Troubleshoot Mac Motor

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Apr 1, 2018
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15
I have a mac motor that I bought years ago from Paul at EM3EV. Like many people I've put thousands of trouble-free miles on it. Right up to last week.

I hit a curb, that I've hit hundreds of times before (without problem), and the motor stopped working.

I have a CA which showing the PAS speed sensor working normally, but the wheel doesn't provide power at all. If I stop pedaling, then start again, it WILL begin to apply power for 1 - 2 seconds, but then it stops again.

I checked all the wire connections (thought it might be a broken wire), I took the motor off and apart to see if I could visually see anything ... but to my inexperienced eyes, I didn't see anything amiss.

Any ideas on what it might be? OR How I might go about diagnosing the problem?
 
Could be any wire connection, but it kind of sounds like a hall sensor/sensor wire. Grin has some nice troubleshooting info here: http://www.ebikes.ca/learn/troubleshooting.html
 
Yes, the easy Hall sensor test would be in order. It sounds like one of the Hall wires has septarated from the PCB.
 
Thanks molybdenum for the link. Tons of info.

And thanks to motomech ....

I'm picking up a multimeter today and should know by nightfall what I'm looking at.

Cheers
 
A day later ...

After testing, it was the yellow wire that indicated a problem. Following the testing on Grin, the multimeter doesn't change at all....it's stuck on 5.00.

So, I guess the next question is: where do I get the right hall sensor?

Thanks.
 
It's probably not bad, these large geared motors have a bad habit of the Hall wires pulling off the printed circuit board. It may just need resoldering. If you need a Hall, Grin sells them. Take the motor apart and see what you have.
 
I did that today (took it apart), but left my phone in the car ... and my wife's out all day.

I'll post a couple of pics later.

I didn't SEE anything broken or unsoldered, but sounds like you have more experience than me and know where to look.
 
trace the "dead" wire to the PBC and peel back the epoxy in that area. It's likely the wire will come off w/ the epoxy.
 
I'm mechanically inclined, but just haven't done a lot of research about this problem ... so I apologize if I ask any 'simple' questions.

When you say PBC, do you mean the green part?
 
yes, it's the green part "printed circuit board" where the hall wires lead; The board sits on top of the three hall sensors, which are probably OK. motomech was saying the hall wires sometimes come loose under all that epoxy where they attach to the board. softening the epoxy with a heat gun sometimes helps...
 
IMG_20180411_174618.jpg

I gave each wire a gentle tug, but they seem to be well attached.

Tomorrow, when the wife is out, I'll 'borrow' her hairdryer and pull the PCB off the motor; that might reveal something more.

Thanks y'all!
 
Be careful, the PCBs are soldered to the hall sensors, which are attached to the motor stator with more epoxy. You can use a multimeter to test for continuity on the offending hall wire between the PCB and the controller connector, ruling out a break in the wire before proceeding to try and remove the PCB. Also listen to what motomech says. He,s plenty of experience in these things.

Considering the problem arose when you hit a curb, I'm inclined to think something got jarred loose. There are a few threads with good pics showing the removal of the PCB and hall replacement on this forum. You will want to read these carefully before proceeding.

Like this one:

https://endless-sphere.com/forums/viewtopic.php?t=63771
 
Well, not that much experience, a pair of Ezee V1's. But those motors had a common prob., the wires were too short and when soldered in place, they were taunt, and one or more of the wires came off w/ the epoxy. Easy to see the prob. Yours look like they are still attached. When you the green thingy :) off, you might be able to put one lead of your multimeter on a leg of the suspect Hall. If there is continuity to it(other lead on the main wire connector), but it did not produce a pulse, then it must be the Hall itself.
For my repair, due to the very small holes where the sensor goes and the difficulty getting everything perfectly clean of old epoxy, it was easier for me to start over with a new PBC and Halls. The new PBC from Grin is a V2 version w/ much bigger holes which is much easier to work with. I think the new PBC and the 3 Halls were around $30, not too bad, so you might consider that approach if you have any prob.s repairing the old parts.
 
