Browsing by Author "Dr. Larry M. Silverberg, Committee Chair"

Now showing 1 - 3 of 3

Control of HVAC Dampers by Trans-Permanent Magnetics
(2005-11-09) Webber, David Wayne; Dr. M. K. Ramasubrmanian, Committee Member; Dr. Larry M. Silverberg, Committee Chair; Dr. Gracious Ngaile, Committee Member
In recent years, the nation has come under an energy crunch. The energy crisis is in part due to inefficient energy use in actuators. Recent advancements in trans-permanent magnetics, will allow this new technology to be employed in actuators that will require significantly less energy. Applications such as spacecraft pointing and deployment, along with air valve actuation have already proven feasible. The applications for trans-permanent magnetics vary from solenoids to motors, with evident benefits of low power, and no wear. The purpose of this research is to develop and implement a trans-permanent magnetic actuator for HVAC dampers. The system will use a minimal number of magnets and will utilize magnetic forces for soft latching of the device in it open and closed states. The scope of this project includes mounting an HVAC damper in a moderate air stream, the design of a trans-permanent actuator, and evaluation of the actuator. The air flow through the duct is higher than typical found in residential or commercial HVAC systems. The actuator will rely upon onboard magnetization to operate the damper's louvers. The onboard magnetization process will occur through an impulse magnetizing circuit. Several experimental tests were conducted on the prototype actuator to test performance and limitations. The results of these experiments demonstrate a working unoptimized trans-permanent magnetic actuator.
Design and Manufacture of a Second Generation Switch-operated Window Wall
(2006-09-07) Butterfield, Matthew Paul; Dr. Larry M. Silverberg, Committee Chair; Dr. Mohammed A. Zikry, Committee Member; Dr. M. K. Ramasubramanian, Committee Member
A new system of horizontal window blinds that operates by means of electrostatic induction, called the powerblind, was developed at North Carolina State University. The blinds can be opened and closed with a simple switch. An evaluation of the first-generation system was conducted to determine the features that needed improvement before a second-generation model could be constructed. The problems inherent to the previous powerblind model were resolved after redesigning several parts. Eight new, fully operational powerblind units were assembled and installed in a boardroom of the Talley Student Center at North Carolina State University in July 2006. They replaced the defective first-generation units previously located in the boardroom. A set of instructions for all the assembly and manufacturing processes was also created to facilitate the construction of additional second-generation windows. With the improvements made to the design and to the manufacturing process, it was concluded that commercial production would be possible at this stage of the project. The powerblind windows remain cost effective, when compared to the combination of standard window blinds and insulated glass. The ability to quickly and easily control the amount of light entering a room makes these windows desirable for many applications.
Trans-Permanent Magnetic Actuation
(2003-09-08) Farmer, Daniel J; Dr. G.D. Walberg, Committee Member; Dr. E.C. Klang, Committee Member; Dr. E.N. Chukwu, Committee Member; Dr. Larry M. Silverberg, Committee Chair
The demands for an actuator to deploy, position and shape large spaced-based structures form a unique set of design criteria. In many applications it is desirable to hold displacements or forces between two points to within specified requirements (the regulation problem) and to periodically to change position (the tracking problem). Furthermore, the interest generally lies in satisfying the dynamic performance requirements while expending minimal power, while meeting tight tolerances and while experiencing little wear and fatigue. The actuator must also be able to withstand a variety of operational conditions such as impacts and thermal changes over an extended period of time. Current trends in large-scale structures have addressed the demands by using conventional actuators and motors, along with elaborate linkages or mechanisms to shape, position, protect and deploy. The developed designs use unique characteristics of permanent magnets to create simple direct-acting actuators and motors very suitable for space based structures. The developed trans-permanent magnetic (T-PM) actuators and motors are systems consisting of one or more permanent magnets, some of whose magnetic strengths can be switched on-board by surrounding pulse-coils. The T-PM actuator and motors expend no power during regulation. The T-PM can periodically change or remove the strength of its own magnets thereby enabling both fine-tune adjustments (microsteps) and large-scale adjustments (rotation). The fine (microstep) adjustments are particularly helpful in thermally varying space environments. The large-scale adjustments (rotation) are particularly helpful in deployment where the structure or antenna must experience large-angle rotations and/ or large displacements. T-PM concepts are illustrated in direct acting actuators and built into stepper motor and permanent magnet motor applications. Several examples of design, analysis and testing are developed to verify the technology and supporting equipment. Also discussed is the convergence of technology that has made this technology timely and practical.