The bearing press-fit holes are centered on a seam between the lower section of the mounting block and the upper “clamp,” which is secured via 4 ¼-20 SHCS bolts. This allows for easy swapping of the bearings, simplifying the already-complicated process of press-fitting the required components onto the shaft.

The motor mounting block is a static block which contains 4 mounting holes for M4 screws which affix the motor to the block.

This is a three-sided box with walls transverse to the axis of the shaft. This is designed to prevent shrapnel from a catastrophic failure from injuring nearby personnel without impeding the free flow of air to the PCB.

This is a three-sided polycarbonate box with walls transverse to the axis of the shaft. This is designed to prevent shrapnel from a catastrophic failure from injuring nearby personnel without impeding the free flow of air to the PCB

The PCB stators used for this project are not characterized for EM performance; instead, their primary role is to simulate the heat generated during normal operation. This is achieved by passing a DC through the stator windings from an external source, leveraging the high resistance of the traces to produce heat. Production PCBs will typically have trace weights of 4-6 oz to accommodate higher current densities. However, to minimize the required current for heat generation, the PCBs procured for this project feature reduced trace weights of just 1 oz. The PCB design employed in this project consists of two layers. This choice was primarily driven by the need to balance thermal performance with manufacturing complexity and cost-effectiveness. While a higher layer count could potentially offer enhanced thermal management capabilities, it would introduce additional manufacturing challenges and expenses.

The rotors are designed to enhance airflow and improve cooling for the PCB stator by incorporating features such as holes and fan blades that increase air circulation. Made from 6061 aluminum for its strength, lightweight properties, and high-temperature resistance, each rotor has a diameter of approximately 6 inches with an 8mm center hole for mounting.

One version (Figure on the top) was machined in the UCSD Machine Shop using CNC milling. The second modified version (Figure on the bottom) was ordered through PCBWay.