What is A Semiconductor Fuse?

A Semiconductor fuse, also known as the ultra-rapid fuse, high-speed fuse, or rectifier fuses; a Semiconductor fuse, is a high-speed current-limiting fuse that is designed to protect and isolate sensitive semiconductor components such as diodes, thyristors, SCRs, etc. by minimizing the I²t, peak current let-through, and arc voltage. Semiconductor fuses generally range from 125 to 2,100 volts and are available in a wide variety of shapes and sizes.

Semiconductor Fuse Classes

Semiconductor Fuses fall into three classes, which characterise the breaking (interrupting) characteristic of the fuse: aR, gR, and gS. These fuse speed markings are often printed on the fuse to help you identify it. Typical applications for semiconductor fuses include the protection of semiconductors (diodes, thyristors, trials, etc) used in power rectifiers, UPS, converters, motor drives (AC and DC), soft starters, solid state relays, photovoltaic inverters, welding inverters, and any application where it is necessary to protect semiconductor devices.

• aR Class Fuses

A R-class fuse only provides partial-range breaking capacity (short-circuit protection only) for the protection of power semiconductors (IEC Utilization category). Note: aR fuses are often faster (with a lower I²t value) than a comparable gS or gR fuse. An aR class fuse must not be used as a replacement for a gR class fuse.

• gR Class Fuses

gR class fuses provide full-range breaking capacity (overload and short-circuit protection) for the protection of semiconductors, cables, and all switchgear of the installation. Designers can often substitute a gR class fuse for an aR class fuse.

• gS Class Fuses

GS class fuses are very similar to gR class fuses. They both provide full-range breaking capacity (overload and short-circuit protection), but gS class fuses have lower power dissipation than gR class fuses due to tighter melting gate values. This also results in GS class fuses having lower fuse body temperatures.