Ametherm AS32 5R020

The AS32 5R020 inrush current limiting thermistor from Ametherm offers a maximum steady state current of 20A (up to +25°C) and a resistance of 5Ω ±25% (at 25°C). The Ametherm AS series are designed to withstand high steady-state current and input energy. Compared to traditional inrush current limiters, the devices offer lower current density, faster reset times, and a wider temperature range without derating. This lower current density, in combination with a uniform temperature gradient throughout the disc, increases reliability by eliminating hot spots from fatigue. The AS series from Ametherm are suitable for high energy and short term high current applications.

• Inrush current limiting thermistor
• Resistance of 5Ω (at 25°C)
• Maximum steady state current of 20A (up to +25°C)
• Maximum recommended energy of 300J
• Voltage ratings of 120VAC, 240VAC, 440VAC and 680VAC
• Actual energy failure at 600J
• 0.03Ω at 100% maximum current and 0.06Ω at 50% maximum current
• Body temperature of +215°C at maximum current
• Material type B (for beta and curve)
• Tolerance ±25%
• Dissipation constant of 78.2mW/°C
• Thermal time constant of 0mW/s
• Recognised by Underwriters Laboratories (UL) for ensured safety

Typical applications for the AS series include:

• Protection of pre-charge circuits in lithium ion batteries
• Variable-frequency drives in sports equipment like treadmills, high-speed computers and processors
• Switch mode power supplies for plasma cutters, welders, audio amplifiers, MRIs and x-ray machines

The below table gives the full specifications of the Ametherm AS32 5R020 series: