SWXH motor wont work- Help needed!

I have a SWXH type 8fun rear hub motor that I cannot get to work correctly. When I hook it up to the battery and start to pedal the motor starts to skip (or rather try to skip) in the wrong direction. Using the throttle does nothing and the skipping is in an even pulse. It is not possible to turn the motor by hand in the wrong direction (neither with nor without the battery connected). I thinking it might be something mechanical preventing the motor to spin, but even if it did it would be in the wrong direction.

I have measured the voltage from the hall sensors and they seem ok. The batttery is fully charged.

Any ideas?

It's hard to be sure from the description, but it sounds like the motor is running backwards and is a geared hub, so that the freewheel is just letting the motor spin inside it's casing, not spinning the wheel.

If this is the case it is likely that the phase / hall wires are not in the correct combination (connecting color to color doesn't always, or even usually, work). If so, first see if your controller has a "self-learn" function. If not, you can use the thread and/or wiki article How To Determine The Wiring For A Brushless Motor And Controller to get it going in the correct direction.


It could be something else, based on your note that " It is not possible to turn the motor by hand in the wrong direction ", which could mean that it's locked up or it could mean that it's freewheeling in the backwards direction, when it should be freewheeling in the forwards direction. If that's teh case it could be installed backwards, or the clutch inside it could be installed backwards.

Thank you! Yes, some phase problem might be it. Thing is the bike is used (found it in a dumpster) so I'm thinking the way the phases were connected should be the correct one. But its worth a shot. I don't think my controller ha a self learn function. Its a generic chinese box and I have sorted out what all cables do exept three (a single yellow, a single black and a double black/blue). None of them are for brakes.

Since it doesnt turn backword I thinking it might be a clutch problem as well.

The way your first post said it made it sound like you'd gotten a new motor and were still trying to set it up. The advice given applies only to that kind of situation.


If it was in a dumpster, then it was probably tossed out for the problem, and different advice applies. In this case, it probably has broken gears inside, and bits of broken teeth are preventing gears from meshing correctly. You can open up the motor to verify. There are threads on ES about these motors that should help, and may also list sources for new gears.



It's best to give *complete* details of a situation to get the proper advice.

Thanks again. Yes I'm leaning towards the broken gears theory. Will open it up to verify.

In regards to your comment about *complete* details, it can be somewhat difficult to know what constitutes *complete* regarding an area where you lack expertise. But with a few questions back and forth in a forum, more knowledgeable members such as yourself can help investigate the problem and the necessary details will eventually be given. A method that has worked since the days of Socrates

True; however my comment was because here on ES we get a lot of posters that we have to drag the details out of, and even then we don't always get enough to help them, and they get mad when we can't tell them what's wrong, or that we are asking them to test too many things (because they won't give us the details that would narrow down things).

Sometimes eventually they post that they fixed it themselves and what the symptoms were that led them to replace that part, but none of that was in the original post, even though questions were asked originally that if answered with that info would have let us help them find that immediately, instead of after days or weeks of poking and prodding at it.

You might see how it could be a bit frustrating when details that change the nature of the problem aren't posted to start with.

You need to determine whether the problem is in the motor or the controller. Disconnect the motor from the controller. If you can then turn it backwards easily, you have either melted phase wires in the controller or blown mosfets. If you still can't turn it backwards, your only option is to open it up to see what's wrong. It could also be the wires damaged where they go into the axle. If they are damaged, the motor needs to go back in the dumpster.

I managed to open the motor (with a chisel and some violence - didn't have the right tool). I started out looking att the planet gears and the clutch cause I suspected the problem would be found there. But they seemed to be in order. And the motor itself was spinning as it should. Nothing stuck. So I hooked it up without the casing lid on and lo and behold it started spinning exactly like it should.

Turns out the problem was a completly stuck ball bearing on the driveside - the one inte the casing lid. Problem solved.