Hub Motor Brushless Geared Hall Troubleshooting

[zukster]

I have a Bafang rear hub motor and it was working great. Then I redid
the controller wiring, and now it won't turn. So much for my upgrade

I scanned the form for a thread on motor
testing but didn't see anything. Is there a thread I missed that someone can point me
to? Otherwise I'll start one here. I'm sure all the wiring is color matched properly.
The controller is getting the proper battery power. Throttle connector is getting
5V and most of the Hall wires are getting 5V. One was 4.7V. Are you supposed to
test the hall wire voltages when everything is hooked up? I just measured what
was coming out of the controller. I have a current meter also, but if there is a
problem with the hall wires, will the motor still be getting power? I'd like to test
that the motor is okay. I tried two known good controllers, but I'd don't have a
second motor to test with.

 

[voicecoils]

OK, a couple things:

You need to test the hall sensors by measuring between the negative (black) and each of the three colours (yellow, green, blue) AND while measure this you need to spin your wheel backwards (forward won't spin the motor in the hub since it freewheels). This is done with the controller on and connected to the motor. You should see the voltage vary as you spin the wheel backwards for each sensor as it latches and disengages. If your reading goes from 5v to near zero and back again as you spin the motor backwards, it should be fine. If it's stuck low or high then that hall sensor has a problem.

Other things to check (without the controller being on) are that your connections are all OK. With your multimeter on the Ohm reading you can check for continuity on each of the five wires and also check that no 2 wires are shorted against each other somewhere.

I just had a hall sensor go bad on my bafang and I've just replaced it (for the second time).

You may also want to check to see if the hall sensors are still physically sitting in their slots on the motor. I had one come unstuck. If they don't sit exactly in the right place, they won't work. You can read about my first hall issue here: http://endless-sphere.com/forums/viewtopic.php?f=2&t=8605

 

[Joey]

I built a simple hall sensor tester using a schematic posted by fechter. I used it to diagnose my BMC hub motor after re-wiring the halls. It connects directly to motor standalone, that is, disconnected from controller.

viewtopic.php?f=2&t=5748&p=86223&hilit=+hall+tester#p86223

Joey

 

[yoyoman]

Are hall sensors easy/cheap to replace assuming I have the necessary soldering skills?

 

[zukster]

You need to test the hall sensors by measuring between the negative (black) and each of the three colours (yellow, green, blue) AND while measure this you need to spin your wheel backwards (forward won't spin the motor in the hub since it freewheels).

So I need to probe the wires when the motor phase/power wires and the hall to motor wires are all attached,
then spin the wheel. I missed that part but it makes sense.

And to test that the wires are okay(continuity), I need to poke into the wires close to the motor and
close to the controller and make sure there is little or no resistance (ohms)?

And to make sure there are no shorts, I would poke one wire close to the motor, then a different one
close to the controller (that its not supposed to be connected to) and make sure there is no reading
on the meter, because they are not supposed to be connected. (I'm adding a few extra details in case
someone who knows less than me reads this later)

 

[zukster]

I built a simple hall sensor tester using a schematic posted by fechter. I used it to diagnose my BMC hub motor after re-wiring the halls. It connects directly to motor standalone, that is, disconnected from controller. viewtopic.php?f=2&t=5748&p=86223&hilit=+hall+tester#p86223 Joey

Thanks Joey. I made your link clickable, here:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=5748&p=86223&hilit=+hall+tester#p86223

 

[voicecoils]

Yes, that's the idea. But as I mentioned in my first post, to test the latching of the hall sensor the controller must be on and you view the voltage on the multimeter as you spin the wheel backwards for each of the three sensors. They share a the positive (red) and negative (black) wires then each have a third coloured wire.

 

[johnrobholmes]

There is not a standard for the bafang motor wiring. Do not assume that the (insert color) sensor wire corresponds with the same color power wire.

 

[zukster]

I bought another Bafang SWXH 26 inch 36V from Keywin so I could keep testing. Here's more info.

The 3 Bafang SWXH's Keywin sent me had pretty easy wiring. You just switch the blue and
yellow on both the motor phase and hall wiring. Keywin emailed me these instructions:

Motor Phase: Green to Green. Blue to Yellow. Yellow to Blue.
Hall: Black to Black. Red to Red. Green to Green. Blue to Yellow. Yellow to Blue.

johnrobholmes on the other hand had three SWXH's in one batch, all with different wiring.

