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Entry 3: RELEASE THE SMOKE

A project log for Reverse Engineering: Brushless DC Motor Controller

With a pile of BLDC controllers lying around, and none that do exactly what I want: better to re-use the parts than start over from scratch!

jorj-bauerJorj Bauer 12/28/2016 at 00:500 Comments

That durned magic smoke got out. It left behind some black soot and melted connector.

So how did that happen, you ask?

Well. From the last entry, it only took 6 more wires - PWM and commutator control lines - to test whether or not I could make the motor move. So, of course, I wired them up.

Then I realized that the PWMs weren't on PWM pins on the Teensy. "No matter," thinks me, sipping gently on a Jade cocktail (champagne, midori, curaco, lime juice, bitters). "I'll just run the PWMs at 100%, and we'll watch this run up to full speed." Warning bells go off, but I'm ignoring them. "It just won't run by itself." Sip. "I'll code it to move to the next phase from the previous, based on the sensors." Sip. "I'll pull the battery when I want to stop it from running full out." Sip.

Sip.

Solder.

Code.

Sip.

Upload.

Sip.

Connect.

"P1" it exclaims! The motor jumps.

"P44" and "P43" follow quickly after. The motor jumps again!

And then it stops.

Dead.

Just long enough for me to think about what it's doing, and for me to realize I should really give it a push. Right now. Quickly.

*Poof* goes the magic smoke, as the FET trying to power phase W gives up the ghost, having valiantly tried to move the damn motor in the wrong order. Rest well, FET; you'll always be remembered. Because I wrote this log entry about you.

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