156B Week 5

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• Further analysis of the effects of the accumulator's internal air sack pressure where made with the following trends:

  • At an accumulator pressure of 431 kPa (62.5 psi), the water pressure at outlet, once the pump is on, is around 689 kPa (100 psi). This is close to the minimum recommended pressure to run the nozzles

  • At an accumulator pressure of 69 kPa (10 psi), the water pressure at outlet, once the pump is on, is around 469 kPa (68 psi). This is too low to run the misters

  • Pressures in between follow a similar trend, but more tests around 431 kPa may be needed

• The team has agreed to prototype a new design that uses two aluminum rods through the bottom of the tank that can be laterally adjusted by sliding one rod. 

  • The rods and the dashboard of the cart will be used to support the approximately 28 Kg system

  • The sides of the system will be covered by an acrylic plate with a clearance hole for the rods to fit into, and the lenght of rod at the bottom of the tank will be secured by aluminum brackets just large enough to allow sliding

  • Electrical components will be placed on an acrylic plate above the tank

  • Access holes for the tubes and wires will lead from the back of the tank up into an opening in the acrylic plate

  • A half cylinder dome will cover the electrical components and the misting fans will attach to reinforced sections of this dome, possible by means of acrylic above the electronics

Accomplishments from Previous Week

• A bike tire pressure gauge is now being used to measure the air pressure within the accumulator, which allows the team to adjust the exiting water pressure of the nozzles by a known amount

• 10,000 uF and 15,000 uF capacitors have arrived and are ready to be used along with the converters in the prototype design

• Acrylic and aluminum brackets have been cut and machined to fit the aluminum beams onto the container with tank and other electronics inside of it. 

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• Finish tank and electronic component container portion of prototype design (Team)

• Update Website (Oscar and Erasmo)

• Finish testing with newly arrived Capacitors

• Determine ideal accumulator pressure with recently acquired pressure gauge

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• The team should focus on designing the mount to attach directly onto the cart's upright sunroof supports and to not worry too much about windshields (sponsor meeting 4-27-17)

  • For the prototype being created, the team will adapt a method currently used by the bar mounted misting system with some modifications, such as implementing a small rod in the windshield access holes to limit the vertical motion of the mount instead of relying on friction

• EZ-GO is currently transitioning to using Lithium ion batteries instead of the lead acid ones. This may change how the mister system is powered

  •  More research on these batteries is needed, but preliminary research implies that these batteries are mostly easier to maintain with better duration and performance 

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• The implementation of the step-down current limiter may not be needed (Meeting 4-24-17)

  • The current limiter has been identified as an extra 'fail-safe' for the pump, and with the use of proper filtering following the converter it is not needed

• vibrations should be buffered with a medium such as rubber between the brackets and the pump (Meeting 4-24-17)

  • The Seaflow pump comes with a rubber base that may absorb some of the vibrations from it, and the base will be secured onto an acrylic plate instead of the aluminum brackets. The brackets themselves will attach to the roto-molded water tank

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• NA

Risks and Areas of Concern

• Standards for golf cart battery combinations are currently changing which makes the implementation of a converter essential

Resources or Information Required but not Available

• material properties for the sunroof support bars vary and general dimensions are difficult to find. The team may have to assume dimensions follow what we have at hand.

Schedule

• Our next milestone will be to assemble the final prototype and mount it onto the golf cart

Budget (list amount spent and amount remaining)

• Amount spent between 4/23 to 4/30: $115.37

• Amount remaining: $1538.47

Progress on Report and Webpage

• Applicable standards sections has been added