Actuator with modular fail-safe assembly

A modular fail-safe assembly for actuators, comprising:

• a return mechanism;
• and
• a housing configured to house the return mechanism and support modular interfacing with a non-fail-safe actuator, wherein the return mechanism is configured to implement a fail-safe operation in the non-fail-safe actuator in response to power failure or control signal failure, wherein the return mechanism is configured to be removably coupled to the modular fail-safe assembly.

An actuator system for use in a heating, ventilating, or air conditioning (HVAC) system to drive a movable HVAC component, the actuator system comprising:

• one or more fail-safe assemblies provided as modular attachments;
• and
• a modular actuator configured to support modular interfacing with the one or more fail-safe assemblies, the one or more fail safe assemblies being removably coupled to the modular actuator, wherein in response to power failure or control signal failure, a fail-safe assembly, of the one or more fail-safe assemblies, is configured to implement a fail-safe operation that drives the movable HVAC component to a fail-safe position.