Hoffman Controls 791-ECM Fan Speed Control ECM VMA

The Hoffman Controls 791-ECM Fan Speed Control ECM VMA adjusts the speed of electronically commutated motors used for air handling. It receive analog signals from temperature sensors or pressure transducers and converts those inputs into pulse-width modulated or analog voltage outputs for the motor. Mounted inside the electrical control cabinet, the controller varies blower rotation as thermal or static pressure conditions change. HVAC systems use this control to regulate airflow through the ductwork while maintaining the required static pressure as load conditions vary. By align motor speed to incoming control signals it provides the variable airflow needed during different stages of air-handling operation.