Determining the Wiring for a Brushless Motor

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Article in progress, edit as needed.

Links to garner info from: (need to copy thread into this article)

John in CR: "There are 6 valid combo's, 3 forward and 3 reverse. The only exceptions to that are a few BLDC motors that require a special controller, but those with some odd timing wouldn't run in reverse. The correct firing sequence for forward is for example A-B-C, which since it repeats is the same as B-C-A and C-A-B. ie all end up A-B-C-A-B-C-A-B-C-... just with a different starting point. You just have to match up the same hall order and sequence. Swap any 2 phases and you get reverse C-B-A, which since repeating is the same order as B-A-C-B-A... or A-C-B-A-C... "

Alan B: "The way I approached it is to analyze which wires were easy to change (the phase wiring is easy to switch on my setup) and which were hard (the hall sensors are small fragile difficult to swap pins). So I want to minimize the switching of the tiny hall wire pins.

Assuming the +5 and ground of the hall wires are correct that leaves the three hall signals to play with. Only two combinations of those three wires are necessary to explore. One corresponds to forward rotation and one to reverse. We don't know which direction corresponds to which wire configuration so we may have to try both. The two combinations differ by the switching of one pair of wires. For each directional hall setup we have to try all combinations of the phase wires of which there are six. If none of those runs forward smoothly at low current then we have to swap one pair of hall sensor wires and again try the six phase combos. Twelve to test. Done."


Also a Google doc created by NeilP. Trouble-shooting chart.jpg

Phase-Hall-Wire-Combinations Print version PDF: [[1]]


You should know which hall spacing your motor has. 60° and 120° are common, others would be possible but are uncommon. You can determine which one you have if you connect a hall tester for example