Problems with Mac motor cutting out.

[Justin.Clements]

Hi folks,

I'm having difficulty diagnosing a problem with my MAC motor kit so I'm hoping someone here will have the knowledge and experience to tell me exactly what the problem is.

The problem started yesterday when I came to use the bike for my commute home from work. It had been absolutely fine on the ride in.

When I turn the throttle I get a short burst of power and then the motor stops. If I release the throttle and turn it again I get the same a short 1 or 2 second burst then nothing.

I've connected to a different battery and a different controller so I'm assuming the problem must be with the actual motor or hall wires. Does anyone have any ideas?

Thanks,

Justin

 

[Deleted member 4366]

Probably a hall sensor problem. Did it get water in it? You can test it with a Ebike tester:

http://pages.ebay.com/link/?nav=item.view&id=181246430524&alt=web

 

[Justin.Clements]

Hi d8veh,

I don't think any water would have got into the actual motor. I replaced the cover on the motor recently as the bearing had gone and it looked pretty clean and dry in there despite virtually everyday use over the last 2 years rain or shine.

Also it was dry yesterday until the eve. When I had the motor out a few weeks ago I did put some more grease around the gears. Could this have got onto the hall sensors to cause the problem?

Some of the wires are bear where they thread into the shaft although they were like that when I first bought the kit and don't seem to effect its operation. I did cover them with a bit of insulation tape recently and I've just taken that off as I found moisture underneath it. But I've just dried the area with a hair dryer and that's not cured the problem.

I have got one of those testers and I've just tried using it. I'm not sure how the steer crocodile clips are connected or what that means even!! So I left those disconnected.

I'm not sure how to interpret what the lights mean. The motor doesn't run at all when the tester is connected. The green power light is lit and the red steer light is lit. When I turn the wheel backwards the hall signal a(yellow) and c(blue) alternate although are both on in between. The b(green) does not light up at all so I assume that is the problem. The coil lights don't come on at all and the circle of red lights come on in 2's in rotation when I turn the throttle. The central 5v light flashes though this seemed to go off when I jiggle the connector for the handlebar on/off switch, so possibly a loose connection there.

Any help is greatly appreciated!!

 

[Deleted member 4366]

You connect only the 5 hall wires to the connector on the tester, then switch on the tester. When you rotate the motor backwards, you should see the three LEDs on the tester flashing in sequence. If one doesn't flash, that's your problem.

Then, you have to find out why. Barecwires running through the axle is definitely not good. Surely, you don't mean that!

 

[Justin.Clements]

Thanks d8veh. I guess it's the green sensor wire or the actual sensor then.

There is a tiny nick to the green wire where it enters the axle. The worst is the green phase wire though which is very bare. I've tried separating them out a bit to see what's going on. I cant see any bare wire actually touching the axle though. I'll upload a pic so you can see what I mean.

Could a short have killed the sensor? It seems odd that the motor runs for a few seconds each time.

 

[Deleted member 4366]

Oh dear! You'll have to repair that or you'll be looking for a controller too. It's a problem to get the eight or nine core motor wire though unless you have a scrap motor to cut it off. If you have enough length, you can pull it through to lose just the bit between the damage and where they're presently soldered.

 

[Justin.Clements]

Thanks d8veh. I haven't really got any spare length but maybe I could move the controller forward a bit.

Would a short destroy the controller? I have a spare controller that I replaced a mosfet in last year. I've already tried connecting that up and get the same result.

Whilst you are clearly saying the chaffed wires need sorting out as I can't see any wires actually touching each other or shorting on the shaft (it's easier to see that looking at it than in the photo!) I'm assuming the problem will still be with the hall sensor.

 

[Justin.Clements]

Are there any continuity testing I should do to check for a short?

 

[mechaniker]

I would change the motor-cable if you have some welding eperience you can handle it. I always use extension cord, cut the side with no need away and fix the cable to the motor. It´s no so difficult but need time and patience

I didnt wrote a manual for the mac-motor how to do, I only wrote one for the CST-bafang. Main steps are the same open motor disamble motor old cable out new cable in. To put the cable trough the axle I use soapwater

I wrote a manual how to measure controller and Motor incl. Hallsensor but I still had no time to translate it in english but I guess by google translate it is easy to understand
have a look here: http://fatbike-motor.com/download.htm

Then you would have erased one obvious failure

regards
frank

 

[Justin.Clements]

Thanks Frank,

I did also wonder whether it wouldn't be better to use 2.5mm or 3mm flexible cable than the thick strand cable currently used.

