Do you know about the No-load Operation of Transformer?

No-load Operation of Transformer
No-load operation of transformer means that the primary winding of transformer is connected to power supply and the secondary winding is open. At this time, the current in primary winding is called no-load current of transformer. No-load current produces no-load magnetic field. Under the action of the main magnetic field (that is, the magnetic field of the first and second windings crosslinked at the same time), the electromotive force is induced in the first and second windings.

Transformer Load Operation

1. Transformers can operate at rated current throughout the year under rated operating conditions.
2. Transformers are allowed to operate periodically over rated current when the average relative aging rate is less than or equal to 1.
3. When the transformer has serious defects (such as abnormal cooling system, serious oil leakage, local overheating, abnormal results of dissolved gas analysis in oil, etc.) or insulation weaknesses, it is not suitable to operate at excess rated current.
4. Under normal periodic load operation mode, the allowable load coefficient K2 and time can be determined according to one of the methods of load guide when the overrated current is running.

The difference between them
The main difference between no-load operation and load operation of transformer is mainly reflected in the secondary coils. The secondary coils of transformer load operation connect with the load, resulting in high power, open secondary coils of no-load operation, and micro power.

The transformer uses the principle of electromagnetic induction to change the AC voltage. Its main components are primary coil, secondary coil and core. In electrical equipment and radio circuit, it is often used for up-and-down voltage, matching impedance, safety isolation, etc. When transformer runs without load, it only consumes no-load loss, i.e. iron loss and stray, which is 6% of the total capacity. When transformer runs under load, it consumes no-load loss + load loss, i.e. copper loss, which is the total consumption of transformer.

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