In 2021, the electrical box (ebox) was completely overhauled to address a number of issues with the previous design.
KEY PROJECT CONTRIBUTORS
| Mechanical Team | Electrical Team |
|---|---|
| @Tibi (please add proper link) |
Progress To Date: E-Box Progress Tracker (2020-2021)
TL;DR
The new e-box is comprised of a thin 0.06" single piece weldment to maintain a light weight while providing a stable site for connector mounting on the front panel. The front panel has mounting spots for multiple PP15 connectors, a pair of PP75 connectors, two USB connectors, two ethernet connectors and two general purpose cable tie racks for strain reliefs. The frame will also include punched in PEM fasteners to reduce required hardware, and will be powder coated to provide electrical insulation. It features a clear acrylic lid with a nice handle, quick-lock latch mechanism and detachable hinges to allow the easy access to the interior of the ebox. Four high CFM fans are placed on the left and right of the ebox (two intake and two exhaust) to prevent the Jetson from overheating and throttling in Utah. These fans feature fine grain filters on the intake and course grain filters on the exhaust to prevent dust from entering the ebox. The ebox will also have interior hardware to allow for a second level comprised of a 1/8" thick acrylic sheet on elevated standoffs. The exact shape of this second level is still to be determined.
ISSUES WITH PREVIOUS DESIGN
The 2020 ebox was constructed using corrugated plastic sheets and aluminum angle. This design was very light weight, but was faced with the issues described below:
- Outer walls would easily bow with any applied force.
- Front panel was one large rectangular cutout (circled in red) that offered no stability for connector mount points or cable strain relief, so you could easily accidently yank and damage a wire.
- Lid was fastened to the top of the box using four thumb screws (circled in blue), so it was pretty inconvenient to open the box and make adjustments as you had constantly screw and unscrew the lid.
- Second level was added to this ebox hastily using a piece of plywood, rather than having a properly dedicated second level.
- Ebox was not insulated from the rest of the frame; during wiring for 2021 SAR video submission there was an incident where a live wire in the ebox touched one of the metal brackets. This charged the bracket, and led to one of the electronic components shorting and breaking.
2021 DESIGN FEATURES
Outer Frame
For the 2021 ebox, we wanted to make sure that the box frame was very strong and stable, while maintaining a light weight. We designed a single piece weldment from 0.06" thick 5052 aluminum (using material and thickness recommendations from our fabrication sponsor, demtool). This piece will be laser cut, folded and welded on all edges, so the frame should be very stable. Various cutouts are included on different parts of the ebox to allow for the mounting of a number of different components. The frame was designed using guidelines provided by our machining sponsor, and careful attention was directed towards ensuring that interior bend radius was equal to material thickness, minimum distance between cutouts and bend lines were met and small gaps were present at folded edges.
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