This Homemade Machine Winds Large BLDC Motors

Extremely popular BLDC motor models are relatively affordable. But if you need anything even slightly specialized, the price shoots up dramatically. Aotenjo found that it was more economical to rewind off-the-shelf motors (preferably used) for the task at hand and built a machine to do the winding. That worked well and now he wants to rewind wind even larger BLDC motors, so he upgraded the winding machine to handle some seriously big spinny boys.

Aotenjo’s general use case is rewinding high-speed, low-torque BLDC motors (like you’d get for a drone) to make them low-speed, high torque and suitable for servos in automated machines. That concept was successful with large drone motors, but now Aotenjo wants to move up to a different tier. He wants to rewind the kinds of BLDC motors made for e-scooters and those are pretty massive — literally.

Managing that mass was the focus of this new motor winding machine design. The main stator axis was scaled up to 25mm and the original lead screw was upgraded to a ball screw. Beefier mechanical parts were CNC-milled by JLCCNC.

To perform the winding motion, the machine requires four motors. The first moves the stator in and out relative to the winder, the second rotates the stator, the third spins the winder, and the fourth adjusts wire tension. All of those are BLDC motors operating under closed-loop control, overseen by Aotenjo’s own Aotenjo Master controller. That controller is built around an STM32 microcontroller and communicates with the motors’ onboard drivers through a CAN bus.

The upgraded motor winder is promising, but Aotenjo hasn’t yet finalized the design. He plans to test it with the larger BLDC motors, which can weigh as much as 4kg, and refine the design as necessary.