The Slave Damper Control Relay (SDCR) is a relay control panel used when three or more dampers need to be controlled by a single switch or thermostat. The SDCR can control up to four dampers. If more than four damper motors need to be controlled, multiple SDCR relay panels can be wired together to control as many dampers as necessary. Each motor is controlled individually by a separate set of contacts in the plug-in relay. Each SDCR requires an individual 24 volt, AC, 40 VA transformer to power each set of damper motors.