High-voltage current-limiting fuses are used to protect electrical equipment and connecting wires. They operate by heating the fuse element when the current flowing through the equipment exceeds the maximum allowable current. If a high-voltage current-limiting fuse blows, the cause should be identified, corrected, and then replaced with a new fuse.Do not use wires in place of fuses, as this can easily expand the scope of the fault. Modern vehicles typically combine multiple high-voltage current-limiting fuses and install them near the instrument panel. The contact between the fuse and the bracket must be very reliable. Poor contact increases contact resistance and reduces voltage. The fuse can easily overheat and blow, causing undervoltage in electrical equipment and affecting normal operation. A blown high-voltage current-limiting fuse can usually be detected visually.For more hidden faults, you can use the resistance range of a multimeter to measure. Loose brackets should be riveted tightly, and if there is oxidation or rust, use sandpaper to clean it to maintain good contact.

The basic working principle of a high-voltage fuse is to control an electronic switching element with a variable on/off time ratio to convert DC power into pulsed AC power. The amplitude of the pulsed AC power is then transformed as required by energy storage elements or transformers. After rectification and filtering, it is converted into the required DC voltage. When a fault occurs in the circuit, the high-voltage current-limiting fuse will automatically disconnect the circuit to protect the electrical appliance.

In the self-excited type, the circuitry controlling the switching signal and the pulse power output circuit are separate. Essentially, a high-voltage fuse type uses an oscillator to generate pulses with a variable on/off time ratio, which are then amplified. The self-excited type combines oscillation and amplification. The self-excited type is the most commonly used in practice and also utilizes high-voltage current-limiting fuses for protection.