In the main circuit of AC motor, fuse can be used as short circuit protection, can it play the role of overload protection at the same time, why?
Therefore, the overload protection of the motor requires the use of a thermal relay that can accumulate heat effects. When the accumulated heat reaches a certain degree, the protection is started, and the motor is not allowed to continue heating up.
If the current of the motor is working normally is 10A, if there is a fuse that can work stably in the case of 10A, the case of 11A will be blown. So because the motor load for a short period of time (a few seconds) suddenly become larger, up to 12A, and then returned to normal, it is not to endanger the safety of the motor (motor temperature rise, not what) without the need for protection, but the fuse has melted. That's what we don't want to see.
The fuse can not play the role of overload protection.
Short circuit protection: some devices can monitor abnormal conditions in the work circuit (such as short circuits). When abnormal happens, the circuit is cut off and alarm is sent to prevent further expansion of the damageA typical short circuit protection is a fuse. When the short circuit is short, the current is very high. When the fuse is blown, the circuit will be out of power.Overload protection: to prevent the main power line from overload protection caused by overheating damage and installation of overload protection equipment