If you look closely at the PCB where the center (blue wire) hall is connected, the left of three solder points is missing (which leads via the PCB trace to the red wire). Each hall sensor has three wires soldered to the PCB. Red is for +5V and will connect via the PCB to all three halls, black is for ground and similarly connects to all three halls via the PCB. Blue is the sensor wire for the center hall, and only the center hall.

I'm wondering if the left leg of the center hall has come loose from beneath the PCB and broken free of its solder, resulting in loss of power to the blue hall?

mac.jpg

I borrowed this image from another thread (Posted by SkyknightJohn, https://endless-sphere.com/forums/viewtopic.php?t=63771) to illustrate how the three pins of each hall are connected to the PCB:
Hall PCB.jpg
 
grumpygaijin said:
After testing, it was the yellow wire that indicated a problem. Following the testing on Grin, the multimeter doesn't change at all....it's stuck on 5.00.

The kind of thing you are looking for isn't always obvious - a cracked solder joint can look just fine. Without knowing by your report that the yellow hall was the culprit, I would suspect the connection to the blue hall shown here - although the image is tiny and unclear.


suspectMacSolderConnection.jpg


Although it's a fair chance it is a hall issue, it might also be a broken cable run (the +5V you saw on the yellow hall pin was coming from the pullup resistor in the controller, not the cable and hall so there's no evidence that the cable is good). I would check the continuity of the yellow wire right up to the hall solder pad while flexing/pulling/pushing the cable where it enters the axle - a beeping kind of continuity tester is best for this. This is a high stress point prone to breaking. Next I would reflow the PCB connections and retest the hall(s) with the PCB in situ. To get the hall pullup resistors in play you will need to plug in the controller hall connector and power it up even though the motor is disassembled - unless you use an external pullup, etc. Leave the phase wires disconnected.

Only after exhausting the simpler mechanical issues would I pursue hall replacement.

EDIT - okay - some cross-posting with molybdenum. Same observation though regarding the blue hall....
 
mm2.jpeg

I took a closer look at it; turns out it was just a bad photo....as I think this one shows.

Thanks y'all for the help. This is a great board. I appreciate everyone's help so far.

I'll get to tearing it apart over the weekend. I took a look at it today and decided I needed more time to tear it down than I had. No point in getting part way into it then having to stop.
 
Yes, try measuring the continuity of the yellow wire from the motor end to the controller end to make sure it's not broken somewhere between. Common fail points are right at the controller connector and where the cable comes out of the axle.

I've found if you heat up the epoxy stuff to 100C, it becomes sort of rubbery and can be dug out with a small screwdriver. Don't overheat it though.
 
If your multimeter doesn't have a dedicated continuity function, you can test continuity by turning the dial to the lowest setting in the resistance mode (ohms Ω). You should get a reading of 0 (no resistance) if the wire is good. It will read 1 or "OL" if the wire is broken.
 
On my way to work today I took my multimeter, tested continuity and all is good, so ... it looks like I'll be pulling it apart tomorrow or next.

Cheers everyone that's helped.
 
Well, things didn't work out as I had hoped. Pretty sure all I've got left to hang on the wall of shame is a trophy of what NOT to do.

I thought I'd combine parts of the Grin and spinningmagnets guides. Everyone, don't be like me. Spinningmagnets is the only way (certainly for my motor).
IMG_20180416_154602.jpeg

I've got the puller set up and ready to go.

[I like spinningmagnets idea of using coins to space it out, but found that the end of the hook grabs the edge of the magnet hub pretty well.]
 
That didn't work and I end up with this:
IMG_20180416_154546.jpeg

While applying moderate pressure, there was also some awful cracking sounds and the shaft got woobly loose in the bearing.
 
At that point I figured there was no reason to be gentle with it, so I hacked off the wires

IMG_20180416_160656.jpeg

started disassembly of the wires and all that. A little knowledge can go a long way. Because

IMG_20180416_164511.jpeg

I found what I had overlooked in my eagerness for the quick fix ... the all important circlip.
 
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