How to prove circuit overcurrent? Introduction to overcurrent

Dude, you can say in your question:

1: In your question, the burning of components or lines has proved that the current must be greater than the overload. This can be proved by the fact that there was once a large current load, and there was once a component that burned out.

If the circuits and components are still in good working order and do not show obvious signs of aging, it does not mean that the current has been excessive.

2: If you want to distinguish whether the quality of the components itself is not up to par and burn, or the current or voltage from the upper line is too large to cause burning. Such elements exist.

Like the air turn switch, a simple fuse can do this (the fuse is the main cause of excessive current, but in the case of a certain total power of the electrical appliance, if the voltage is too large, it will cause the current to be excessive and blow the fuse).

The control circuit measures the load current, which can be achieved by means of a transformer or Hall element. The simplest, fuses, air trip switches, fuses. That's it.

The current burns the line because the current produces heat. So we use thermal relays or fuses to protect the line or equipment. Of course, methods such as overcurrent protection in circuit breakers can also be used.

The first problem: when a large current is suddenly added to the same circuit, other loads or components on the line will trip or heat and burn due to the sudden change of line voltage and current, so we add air switches, fuses, thermal relays and other components on the road to control and protect the equipment (the specific size needs to be calculated).As for the proof, it is necessary to analyze it according to the actual situation on the spot.

Add a signal relay and set the fixed value.

Wouldn't it be nice to add a fuse yourself, or just open it empty?

Precise over-current protection and detection are achieved by dividing the voltage with a small value resistor, and using differential amplification, peak detection, and over-current judgment.

First of all, a small value resistor is connected in series at the output end (for example, when the current is 10A, the voltage drop is only, so the linear output characteristics of the voltage can be basically guaranteed.

Then the voltage differential at both ends of the small value resistor is amplified (referring to the differential amplifier), at this time, the AD sampling digital can be used to calculate, judge the output current, set the threshold, when the current is greater than the threshold, the digital circuit outputs the action signal S1, and the red light is on at this time, otherwise the output S0 is on, and the green light is on.

Or after differential amplification, pass through the comparator, manually adjust the comparison threshold, when the current is greater than the threshold value, the output high level drive red light is on, otherwise the output low level drive green light is on.

Overcurrent: The electro-hydraulic that exceeds the rated current is called the front flow. The loop current that is greater than the rated load current of the circuit conductor is overcurrent.

It includes overload currents and seepage short-circuit currents. The distinction is that the overcurrent before the circuit insulation is damaged is called the overload current; The overcurrent after the insulation is damaged is called the short-circuit electric disturbance.