Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Human Generated Power for B9 Better Water Maker P13417 Introduction to the Team Team Members: Guides: Vincent Burolla Leo Farnand Kreag Bradley ISE Diane Kang ISE Emily Belonga ME Nicholas Higgins ME Jordan Lahanas EE Customer: Trang Pham EE B9 Plastics Table of Contents • • • • • • • • • Project Overview Problem Statement Customer Needs Specifications Current Design Testing Preliminary Concepts Concept Selection Conclusions Project Overview • B9 Plastics: A not for profit organization dedicated to social and environmental improvement through the use of certain materials (plastics). • Better Water Maker (BWM): A water treatment device used in the developing world to kill water microbes by using ultraviolet light. The device uses a human powered crank to generate power for the device at 12v. Problem Statement • Our project, in conjunction with B9 plastics, is to redesign the power generator to ease the use of this device for women and children. The current design seems to be too physically demanding to maintain the proper power output for the time required to cleanse a moderate amount of water (over 1 gallon). Customer Needs Specifications V02 Testing Current Design Current BOM Current BOM Preliminary Concepts Concept Selection • New Gear Box • To obtain better gear ratio • Maintain/reuse all electrical work • Motors still experience same input rpms • New Motors • • • • To obtain better gear ratio Ease cost Reduce losses due to friction Significant increase in total lifetime Goal: Each proposal is to decrease input crank rpms *Both proposals include using legs/feet to pedal generator Maximum allowable leg force required to power generator • Current generator requires 50in*lbs of torque to maintain required rpms • Equates to 9 lbf at crank arm handle which is 40% of maximum arm force of women (21 lbf) • Maximum leg force of average woman is 63 lbf • Allowable force = 40% of 63 lbf • 25 lbf experienced at crank arm handle (pedal) New Gear Box Comparison Current New Gear Box Design New Gear Box Torque Equations Basic Stress and Deflection Analysis of Crank Arm Current Design • Large Gear with 9 lbf applied to crank handle Type: Value: Apply normal force 4.11 lbf Ultimate Strength of “Harbec plastic” is 10,700psi Proposed Design • Large Gear with 25 lbf applied to crank handle (pedal) Current Crank Arm • 9 lbf applied Current Crank Arm • 25 lbf applied Gear Small Radius • 25 lbf applied to crank arm pedal Proposed Gear Box Proposed Generator Cover Proposed Generator Cover DRW Proposed Motor Mount Box Proposed Motor Mount Box DRW Proposed New Gear (Small Radius) DRW Proposed New Gear (Large Radius) DRW Proposed Steel Axle DRW Proposed Crank Arm Pedal DRW New Gear Box Current Motor • Mabuchi RS-555PC • Short lifetime • <6000 hours Mabuchi RS-555PC New Motor • CF Motor RS-390PH • Brushed motor • Longer lifetime • More efficient • 4 of these motors in a configuration with 2 parallel • Desired voltage/power of 12 V/17 W • Desired RPMs of ~1650 Proposed Changes • Reverse diode across inductor • Incentive: circuit integrity • Currently the circuit contains an inductor near the input that has no alternative current path, should the transistor in series with it turn off • Adding a reverse diode in parallel with this inductor ensures a discharge path for this current • Replacement of potentiometer by low tolerance resistors • Incentive: cost • The current circuit uses an op-amp comparator and a 5V reference to control powering of a power LED • This LED turns on when a sufficient voltage is generated (>12 V) Pump Circuit • Existing Pump Circuit • Accepts a variable input voltage • 12 V/19 W required to power the ballast and pump • After 10 seconds, pump will activate, moves water through device Proposed Changes • Smoothing RC network (“electrical flywheel”) • Incentive: efficiency, easiness of use • Add smoothing smoothing RC network for charge storage • The time allowed for not cranking the generator and keeping the pump on was decided to be 1.0 seconds • Time constant • This time constant can be achieved with a 100 µF effective capacitance and a 135 kΩ effective resistance. Motor Alternative BOM Motor Alternative BOM Seat Design Proposal • Preliminary concepts: Proposed Seating Position Assembly Proposed Seating Position Assembly (Hidden Lines View) Proposed Plywood Insert Geometry DRW Proposed Seat Back Rest DRW Proposed Bucket Seat DRW Entire proposed gearbox and seat modification Conclusion • New Gear box requires major tool changes • Adds expense • New motors requires less tool changes • Less expensive • Overall more efficient