What are the reasons for the switchgear being burned?
In electrical work, have you encountered the problem of burning the switchgear?
Jiangxi Yikai Electric Co., Ltd. ,As a electrical switchgear manufacturer tell you about the reason why the power switchgear was burnt.
The main reasons for the burning of the power switchgear/switchboard are as follows:
1. The motor load cable or the switch bridge line (the parallel connection of the switch and the switch) is too thin.
When making the switchgear/ electrical panels, the wire does not match the actual load rated current.
For example, the rated current of a 22KW motor is about 44A, and your wire selection is 4mm2 copper core cable.
According to experience, the full load current of 4mm2 copper wire is about 30A, which is much lower than the rated current of the motor.
However, the probability of this situation is relatively low, and it is almost impossible for the original original switchgear to appear.
2. Auto-transformer or frequency-sensitive resistance cabinet can not be separated from the circuit for a long time
These two step-down starter cabinets must cut off the autotransformer or frequency-sensitive resistor from the circuit after completing the motor starting task. Otherwise, the coil will be overheated and burned due to long-term live operation.
3. Overload operation, overload protection device fails to operate
The setting current value of the thermal relay or the air switch thermal element with overload protection is adjusted too large, which makes the switchgear/panels work under overload for a long time, resulting in excessive temperature and even fire.
4. Contactor singeing, bad contact
This point is consistent with the description of the sub-topic.
When the contactor contacts are singed, uneven contact points will appear on the surface, which makes the contact area of the contact not enough to reach the rated current capacity of the contactor.
There will be a “fire” phenomenon, and over time, the contactor will be burned and cannot be used.
In addition, if the stroke of each contact of the contactor is inconsistent, a serious “fire” phenomenon may also occur.
5. Each terminal is loosely oxidized, resulting in poor contact
The possibility of this situation is very high, the main reason is that the terminal screws are loose or the lugs are not compressed.
Therefore, it is necessary to regularly check whether the screws are loose and whether the terminals are overheated.
The above reasons are the main factors that cause the components of the power switchgear/ panels boards to be burnt.