What is the significance of the rating on the transformer nameplate? Why is the unit of rated capacity SN of transformer kilovolt-ampere (or volt-ampere) instead of kilowatt (or watt)?

Significance of transformer rating: the rating is stipulated by the manufacturer for the normal use of transformer. Only when the transformer runs under the specified rating can it ensure long-term reliable work and good performance.

The unit of rated capacity SN of transformer is kilovolt-ampere (or volt-ampere), not kilowatt (or watt):

1. The rated capacity of the transformer is the apparent power (unit: KVA), not the active power (unit: kw).

2. Apparent power is a kind of comprehensive power, including active power and reactive power.

3. Active power is the power consumed on the resistance load, and it is the power that actually does work, which converts electric energy into heat energy, chemical energy, mechanical energy, etc. The unit of active power is defined as kilowatt.

4. Reactive power is the power consumed by inductive or capacitive loads, which actually does no work and returns energy to the power grid. The exact unit is kilojoule.

Transformer is a device that uses electromagnetic induction principle to change AC voltage. The main components are primary coil, secondary coil and iron core (magnetic core). The main functions are: voltage transformation, current transformation, impedance transformation, isolation, voltage stabilization (magnetic saturation transformer) and so on. According to the purpose, it can be divided into: power transformer and special transformer (electric furnace transformer, rectifier transformer, power frequency test transformer, voltage regulator, mine transformer, audio transformer, intermediate frequency transformer, high frequency transformer, impulse transformer, instrument transformer, electronic transformer, reactor, transformer, etc. ).