Anth's Computer Cave

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.



A brushless DC motor. Picture: Anthony Hartup

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.

A brushless DC motor. Picture: Anthony Hartup

Of course I would not miss an opportunity like this, so let's tear it down!

A brushless DC motor. Picture: Anthony Hartup

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.

A brushless DC motor. Picture: Anthony Hartup

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.

A brushless DC motor. Picture: Anthony Hartup

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.

A brushless DC motor. Picture: Anthony Hartup

You can see from the images that the coating around the rotor was substantially damaged.

A brushless DC motor. Picture: Anthony Hartup

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.

A brushless DC motor. Picture: Anthony Hartup

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.

The spoils

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.

A brushless DC motor. Picture: Anthony Hartup

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!

Cheers

Anth


Previous: CP1515 laser printer teardown

Next: Teardown: Rear-projection TV

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