Electronic overload means that the operating current of the electrical equipment exceeds its rated or allowed current.
Overload will easily lead to the temperature rise of the line and the electrical equipment, damage the insulation of the electrical equipment and the line, there are safety risks in the operation of the equipment, so some important equipment and the line need to take certain measures to protect, which is called electronic overload protection.
Overload is the load is too large, more than the rated load of the equipment itself, the phenomenon is the current is too large, electric equipment heating, long-term overload line will reduce the line insulation level, or even burn down the equipment or line.
An overload protection device installed to prevent the main power line from overheating and damaging the protector due to overload.
Overload is a broad term that can mean either too much load on an electrical device or too much force on an object.
Protection against these "overload" actions is called overload protection.
In the communication power supply system, the function that the power supply is automatically disconnected due to the excessive load is called overload protection.
The figure is the primary circuit of the general motor. In the figure, from top to bottom are circuit breaker QF, ac contactor KM, thermal relay FR and motor M.
The FR in the figure plays the role of motor overload protection, while QF is the line overload protection. However, these protection can only play an effective role with reasonable fixed value Settings.
In the process of motor M operation, if overload operation, then reach the set value and time, the thermal relay FR will play a role, cut off the power supply, to protect the motor.
But his accuracy is not high, the protection function is weak.
The above figure relies on thermal relays for overheating protection, which were popular a few years ago, but now most motor circuits rely on motor protectors.
This method differs from the traditional method mentioned above in that the latter replaces the traditional thermal relay with a motor protector and relies on the current transformer in the circuit to collect the operating current and compare it with the set value.
This kind of motor protector has many advantages, such as powerful function, complete types of protection, high accuracy of setting value, no misoperation, and convenient operation, and gradually replaces the traditional thermal relay protection.
