SURGE PROTECTION DEVICE AND SURGE PROTECTOR USING SAME

PROBLEM TO BE SOLVED: To provide a small sized, highly reliable and inexpensive surge protection device (SPD) SPD with a comparatively simple structure, and a surge protector using the same. SOLUTION: In the surge protection devices SPD 40-1, 40-2, a gas arrestor 41 is connected in series with a varistor group wherein a plurality of high resistance varistors 42-1 to 42-5 are connected in parallel with each other, furthermore a resistor 43 is connected between the opposite electrodes of the varistor group. Since the varistor voltage is set higher than the peak value of AC power supply voltage, normally the varistors 42-1 to 42-5 are insulated from the power source circuit with the gas arrestor 41. The operation voltage of the varistors 42-1 to 42-5 is set higher than the peak value of the AC power supply voltage to interrupt the energization of the AC power current, when an abnormal voltage is entered. The electric charge charged in the varistors 42-1 to 42-5 is quickly discharged via the resistor 43 to prevent the re-ignition of the gas arrestor 41. COPYRIGHT: (C)2008,JPO&INPIT