Douglas Randall R40D Proportional Controller Solid State Relay is a 40 A maximum-load device with a 480 VAC coil input, designed for precise proportional control of electrical loads in industrial and commercial settings. Built around a solid-state relay, the R40D provides reliable power regulation for higher-current circuits that require consistent switching behavior. Model R40D from Douglas Randall is documented as a single-unit, 40 A, 480 VAC-coil proportional controller.
