4000W Industrial AC Variable Speed Controller

Rated for 100–120V AC input. Handles up to 4000W resistive load (e.g., electric furnaces, incandescent lamps) and 1500W inductive load (e.g., angle grinders, marble cutters, blowers, exhaust fans). Continuous current: 9A; maximum current: 15A. Flame-retardant housing resists ignition and retains rigidity at high operating temperatures — verified through sustained thermal testing. Precision-engineered single-turn pressure-regulating knob ensures stable, stepless speed control with minimal calibration drift. Input and output circuits feature dedicated mechanical switches for safe isolation during maintenance or load changes. Compatible with North American Type A and Type B plugs — ready for immediate use. Not suitable for equipment containing printed circuit boards, electrolytic capacitors, switching power supplies or digital controllers (e.g., modern LED lights, battery chargers, or brushless tools). Widely used in fabrication shops, stoneworking, HVAC maintenance and hobbyist workshops where robust, analogue speed regulation is preferred over digital alternatives.