The Belimo LM Series represents a line of direct coupled actuators designed for small zone dampers and VAV units. These actuators utilize brushless DC motor technology and are presented as replacements for rack and pinion type actuators, specifically the LM24. The documentation details installation procedures, electrical specifications, and operational features including adjustable run times and rotation control. The actuators are designed for applications requiring a minimum of 35 in-lb torque and are compatible with existing control systems.
Actuator Overview and Applications
The Belimo LM Series actuators are compact, yet powerful, delivering a minimum torque of 35 in-lb. This makes them suitable for damper areas up to 8 sq-ft, based on a loading of 4 in-lb/ft. Primary areas of application include VAV (Variable Air Volume) units and small zone dampers. The series is presented as a direct replacement for existing Belimo actuators, specifically the LM24, ensuring compatibility with established control systems. Replacement of existing pneumatic actuators may require the use of linkage.
Electrical Specifications and Features
These actuators operate on a 24 VAC/DC power supply. The control signal options include on-off, floating point, and proportional 2 to 10 VDC, offering multi-functionality. Feedback signals are available as 2 to 10 VDC or VDC variable, utilizing either a 10kΩ or 5kΩ feedback potentiometer. The actuators incorporate a brushless DC motor (BDCM) technology. Electrical connections are made via a screw terminal strip and utilize plenum rated 18 GA cable. A built-in auxiliary switch is also included.
Installation Considerations
Installation involves adherence to specific mounting conditions and torque loading guidelines. The documentation highlights the importance of proper damper torque loading, referencing parallel blade configurations without edge seals. The default settings for these actuators include a control signal range of 2 to 10 VDC and a default run time of 150 seconds.
Operational Features and Adjustments
The LM Series actuators offer several operational features and adjustment capabilities. The run time is adjustable, ranging from 75 to 300 seconds. Specific run time ranges are provided for different torque levels: 80 to 110 seconds for 0 to 35 in-lb and 25 to 35 seconds for 0 to 18 in-lb. A left/right rotation switch allows for field adjustment of the actuator’s direction of rotation. Angle of rotation limiting is available both mechanically and electronically. Initialization and overload protection mechanisms are integrated into the actuator’s design. Manual override functionality is also present, allowing for testing and adjustment.
Technical Specifications Summary
The following summarizes key technical specifications based on the provided documentation:
- Torque: 35 in-lb
- Power Supply: 24 VAC/DC
- Control Signal: On-off, floating point, proportional 2 to 10 VDC
- Feedback Signal: 2 to 10 VDC, VDC variable (with 10kΩ or 5kΩ potentiometer)
- Run Time: 95 sec (default), Adjustable 75-300 sec
- Rotation: Adjustable via left/right rotation switch
- Cable: Plenum rated, 18 GA
- Application: VAV Units and Small Zone Dampers
- Damper Area: Up to 8 sq-ft (based on 4 in-lb/ft loading)
Compatibility and Replacement
The LM Series is designed as a direct replacement for existing Belimo LM24 actuators, ensuring compatibility with existing control systems. However, when replacing pneumatic actuators, the documentation notes that linkage may be required. The actuators are also noted as being “Quiet Plus,” suggesting a focus on reduced noise during operation.
Conclusion
The Belimo LM Series direct coupled actuators provide a compact and powerful solution for controlling dampers in VAV units and small zone applications. Key features include brushless DC motor technology, adjustable run times, and flexible control signal options. The actuators are designed for ease of installation and compatibility with existing systems, particularly as replacements for older Belimo models. The provided documentation focuses on installation, electrical specifications, and operational adjustments, offering a technical overview for professionals and informed users.
Sources
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