This kit was designed to control the speed of AC motors with carbon brushes, anything from drills to saws to vacuum cleaners. Unlike other circuits such as normal dimmers the kit performs a phase cut only once per period. The moment of cutting determines the speed, which can be adjusted from 5% to 95%.
The kit provides high torque even at low speeds. RFI is suppressed to eliminate noise and interference. The circuit controls both low voltage (from 24VAC to 240VAC at 5.5A) AC motors and mains voltage (110VAC or 220VAC) loads.
The supply and load circuits are electrically isolated from each other for safety and reliability. The control circuit is powered by the mains, but the load supply may be derived from a different AC source. Both voltages should be the same frequency and the same phase or opposite phase.