- Ametherm is a leading manufacturer of Power Thermistors. Ametherm offers the highest rated steady state current rating as well as highest rated energy handling capability offered in the market. Their excellent long-term stability and rugged structure makes them ideally suited for limiting Inrush current in the motors (1/3 HP to 3.0 HP range), medical (Power supplies, MRI), Security systems (X-Ray machines), transformers (up to 8.0 KVA), telecom (Power supplies up to 4000 watt out put power) and motor drives, in the most cost effective method.