Brushless DC Motor Teardown
Today we are tearing down a high-quality brushless DC motor to see what we can scrounge to reuse for our projects.
The victim is a Tork brushless motor from hpi-racing. I am told it costs up to $200 and reached incredible speeds in an RC car. Unfortunately it has seized so a friend dropped it round thinking I may want to strip it.
Of course I would not miss an opportunity like this, so let's tear it down!
This is a really robust motor. It weighs 420 grams, nearly half a kilo, and the casing is about 3mm thick with the flutes adding further weight. It has three heavily-insulated cables, two for power and one for signals.
The base came away easily once I removed three allen keys. The bearing inside the base spun freely so that was not causing the problem. Inside the casing a thick coil of copper surounds the rotor. There was some dust inside the unit.
Another three allen keys removed the top from the motor. That bearing also spun freely. The rotor was still tight in the casing.
With a bit of pushing and pulling the rotor began to loosen and eventually I managed to work it free from the motor.
You can see from the images that the coating around the rotor was substantially damaged.
The inside of the casing seems undamaged other than a few strands of wayward copper, but I don't really know what it is supposed to look like.
I can't help thinking that a top-end motor like this would be highly repairable. The ideal recycling outcome from this excercise would be to get this motor running again.
I have been on the hpi-racing website and they have replacement high-torque rotors for some of their other motors but I can't find one for this motor. I will search further when I have the chance. If I can't fix it, there are some handy bits to reuse.
From this teardown we have gained a sturdy metal casing with a bearing at each end. We also have a strong shaft to match those bearings and the brass bushes to hold it in place laterally in the casing. This unit is a ready-made gearbox or hub. With the copper coil removed it should weigh less so I think I can use it as the base of a rotating sensor mast for one of the robots.
Although not on the same scale as some previous teardowns, this one has been really useful. If I can repair the motor I will have the perfect motor for the cutting head on a CNC router I plan to make soon. If I can't repair it I get a fantastic contraption to utilize as a gearbox and hub.
I'll be happy either way!
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