The bench test of the motor from the previous post, as the title may imply, went quite successfully.
Instagram can’t embed (☹️), but here was our initial reaction.
https://www.instagram.com/drexelelectricracing/p/DG4TR4muHuM/
This may not be a big deal to the more established teams, but for us, it was the first time we have ever spun a motor under its own power, and with our own accumulator. We had to make lots of changes to previous designs to accomplish this, including making an entirely new high voltage box to fix critical issues that the previous iteration had (and, as a bonus, it is smaller!)
Now for the bad news, we discovered a lot of EMI issues in our low-voltage system while running the motor. We still have the goal of running the car under its own power during this term, but we might be pushed back by a few weeks while we diagnose the EMI issues among other small fixes as parts come in. Regardless, we will still push forward and get our very first car to move, albeit slowly, under its own power.
“DER 2”
While our Electrical sub-team has been working hard on debugging the high and low-voltage systems, mechanical has been slowly picking away at major systems for our second car, DER2. Our first car is plagued with many mechanical-related issues stemming from legacy decisions, and we believe it is in the best interest of safety to not test DER1 at high speed in its current form.
Currently, we have a senior design team working on our DER2 accumulator, and depending on the pace that DER2’s design develops, we may adapt this accumulator to the old car to get some rudimentary testing data and practice proper data acquisition. Otherwise, we believe that DER1’s accumulator design, despite mostly passing accumulator tech, is structurally unsafe to operate with any significant vibrations or forces being applied to it. DER2’s accumulator will be using much more suitable materials for the battery segments and will have a better packaging design to minimize potential fault areas.
Outside of the accumulator, we have began development of our new wheel assemblies (switching to 10″ CL wheels to match our IC team and save significant weight) and have been defining preliminary suspension points. Below you can see our recent progress on working out where items are going to be placed and mounted. Our goal is to have a first “full” draft of the car’s packaging by the end of this quarter, and then we can get started on chassis/do adjustments as needed. Body and Ergo members have also been hard at work redoing the carbon fiber for DER1 to get practice in anticipation of the DER2 chassis design. Some other non-tangible developments have been creating and documenting braking system calculations and design parameters and setting up a more efficient fileserver and part naming system (to match the cost report better).
That’s the cliff notes of what’s been going on at DER as of recent. Not sure if we will be making another post before our IC team’s competition, so if not, please go visit their website and support them going to competition this year! As always, we trudge forward through the uncharted territory of post-motor-spin, and we hope that our next post is another indicator of progress.
-Shane, Mechanical Lead 24/25