Ametherm MS32 5R020

The MS32 5R020 inrush current limiting thermistor from Ametherm offers a maximum steady state current of 20A (up to +65°C), resistance of 5Ω ±25% (at 25°C) and a maximum recommended energy rating of 300J. Ametherm’s MegaSurge™ series of inrush current limiting NTC thermistors reduce costs and greatly simplify designs. In addition, they increase safety by eliminating the fire hazard associated with failed relays. While traditional thermistors are only certified for input voltages from 85 V_AC to 265 V_AC, UL recognised MegaSurge™ devices are certified for single and three phase input voltages up to 480 V_AC. These specifications are the highest of any single-solution inrush current limiting device on the market.

• Inrush current limiting thermistor
• Resistance of 5Ω (at 25°C)
• Maximum steady state current of 20A (up to +65°C)
• Maximum recommended energy of 300J
• Voltage ratings of 120VAC, 240VAC, 440VAC and 680VAC
• Actual energy failure at 670J
• 0.04Ω at 100% maximum current and 0.10Ω at 50% maximum current
• Body temperature of +204°C at maximum current
• Material type G (for beta and curve)
• Tolerance ±25%
• Dissipation constant of 55.4mW/°C
• Thermal time constant of 194s
• Recognised by Underwriters Laboratories (UL) for ensured safety

Typical applications for the MS32 series include:

• Inrush current protection of power supplies
• Motor controllers, Audio amplifiers, Battery chargers and Frequency generators,
• Plasma cutting tools, MRI machines and Toroidal transformers

The below table gives the full specifications of the Ametherm MS32 5R020 series: