Download Human Generated Power for B9 Better Water Maker

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
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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
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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