Air switch, also known as automatic switch, low-voltage circuit breaker, etc. , is a common circuit protector in family and engineering. When the working current exceeds the rated current, short circuit, voltage loss, etc. It automatically cuts off the circuit to realize protection.
In addition to the protection function, it can also be used with leakage device, measurement, electric operation and other module units. In low-voltage distribution system, it is often used as a terminal switch or a branch switch to replace the fuse and knife switch commonly used in the past.
What is the principle of air openness?
1, the open internal structure is to use the thermal expansion and bending of bimetal to touch the lever, so that the circuit breaker trips to play an overload protection role. Overload protection will have a certain time difference. When a short circuit occurs, the current flows through the induction coil to generate a strong magnetic field, which pushes the lever to make the circuit breaker trip quickly.
2. According to the different protection functions, the release can be divided into overcurrent release and voltage loss release, and there are three release modes: thermal release, electromagnetic release and multiple release.
3. When the line is generally overloaded, the overload current can not make the electromagnetic release act, but it can make the thermal element generate a certain amount of heat, make the bimetal bend upward when heated, push the lever to disengage the hook from the lock catch, disconnect the main contact and cut off the power supply.
4. When the line is short-circuited or the current is seriously overloaded, the short-circuit current exceeds the instantaneous tripping setting current value, and the electromagnetic release generates enough suction force to attract the armature to impact the lever, so that the hook rotates upward around the shaft seat and disengages from the lock catch, and the lock catch disconnects three pairs of main contacts and cuts off the power supply under the action of the reaction spring.