Transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil and the iron core (magnetic core). It is a kind of voltage conversion, current conversion, impedance conversion, isolation, and voltage stabilization. (Magnetic saturation transformer) and other functions of electrical equipment.

Common transformer

• distribution transformers are used in the distribution system to convert the power of the medium-voltage distribution voltage into low-voltage distribution voltage power for various low-voltage electrical equipment. Distribution transformer capacity is small, generally 2500kVA and below, a voltage is also low, are in 20kV and below.

• All transformers used in the power grid are collectively referred to as power transformers, that is, transformers at all levels before distribution, and the primary voltage is generally 35kV and above.

• Box-type substation (European) structure is mainly divided into three parts: high-voltage switchgear, transformer and low-voltage distribution device. High-voltage switchgear is generally composed of high-voltage load switches, high-voltage fuses and lightning arresters, and low-voltage chambers are composed of low-voltage air switches, current transformers, ammeters, and voltmeters.

• The box-type substation (American) structure is divided into front and rear parts. The front part is a wiring cabinet, which includes high and low voltage terminals, high voltage load switches, fuses, high voltage tap-switches, etc. The rear part is an oil tank and a heat sink. Transformer windings, iron cores, high voltage load switches and fuses are all in the oil tank body, and the tank adopts a fully sealed structure.

Transformer international certification-UL certification

UL certification in the transformer industry is the best choice to enter the North American market, but it is also the most complex. Unlike IEC, transformers going to North America have different certification standards according to different insulation types, voltage levels, etc.

Transformer application UL certification required information

1. the application form;

2. Business license;

3. English version of the product manual (to indicate the maximum ambient temperature of the product);

4. English version of product specifications (including internal structure drawings and product drawings);

5. List of key components;

6. Nameplate (including product name, model, parameter, Logo and trademark);

7. Other technical data (evaluation after product provision)

transformer UL certification process

1. Data and sample review;

2. Officially open the case;

(3) testing;

preparation of the report;

5. Submit the certificate;

6. First factory inspection IPI (if necessary)