MEP-7851 | Actuator: Tri-State, Failsafe, 24VAC/VDC, 320 in-lbs

These powerful, efficient, durable, direct-coupled actuators provide tri-state or proportional control for large control air dampers or valves in HVAC systems. A minimum torque of 180 or 320 in-lb. is available over the 94° angular rotation. Capacitor-driven fail-safe models provide durable, efficient operation with switch-selectable fail direction.

The proportional actuator models accept a 0–10 VDC, 2–10 VDC, or 4–20 mA control signal input from a thermostat, controller, or building automation system. “Anti-jitter” circuitry significantly reduces hunting and needless wear on the actuator and valve packing or damper components (from unnecessary miniscule position changes caused by undamped analog input signals). A user-initiated, auto-mapping feature provides more precise equipment control by reassigning the (0–10 VDC, 2–10 VDC, or 4–20 mA) input signal range over a reduced rotation range (from 45° to 94°). Proportional input models also feature a switch-selectable, voltage feedback output that is proportional to the actuator position. With the 0–10 VDC input, feedback options are 0–5 or 0–10 VDC, and with 2–10 VDC or 4–20 mA inputs, feedback options are 1–5 or 2–10 VDC.

The tri-state models are designed for use with floating thermostats, controllers, or building automation systems. They feature an optional 10K ohm (±10%), three-wire potentiometer feedback output. Fail-safe models also allow two-position control as well.

All actuators mount directly on 3/8″ up to 1.05″ round or 5/16″ up to 5/8″ square shafts, eliminating the need for expensive and complicated linkages. A non-rotation bracket, to prevent lateral movement, is included with each actuator. A gear disengagement button allows manual positioning of the damper and/or gear train without energizing the actuator. Removable terminals and 1/2″ NPS conduit fittings make wiring easier. The actuators are protected against overloading and do not require end or limit switches.

(If lower torque is required, see also the MEP-4200/4500/4900 series.