So if you're not sure with one you may get, I'd have to refer you to Knuckles handy procedure
with templates to print out to test all the possible combos:

http://endless-sphere.com/forums/viewtopic.php?f=16&t=3484&start=0#p81888

My controller is the little 36V 350W Infineon from Keywin, Ecrazyman@gmail.com for Ebay.

http://cgi.ebay.com/36V-350W-brushl...11332QQcmdZViewItemQQ_trksidZp1742.m153.l1262

I had the new motor setup on the vice in no time and drawing about 1.6 amps on the big red
wire with throttle full - as expected (as per Knuckles - 2.0 amps turning wheel - no load)

I'm lucky enough to have a current meter that you can clamp around a live wire to test the amps.
I have an old Universal Enterprises DCP 9 meter, but it still works fine. Setting is OHM for this.

Next I tested the Hall wires on the good motor with everything hooked up. Set the meter
to DCV. DC Volts. Black COM on the meter to black hall (while hooked up) you poke your
test prong into the back of the 6 pin block where the black pin plugs in. Now poke the
red test prong into the back of one of yellow, blue, green.

Now with everything powered on and hand rotating the motor backwards to its arrow. You
will feel the motor giving some resistance. It freewheels the other way. The hall sensors
read either 5V or 0V when you stop the motor in different positions. Note: You don't
need to turn on the throttle to test this.

So now I hooked up the flaky motor to the known good battery source, controller, and throttle.

All the hall sensors read 5V in any motor position, so something is probably
shorted inside the motor.

So should I take the new motor and wheel down to the bike shop to get the new one
laced in. They only charge $25. Or should I attempt to either return the motor or
open it up to see if I can fix it?

 

[johnrobholmes]

I bought another Bafang SWXH 26 inch 36V from keywin so I could keep testing. Here's more info.

The Bafang SWXH the Keywin is curently shipping has pretty easy wiring. You just switch the blue and
yellow on both the motor phase and hall wiring.

I just cracked open three and they all had different wiring. SWXH all of them, from the same lot shipped to me. One had sensor and wires matching in one order, the next two were not matching and in different orders on the stator. On the first I built and ran I swapped the green and yellow for normal running.

 

[zukster]

I just cracked open three and they all had different wiring. SWXH all of them, from the same lot shipped to me. One had sensor and wires matching in one order, the next two were not matching and in different orders on the stator. On the first I built and ran I swapped the green and yellow for normal running.

Wow. I bought 3 from Keywin and they were all the same. I'll edit my post to reflect this info.

 

[voicecoils]

If you have multiple bafangs, just swap motor cores and cases. Use your one bafang that's laced into a wheel, unscrew the side cover and pull the whole motor out. Then swap in the same from one of your other 2.

With the motor out of the hub casing, you can diagnose the short and fix up your wiring. That bafang should be good to go then!

 

[johnrobholmes]

It may be that different factory workers have different standards. I will inspect the motors to see what the real order needs to be, without respect to colors.

 

[zukster]

If you have multiple bafangs, just swap motor cores and cases. Use your one bafang that's laced into a wheel, unscrew the side cover and pull the whole motor out. Then swap in the same from one of your other 2.

With the motor out of the hub casing, you can diagnose the short and fix up your wiring. That bafang should be good to go then!

Is this pretty easy to do? I've never opened one up before. I'll need to figure out how to take the gear cog set of too.

 

[johnrobholmes]

Yes, it is very easy. Basically the whole unit slides out as one piece. There is not even a circlip to remove.

 

[voicecoils]

Yep very easy.

First, unscrew the nuts and washers off the axle that does not have the wires coming out of it and put them aside.

Then, undo the 6 screws on the sidecover and put them aside.

Lastly, pull on the axle on the side with the wires coming out (or push from the opposite side, doesn't matter). The motor core, freewheel, 3 planetary gears, sidecover, and axle all come out as one unit. What you're left with is a hub case still laced into the rim, open on one side. Looks like this:

Things to keep in mind: If you separate the planetary gear freewheel unit from the motor, don't lose the key! It locks the freewheel to the axle and sits loose on a keyway in both parts. If it comes out easily, then put it safely aside.

Also, the sidecover will separate from the motor, just pull on it and slide it off along the axle. You can do this if you want to inspect the motor windings, phase and hall wiring, or hall sensors.

Good luck!

 

[zukster]

I started a new thread here on how to open up the Bafang SWXH motor.
Its not quite the same as the one above:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=9969