For power beginners who have just come into contact with transformer knowledge, there are always some confusing knowledge points in a large number of basic concepts. Transformer no-load operation One of which is a transformer load operation. Although there is a large amount of data to explain the two concepts separately, there is little data to explain the difference between the two.
Transformer running without load
The no-load operation of the transformer refers to the working state that the primary winding of the transformer is connected to the power supply and the secondary winding is open. At this time, the current in the primary winding is called the no-load current of the transformer. No-load current generates no-load magnetic field. Under the main magnetic field (that is, the magnetic field of the first and second windings at the same time), the electromotive force is induced in the first and second windings.
When the transformer is in no-load operation, although the secondary side has no power output, the primary side still absorbs a part of the active power from the grid to compensate for the hysteresis loss and eddy current loss caused by magnetic flux saturation in the core. The size of hysteresis loss depends on the frequency of the power supply and the area of the hysteresis loop of the core material. Eddy current loss is proportional to the square of the large flux density and frequency. In addition, there is copper consumption caused by no-load current. For different capacity transformers, the size of no-load current and no-load loss is different.
Transformer load operation
The load operation of transformer refers to the working condition when the primary winding is connected to the power supply voltage and the secondary winding is connected to the load. At this time, the secondary side of the transformer also has current flow, and the original variable access circuit is correspondingly large compared with the no-load, and the secondary side voltage will be affected by the load and change.
Normal periodic load operation:
1. The transformer can run at rated current throughout the year under rated use conditions.
2, the transformer allows the average relative aging rate is less than or equal to 1, the case of periodic over-fixed current operation.
3, when the transformer has a serious gap (such as abnormal cooling system, serious oil leakage, local overheating phenomenon, abnormal analysis results of dissolved gas in the oil, etc.) or insulation weakness, it is not appropriate to exceed the fixed current operation.
4, under the normal periodic load operation mode, when the excess constant current operation, the allowable load coefficient K2 and time can be determined according to one of the load guidelines.
The difference between the two
The main difference between transformer no-load operation and load operation is mainly reflected in the secondary coil, the transformer load operation secondary coil is connected to the load, generating large power, and the no-load operation secondary coil is open, generating micro power.
Transformers use the principle of electromagnetic induction to change the AC voltage device, the main components are primary coil, secondary coil and core (core). It is often used in electrical equipment and wireless circuits as lifting voltage, matching impedance, full isolation, etc. When the transformer is in no-load operation, it only consumes no-load loss, that is, iron loss and stray, which is the total capacity of 6 load operation is no-load loss + load loss, that is, copper loss is the total consumption of the transformer.
This paper introduces the no-load operation and load operation of the transformer respectively, and explains the difference between the two in detail after completing the foundation of the basic knowledge, which is a very suitable article for beginners to read. I hope that friends who have questions about no-load and load can solve the confusion after reading this article.
