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Your location: Home > Related Articles > Can ordinary circuit breakers be used for direct current

Can ordinary circuit breakers be used for direct current

Author:QINSUN Released in:2023-06 Click:156

Generally, it is generally used for AC circuit on-off. If it can be used for direct current, the key is whether the direct current can be cut off.

For alternating current, when the contacts are broken, an arc will be generated, this is called the \"arc phenomenon\". However, the characteristic of alternating current is that it has a \"zero crossing\" state. When the current passes through zero, it cooperates with the cooling effect of the arc quencher to quickly quench the arc, thereby breaking the circuit.

Here, the contacts that cut the current are important, but what really matters is how to cut the arc. Due to the high temperature and ablation caused by the arc, this is the key to determining contact life.

The so-called DC current is not easy to cut, which means the DC arc is not easy to cut. The reason for this is that the DC arc does not have a \"crossing to z\" state.ero\", so it is not easy to break the arc despite the cooling of the arcfall. The existence time of the arc is the key to determine the life of the contact.

As to why the DC current of the circuit breaker is only one tenth of the AC current, it should be the manufacturer\'s test data, because it is easy to understand that the DC current passed through the circuit breaker is lower. When breaking, although the arcing time is long, it is easier to extinguish the arc.Naturally, the service life of the contact system is guaranteed to be the same as when passing through the exchange.We We can also refer to this principle when we choose circuit breakers and switches.If you ask the manufacturer if it can be used for direct current, he will say the same thing.

By the way, if the circuit breaker can be used for direct current, it is not only if the contact can cut off direct current, but also to ensure the service life of the contact system. If the contact system can only be disconnected a few times before hanging up, such a circuit breaker cannot be used.

There are also DC circuit breakers, including the internal contacts and the extinguishing system of arc are basically the same as those of alternating current. It\'s just that the manufacturer calibrated it according to the size of the direct current. So what you see is that the \"rated continuous current\" passed through the circuit breaker which seems to be quite large is not large, and that is the reason.

To put it bluntly, it is recommended to choose a DC circuit breaker for the circuit breaker. After all, the circuit breaker must have a setting value in addition to whether it can interrupt direct current. If you choose a DC circuit breaker, it is regulated according to the DC current. If you directly use the AC circuit breaker instead, there is nohas no setting value. It can only guarantee that the direct current can be cut off manually. Of course, if you choose contactors and relays, that\'s another matter.