Honeywell Modutrol IV Series 41 and 81 rotary actuators are rugged spring‑return motors used for precise damper and valve control in HVAC, burner safety systems, and industrial applications. Series 41 operates on line-voltage (e.g., 120 VAC), while Series 81 uses low-voltage (24 VAC), both offering reliable torque and fail‑safe return during power loss.
Honeywell Modutrol IV Series 41 (line-voltage) and Series 81 (low-voltage) spring-return actuators provide heavy-duty two-position fail-safe control for commercial dampers, industrial burner firing rates, and globe valve assemblies. Because choosing the right model requires verifying power supply requirements (24VAC vs. 120VAC/240VAC), torque ratings (25 lb‑in or 60 lb‑in), stroke timing, and internal auxiliary switch options, verifying technical specs is essential. Contact our technical sourcing team today to locate your exact replacement or cross-reference legacy models.
Series 41 and Series 81 motors feature NEMA 3 die-cast aluminum housings, oil-immersed gear trains, and mechanical spring-return mechanisms designed for maximum fail-safe reliability. Use this matrix to compare operating voltages, torque classes, and common part configurations.
| Actuator Class | Voltage & Control Logic | Common Series |
|---|---|---|
| Series 41 (Line Voltage) | 120VAC or 240VAC two-position (SPST/SPDT) line-voltage spring-return motors providing 25 lb‑in or 60 lb‑in fail-safe torque output. | M4184A1002, M4185A1001 |
| Series 81 (Low Voltage) | 24VAC two-position spring-return motors engineered for low-voltage safety interlocks, fresh air dampers, and fuel cutoff valves. | M8184A1003, M8185D1006 |
| Auxiliary Switch Models | Includes integral SPDT internal microswitches for end-of-stroke position feedback, burner interlocks, or equipment staging. | M8185D1014, M4185D1002 |
Line-Voltage Two-Position Fail-Safe Damper Assembly
Low-Voltage Spring-Return Burner & Valve Package
Voltage & Spring-Return Orientation Alert: Never supply 120V line voltage to a Series 81 motor (24V), as this will immediately destroy the internal field coil. Additionally, because Modutrol IV motors feature dual-ended shafts, spring-return orientation (fail-closed vs. fail-open) depends on which shaft end is attached to your linkage—verify rotation prior to mounting.
Honeywell Series 41 and Series 81 Modutrol IV motors remain the industrial standard for applications requiring dependable two-position fail-safe action. Whether managing outside air intake dampers or fuel cut-off valves on commercial boilers, their internal mechanical heavy-duty spring ensures positive return to the safe position upon power loss.
Featuring quick-connect terminal strip wiring, dual slotted/tapped shaft ends, and field-adjustable stroke potentiometers (adjustable from 90° up to 160°), Series 41 and 81 motors offer seamless replacement across legacy HVAC installations.
Unsure of your voltage rating, spring-return orientation, or torque requirements?
Take a snapshot of your existing motor nameplate, damper linkage layout, or control schematics, and our sales team will confirm the perfect match.
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