What Is Overload? What Is Overcurrent? Did You Know~ （1）

Every electrical device used in the power grid or in our daily life will have a rated power. When the power of the device is higher than the rated power, we call it to overload.

Likewise, we will call this protection overrated power overload protection.

Another point to mention here is that when the equipment is overloaded, it is easy to cause a short circuit in the electrical equipment.

We call those protections that specifically protect against short-circuit faults inside the device to short-circuit protection.

What is overcurrent?

Both overcurrent and overload are a state. Among them, overcurrent is an operating state of electrical equipment when the motor or other electrical components are higher than the rated current.。

Normally, the overcurrent is not higher than the short-circuit current and is within six times the rated current.

What is overload?

The overload operating state falls within the category of the overcurrent operating state because it is a state in which the motor operating current exceeds the rated current and is within 1.5 times.

If the electrical equipment is in overload operation for a long time, the temperature rise of its winding will exceed the allowable value, resulting in aging or damage to the winding insulation.

Overload protection：

Overload protection is often achieved by thermal relays, which can act instantaneously without being affected by short-term overload impulse current or short-circuit current of the motor.

However, fuses or low-voltage circuit breakers should also be used synchronously, because when a current exceeding 6 times the rated current passes through the thermal relay, it will act slowly, at least after five seconds.

This will cause the heating element of the thermal relay to be burnt out when it operates.