The coil of transformer is an important part of transformer. It is said that the heart of coil type transformer is very important to transformer. In the transformer, the coil is the part of the circuit. In the operation of the transformer, there will be some bad conditions such as over-voltage, high temperature and over-current. In order to make the transformer operate safely and reliably for a long time, the winding coil must meet the basic requirements of electricity, force and heat.

1.Requirements for electrical strength. In the long-term operation of transformer, the insulation of coil must withstand lightning impulse voltage, switching impulse voltage and long-term working voltage. Among them, we need professional testing equipment such as impluse voltage test system, comprehensive test system, Wire tester etc. In order to ensure that the transformer coil has sufficient electrical strength, in addition to adopting appropriate coil insulation structure and designing fully and reliably, the technological process of coil, the quality of material used and the production environment also have a decisive impact on the electrical strength of coil insulation.

2.Mechanical strength requirements. In the process of coil manufacturing, we must pay attention to the following points: 1) The line spoke must be short-sighted, the winding arrangement is neat, and there is no skew. 2) The coil cushion block is neat and vertical, the high and low voltage stay bars are aligned, and the transposition and explosion are reliable. 3) The coil is dried under constant pressure, and the axial pressing force is enough during assembly. 4) The height difference between coils is strictly controlled to reduce the axial force of coil. Therefore, our company Automatic winding machine, Paper wire wrapping machine, coil pressing machine etc could guarantee the production quality of coil.

3.Requirements for heat resistance strength. When the transformer is in operation, the loss of iron core, coil and structural parts will be transformed into heat and radiate to the outside, which will cause the transformer to heat and temperature rise. In order to ensure the service life of the coil, there should be sufficient external cooling conditions in the design of the transformer, as well as good cooling conditions inside the coil. That is to say, the longitudinal oil passage and the transverse oil passage meet the heat cooling requirements.Our company Automatic oil duct processing machine and wedge-shaped layer insulation HV winding machine is a new technology in this field to ensure the consistency and quality of the coil workpiece.