Transformer classification

Classification of furnace transformer

Classification by cooling mode: dry type (self cooling) transformer, oil immersed (self cooling) transformer and fluoride (evaporative cooling) transformer.

Classified by moisture-proof mode: open transformer, potted transformer and sealed transformer.

Classification by iron core or coil structure: core transformer (insert iron core, C-type iron core and ferrite iron core), shell transformer (insert iron core, C-type iron core and ferrite iron core), ring transformer and metal foil transformer.

According to the number of power phases: single-phase transformer, three-phase transformer and multi-phase transformer.

Classification by purpose: power transformer, voltage regulating transformer, audio transformer, medium frequency transformer, high frequency transformer and pulse transformer.

Working frequency

The loss of transformer core is closely related to the frequency, so it should be designed and used according to the use frequency, which is called the working frequency.

Rated power

Under the specified frequency and voltage, the transformer can work for a long time without exceeding the output power of the specified temperature rise.

Rated voltage

It refers to the voltage allowed to be applied on the coil of the transformer, which shall not be greater than the specified value during operation.

Voltage ratio

It refers to the ratio of primary voltage and secondary voltage of transformer, which is different from no-load voltage ratio and load voltage ratio.

No load current

When the secondary of the transformer is open circuit, there is still a certain current in the primary, which is called no-load current. The no-load current is composed of magnetization current (generated magnetic flux) and iron loss current (caused by core loss). For 50Hz power transformer, the no-load current is basically equal to the magnetization current.

No load loss

Refers to the power loss measured in the primary when the secondary of the transformer is open circuit. The main loss is the core loss, followed by the loss of no-load current on the copper resistance of the primary coil (copper loss), which is very small.

Efficiency

Refers to the percentage of the ratio of secondary power P2 to primary power P1. Generally, under the same volume, the greater the rated power of the transformer, the higher the efficiency.

Insulation resistance

It indicates the insulation performance between coils of transformer and between coils and iron core. The insulation resistance is related to the performance, temperature and humidity of the insulating material used.

Effect of EAF transformer

Transformer is a static electrical equipment. It is a device that converts a certain level of AC voltage and current into another level of voltage and current with the same frequency according to the principle of electromagnetic induction. Functions: Transform AC voltage, exchange AC current, transform impedance and power transmission.