer is 330°. It is customary to use the clock notation, that is, 11 o'clock.

No-load test: Apply the rated voltage of the sine wave rated frequency from a certain winding of the transformer (generally from the secondary low-voltage side), and open the other windings to measure the no-load current and no-load loss. If the test conditions are limited and the power supply voltage cannot reach the rated voltage, the test can be performed under non-rated voltage conditions. This test method has a large error and is generally only used to check whether the transformer is faulty. Only the test voltage reaches more than 80% of the rated voltage. can be used to test the no-load loss.

Oil-immersed transformers have the characteristics of good heat dissipation, low loss, large capacity and low price. At present, most of the power transformers running on the grid are oil-immersed transformers, of which more than 80% are cooled by natural oil circulation. It is a commonly used cooling structure to set a guide plate in the coil of a natural oil circulation transformer. This paper focuses on analyzing the structure, operation and maintenance of oil-immersed power transformers, and specifically analyzes the oil system of oil-immersed power transformers, and briefly analyzes the faults of oil-immersed power transformers. Hope to increase understanding and analysis of my country's oil-immersed power transformers.

Introduction
transformer
A device that changes voltage, current, or phase by coupling a magnetic circuit
Why learn Transformers?
Transformers are also known as stationary AC motors

This video showed you what a main power transformer look like.

Analysis of abnormal operation of transformers
Transformer sound is abnormal


As soon as the transformer is connected to the power supply, there will be a buzzing sound, which is mainly due to the effect of high-voltage magnetic flux. During normal operation, the sound of the transformer is uniform. When there are other noises, you should carefully find the cause and deal with it.

1. Analysis of abnormal operation of transformers
(1) The sound of the transformer is abnormal
As soon as the transformer is connected to the power supply, there will be a buzzing sound, which is mainly due to the effect of high-voltage magnetic flux. During normal operation, the sound of the transformer is uniform. When there are other noises, you should carefully find the cause and deal with it.

In AC circuit, there are three concepts of electric power: active power, reactive power and apparent power. KVA stands for apparent power, which includes reactive power and active power. KW stands for active power, and kVar stands for reactive power. The relation between kW and kVar and conversion there is a concept - power factor cos ф, active power kW=UIcos ф, reactive power kVar=UIsin ф, and apparent power kVA=UI(U is voltage, I is current).

The main materials of the transformer body include magnetic circuit materials, circuit materials, insulating materials, structural materials, etc.

Transformer body structure
This paper mainly introduces the structure of transformer body from three aspects: core, winding and lead.
I.Transformer core structure
01 The role of silicon steel(Iron) core
Transformers are based on the principle of electromagnetic induction, the magnetic circuit is the medium of electrical energy conversion. Iron core is the main magnetic circuit of the transformer, the main role is magnetic. It converts the electrical energy of the primary circuit into magnetic energy, and from magnetic energy into electrical energy of the secondary circuit.
At the same time, the iron core is the mechanical skeleton of the transformer, and the clamping device of the iron core not only makes the magnetic conductor into a mechanical complete structure, but also has an insulated coil on it, supporting the lead, and almost all the components inside the transformer. The weight of the iron core is the largest in the transformer components, accounting for about 60% of the total weight in the dry transformer, and about 40% in the oil-immersed transformer.