Johnson Controls S66AA-1 Electronic Fan Speed Control 24V

The Johnson Controls S66AA-1 Electronic Fan Speed Control is designed to provide accurate and energy efficient control of airflow in HVAC systems. This is a small panel mount fan speed control device that uses a 0 to 10 VDC electrical signal from a building automation system. It operates at a standard voltage of 24 VAC and has two (SPDT) relay contacts. These relays act as switches where they turn ‘ON’ and ‘OFF’ the fan motor. The S66AA-1 modulates fan speed by converting electrical signal into proportional changes in the relay contact switching.