Fusible wirewound safety resistor

Jon Lawson

Vishay Intertechnology introduced a new 1W axial cemented, fusible wirewound safety resistor that delivers safe and silent fusing operation during overload conditions, while withstanding pulse voltages of at least 2 kV (1.2/50µs) per IEC 61000-4-5 for resistance values ≥75Ω.

The Vishay Draloric AC01..CS combines a fusing time of < 30 s for a 32W overload with a special nonflammable silicon cement coating for immediate interruption without flame and explosion when AC mains voltage (110 VAC / 230 VAC) is applied. Typical applications include electric appliances, energy meters, and power supplies.

The device released today is specially designed to meet UL1412 safety requirements (formal approval pending). In addition to fusing ‘without a bang’, the AC01..CS acts as an inrush current limiting resistor during normal operation. The safety resistor's specially developed lacquer coating has superior thermal and electrical insulating properties. This allows designers to meet safety requirements more easily, while eliminating the need to put additional fuses in series with the input resistor.

The AC01..CS provides a power rating of 1.1 W at an ambient temperature of 40 °C and 1.0 W at 70 °C. The RoHS-compliant device offers resistance from 3 Ω to 100 Ω, resistance tolerance of ± 5%, and temperature coefficient of resistance (TCR) of ± 200 ppm/K.