The control protective switch is composed of several parts, and some components can be added according to the requirement. Its function is to eliminate the surge voltage and interference signal in the power, so that it can improve the quality of the power supply. The fuse tube can be fuse when the circuit is short circuited, so that the damage can be avoided and the damage is enlarged. But now there are many varistors, the resistance function is in normal voltage without any effect and has no effect, once the voltage is too high will produce effect, is to fuse tube.

Insurance is the control and protection of a switch element is very important, when the failure of products we should observe the power supply pipe there is no insurance damage occurs, once found the insurance tube has been damaged, could not immediately rush to replace. First see if the power supply is short circuited. This check you need to prepare a multimeter to test the resistance profile, normal resistance should be in the tens of ohms above, if the resistance of the 0 tells us there is a short-circuit fault. Beyond this point, we should also focus on the AC filter capacitor of the power supply. If there is a varistor, we need to check this item. These are the location and cause of the malfunction of the control and protection switch, so check these parts first.

If the control and protective switch for fire protection, fire type products in the line will have fault alarm, this time if we want to overhaul it must be operating knob to solve again buckle position after the alarm signal can be. When you continue to use it, just turn the knob to the point where it is connected so that it can act as an alarm.