The 5 Step Auto Transformer Three Phase 14 Amp controller provides precise multi-step speed regulation for commercial fans. Designed for use with HOT SPOT protected fans, it removes the need for a separate starter and ensures reliable performance. Featuring a compact, fire-retardant surface-mounted enclosure, it minimizes motor noise with no magnetic hum. Additional terminals allow for connection of remote switching devices and anti-freeze thermostats, making it a flexible and efficient solution for commercial ventilation systems. Stock reference: RD14.