Fixing broken wiring on a Bafang motor?

[AndyOfTheSouth]

Thanks to Flecc, Frank and Nick for your advice by pm on this.

We managed to remove the outer cover and loosen the flange of the spindle. This gave access to the eight wires where they come out of the base of the spindle. However, we couldn’t slide the spindle up the cable because the cable was stuck (by silicone?) into the spindle.

The internal wiring was intact. The damage is all outside at the point of entry to the spindle where the rotation within the drop sheared some of the wires. Ideally, this is where the problem should be corrected, but there is not enough room at the entry to the spindle, so presumably the problem must be rectified further down.

I assume the next steps would be as follows.

Cut each of the eight wires below the spindle. This means that the spindle and cable is now free. The cable can now be pulled out of the spindle - forcefully if necessary, if the damaged wires will allow this.

Cut off the damaged portion of the cable and remove a suitable length of the outer insulation, then expose the tips of the individual wires.

Thread the cable back through the spindle.

Three of wires disappear into the motor, so these must just be joined to the incoming wires.

For the other five, either join these wires in the same way, or solder them afresh to the small circuit board.

Then reassemble and zoom off.

Any observations on this would be most appreciated – I won’t be offended by gasps of amazement at my naivety.

Thanks as ever

Andy

 

[flecc]

Yes, you're on the right lines Andy. The silicone rubber holding the cable into the spindle usually isn't very secure so it should pull out OK, but if not, just drill it out after cutting the wires at the other end.

The three thicker wires that disappear into the motor are the three phase current wires so you need similar thickness replacement wire, but the five thin Hall sensor wires can be as thin as you like. Obviously reseal the new cable into the spindle with silicone rubber once it's all repaired.

As long as you make sure all the connections remain the same, preferably by colour coding the wires, you should have no problems. That particular motor looks a lot easier to rewire than the ones I'm used to, having a neater internal layout.
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