Boston Gear RB3R is a Ratiotrol DC motor speed controller designed for 1–2 HP DC motors in industrial automation. It accepts 115/230 VAC input at 50/60 Hz and provides 50/90 VDC output to the motor, with a listed current draw of 10.5/11.6 A. This controller belongs to Boston Gear’s legacy Ratiotrol line, offering reliable speed control for medium‑duty DC drives in equipment where adjustable motor speed is needed.
