The Belimo LM Series comprises direct coupled actuators designed for damper control in HVAC systems. These actuators utilize brushless DC motor technology and are suitable for VAV units and small zone dampers. The documentation details installation procedures, electrical specifications, and operational features, including manual override and adjustable run times. The LM Series is presented as a replacement for rack and pinion type actuators, specifically offering compatibility with existing LM24 control systems.
Actuator Overview and Applications
The Belimo LM Series actuators are characterized by their compact size and ability to deliver a minimum of 35 in-lb of torque. This makes them appropriate for damper areas up to 8 sq-ft. Primary areas of application include variable air volume (VAV) units and small zone dampers. The actuators are designed as direct replacements for existing Belimo actuators, streamlining the upgrade process for compatible systems. The documentation highlights the LM Series as a replacement for rack and pinion type actuators, offering a direct coupled alternative.
Installation Considerations
Installation of Belimo AM actuators requires attention to mounting conditions and damper torque loading. The documentation emphasizes the importance of proper torque loading, particularly for parallel blade dampers without edge seals. Specific details regarding damper torque loading are provided, though the documentation does not elaborate on calculation methods or specific damper types beyond this general guidance.
Electrical Specifications and Features
The LM Series actuators operate on a 24 VAC/DC power supply. They support multiple control signal types, including on-off, floating point, and proportional 2 to 10 VDC signals. Multi-function capabilities are also noted, though the specific functions are not detailed in the provided documentation. Feedback signals are available as 2 to 10 VDC or a variable VDC signal, utilizing either a 10kΩ or 5kΩ feedback potentiometer.
The actuators incorporate a brushless DC motor, contributing to quiet operation. Electrical connections are made via a screw terminal strip, and the actuators are equipped with plenum rated cable, 18 GA. A built-in auxiliary switch is also included. General wiring diagrams are referenced, with further details available on page 169 of the referenced documentation.
Operational Characteristics and Adjustments
The standard run time for the LM Series actuators is 95 seconds. However, the run time is adjustable within a range of 75 to 300 seconds. Different torque ranges correspond to varying standard run times: 80 to 110 seconds for 0 to 35 in-lb and 25 to 35 seconds for 0 to 18 in-lb.
Actuators feature a left/right rotation switch, allowing for adjustment of the direction of rotation during testing and installation. Both mechanical and electronic angle of rotation limiting are incorporated into the design. The documentation references start-up and checkout procedures, with further details available on page 171.
Compatibility and Replacement
The LM Series actuators are designed to be compatible with existing control systems, specifically identified as replacements for LM24 actuators. This compatibility simplifies the upgrade process, minimizing the need for extensive system modifications. The documentation also notes compatibility with Warren Technology Quiet Plus VAV terminal units, where the actuator directly couples to the VAV bypass damper shaft. Existing pneumatic actuators may require linkage for proper operation.
Technical Specifications Summary
The following specifications are derived from the provided documentation:
- Torque: 35 in-lb (minimum)
- Power Supply: 24 VAC/DC
- Motor Type: Brushless DC
- Control Signal: On-off, floating point, proportional 2 to 10 VDC, Multi-function
- Feedback Signal: 2 to 10 VDC, VDC variable
- Feedback Potentiometer: 10kΩ, 5kΩ
- Run Time: 95 sec (standard), Adjustable 75-300 sec
- Cable: Plenum rated, 18 GA
- Damper Area: Up to 8 sq-ft
Manual Override and Initialization
The documentation references manual override functionality, allowing for direct control of the actuator independent of the control system. The initialization process is not detailed in the provided documentation. The presence of a direction of rotation switch facilitates testing and adjustment of the actuator's operation. Overload protection mechanisms are incorporated into the design, though specific details regarding these mechanisms are not provided.
Safety and Compliance
The documentation does not contain specific safety warnings or compliance certifications. However, the use of plenum rated cable suggests adherence to relevant building codes regarding air handling spaces. Further safety information would be available in separate documentation not provided in the source material.
Conclusion
The Belimo LM Series direct coupled actuators offer a compact and powerful solution for damper control in HVAC systems. Their compatibility with existing LM24 systems and Warren Technology VAV units simplifies installation and upgrades. Key features include brushless DC motor technology, adjustable run times, and multiple control signal options. The documentation provides essential information for installation, operation, and troubleshooting, though further details regarding specific functions and safety procedures would require consulting additional resources.