For modulation or On/Off control of dampers in HVAC systems. Actuator sizing should be done in accordance with the damper manufacturerâ€™s specifications. The actuator is mounted directly to a damper shaft from 1/4â€ up to 1/2â€ in diameter by means of its universal clamp, 1/2â€ shaft centered at delivery. A crank arm and several mounting brackets are available for applications where the actuator cannot be direct coupled to the damper shaft. Control is floating point from a triac or relay, or On/Off from an auxiliary contact on a fan motor contactor, controller, or manual switch.
The TF series actuators provide true spring return operation for reliable fail-safe application and positive close-off on air tight dampers. The spring return system provides consistent torque to the damper with, and without, power applied to the actuator. The TF series provides 95Â° of rotation and is provided with a graduated position indicator showing 0 to 95Â°. The TF24-3(-S) US uses a brushless DC motor which is controlled by an Application Specific Integrated Circuit (ASIC) and a microprocessor. The microprocessor provides the intelligence to the ASIC to provide a constant
rotation rate. The ASIC monitors and controls the brushless DC motorâ€™s rotation and provides a digital rotation sensing function to prevent damage to the actuator in a stall condition. The actuator may be stalled anywhere in its normal rotation without the need of mechanical end switches. Power consumption is reduced in holding mode. The TF24-3-S US version is provided with 1 built-in auxiliary switch. This SPDT switch is provided for safety interfacing or signaling, for example, for fan startup. The switching function is adjustable between 0Â° and 95Â°. The auxiliary switch in the TF24-3-S US is double insulated so an electrical ground is not necessary.