1. Fan Assembly Driven by Magnetic Fields
Senior Design Project – Fall 2013

2. Introduction Problem Statement
In some operating environments, it can be desirable to rotate a fan without directly contacting the fan. For example, it may be desired to position a fan in an environment that is inhospitable to a motor, such as a high temperature environment.

3. Introduction Proposed Solution
Magnetic fields are generated by permanent magnets and electromagnets. Numerous variations of motors exist that apply different configurations of positioning permanent magnets relative to electromagnets to capitalize on the resulting repulsive magnetic forces. Our proposal applies these principles to drive a fan in rotation.

4. Background Information
Current solutions to the problem:
Remote motor-driven fans
Motor-driven fans are positioned at location remote from the precise position at which flow inducement is desired. This can compromise the efficiency of the system since the fluid must be forced to move over a greater distance.
Heater Technology
Heat is directed to the fluid with the hope of inducing desired flow. This approach is unreliable.

5. Project Objectives Electromagnetics Technology Air Flow User Controls
Feedback Control

6. Overview of Project Modules Power Supply Microcontroller
Current Amplifier
LCD
Electromagnetic Coil

7. Power Supply Purpose Design
Convert 120 VAC, at 60 Hz, to 5 VDC and 12 VDC
Make the system operable to be powered by a standard American outlet
Power the electronics of the system
Design
Influenced by IEEE Standard
Step-down transformer
Full bridge rectifier
Filter
Voltage regulator

8. Power Supply
Schematic

9. Microcontroller Purpose Design Control the logic of the system
Control LCD
Interface the switches and sensor
Design
Microchip PIC18F46K44
16 MHz Oscillator speed
36 I/O pins
Internal AD and DA converters
Program Memory: 64k (bytes flash)
Data Memory: 3896 (bytes SRAM)
EEPROM: 1024 (bytes EEPROM)

10. Microcontroller
Schematic

11. Microcontroller Microcontroller Software
Initialize pins to desired configuration
Algorithm to determine rpm
Logic to actively monitor and display status of the system
Logic to display various user menus
Allows for three different run times and three different speed options
Allows the user to terminate operation of the system at any time

12. Microcontroller
Microcontroller Software
Sample Code:

13. Current Amplifier Purpose Design
Drive the output load (the electromagnetic coil)
Convert 0 – 5 V input signal to 0 – 5 A.
A buffer between the Microcontroller and the output load
Design
TI-OPA549 Operational Amplifier
High current, high voltage amplifier
Gain of 2
Powered by 12 VDC

14. Current Amplifier
Schematic

15. LCD Purpose Design To communicate with the user
To facilitate user control
To display current system status
Design
Based on Hitachi HD44780
4 X 20 display
Communicates with Microcontroller by the serial port

16. LCD
Pin out:

17. Electromagnetic Coil Purpose:
Generate a magnetic field to interact with a magnetic field generated by a permanent magnet mounted on a fan blade.
Induce repulsive interaction between the magnetic fields.
Maintain a fixed magnetic field to repulse the magnetic field generated by a permanent magnet mounted on the moveable fan blade.
Impose movement of the fan blade and rotate the fan.

18. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

19. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

20. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

21. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

22. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

23. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

24. Electromagnetic Coil Design First Design:
Circular Coil Assembly surrounding the Fan

25. Electromagnetic Coil Design First Design Failure: Blades did not move
Applied 1 – 5 A of current through the coil assembly.
Observed extremely low magnetic field from the wires of the coil assembly.
Did not test with Gauss meter, but filings sprinkled on the coil did not stick to the wires of the coil assembly.

26. Electromagnetic Coil Design Second Design:
Coil wrapped around a rod positioned transverse to the blades.

27. Electromagnetic Coil Design Second Design Failure: Blades did not move
Applied 1 – 5 A of current through the coil assembly.
Observed a stronger magnetic field from the electromagnet relative to the first design, but still relatively weak.
The magnetic field generated by the permanent magnet over-powered the field induced by the current running through the coil.

28. Electromagnetic Coil Design Prospective Action
We will build a simple DC motor to allow the project to progress.
We will further analyze the failures of the first two designs to determine if a third design can be constructed and tested in the available time.

29. Work Completed Power Supply Microcontroller hardware LCD hardware
Successfully output 12VDC and 5 VDC
Microcontroller hardware
Successfully interfaced all switches and Hall Effect sensor
LCD hardware
Successfully interfaced with the Microcontroller
Displays multiple menus
Board Layout
All components mounted on a single board
Current Amplifier
Successfully converts voltage to current

30. Plans to Complete the Project
Build a simple DC motor
The motor will allow us to test and fine tune the other modules.
Implement Sensor for Feedback Controls
Monitor Rotation
Finalize Control Logic
Add Timer and Speed Controls
Finalize Enclosure
Mount Board and LCD together in single enclosure

31. Conclusions Overview of Project Goal
Build an electromagnetically- propelled fan having a high- level of user control.
Summary of Completed Work
Power Supply
Microcontroller hardware
LCD hardware
Board Layout
Current Amplifier
Final expectations for the project
We expect all modules to be functioning as desired, except the electromagnetic coil assembly.