 

[mechaniker]

hi justin,

it would be better but brings the price 2usd higher and the china factory only focus on the price never on quality I had this discussion for many years and tried to explain they should make the price higher for a better quality......

 

[Justin.Clements]

Oh dear! You'll have to repair that or you'll be looking for a controller too. It's a problem to get the eight or nine core motor wire though unless you have a scrap motor to cut it off. If you have enough length, you can pull it through to lose just the bit between the damage and where they're presently soldered.

Hi d8veh,
Thanks for your help so far.
I've been trying to pull the wires through as you suggested. I've squirted a bit of wd40 in where the wires enter the shaft and am using some thin nose pliers at the stator end to pull them through. But all I seem to be doing is stripping the wires.
It feels like the angle that the wires come out of the shaft is just too acute to pull the wires through in this direction. Have you succeeded in doing this before and do you have any tips?

Thanks,

Justin

 

[Deleted member 4366]

You have to push from one end and pull from the other. Once you're round the corner, it's easier. Good luck!

 

[Justin.Clements]

Hi wonder if anyone can help with this.

Following the above I ended up making a new cable. I also replaced all 3 hall sensors and the pcb they're attached to (thanks Fordulike for sending those with the other MAC parts).

The lights on the tester now all come on and off in turn when the wheel is turned. There is an overlap when the next light comes on before the previous one goes out. I assume that's normal.

But when I run the motor I get the same (or at least very similar) problem. The motor cuts out after a short period. Although this is longer than it was when the problem first started probably more like 4/5 secs now instead of 2/3. Again dropping the throttle and turning again puts power to the motor immediately.

I know the problem is not the controller or battery connection as I've been using my girlfriends wheel and motor on my set up while trying to fix mine.

I feel it's got to be hall sensor position but I've glued the new hall sensors in exactly the same places as the old ones and there really aren't any other options.

So has anybody got any suggestions or ideas of what could be causing this?

Btw if anyone reads this who plans to make up a new phase/hall sensor cable, I used some 6 core burglar alarm cable which had all the right colours for the hall sensors and used 3mm thin wall automotive cable for the phase wires and some heat shrink cable sleeve to pull them all together.

Thanks again,

Justin

 

[Deleted member 4366]

I'm not sure, but I think the middle one might have to be the other way up. Is there anywhere that mentions the orientation?

 

[Justin.Clements]

Hi again d8veh,

I saw posts about orientation on endless sphere but it wasn't the mac motor so I don't know. Looking down at the pcb all the positive feeds (red wire) go to the left terminal negative (black wire) in the middle and output (coloured wires) on the right, so I put them all in with the beveled edge facing out.

 

[Fordulike]

Hi again d8veh,

I saw posts about orientation on endless sphere but it wasn't the mac motor so I don't know. Looking down at the pcb all the positive feeds (red wire) go to the left terminal negative (black wire) in the middle and output (coloured wires) on the right, so I put them all in with the beveled edge facing out.

IIRC, the hall sensors can only be slotted into place one way round, due to the bevelled edge, so I don't think wrong orientation will be a problem.

 

[Justin.Clements]

Before going to bed last night I tried running the motor again and it didn't cut out. I hate intermittent problems!!!!

I will road test today and am hoping that I'd just not made a good enough connection with the controller when I first plugged it in which improved after retesting the sensors.

Come to think of it the japanese connector does feel loose when I plug it in.

So now I'm worrying, could a loose connection from controller to hall sensor cause the hall sensor to fail and be the original cause rather than a short from the frayed cable?

 

[Justin.Clements]

Oh dear, bad bad bad.

I test rode it and found that at about half throttle I got a juddering from the motor which then disappeared at full throttle/speed. The motor seemed to run at the same power level as before but sounds different somehow (i think lower pitched and slightly louder).

I assume this must be a hall sensor issue although on the tester all sensors are lighting up in turn.

I then went up a hill and I assume the part they call the clutch started slipping. It felt just like a car clutch slipping.

I had to take the shaft out to feed in the phase wires and wonder if I've damaged this part somehow, it did require a lot of levering to free it. I also put lots more grease on the gears so maybe they're slipping somehow(?).

I have a week off to do jobs and must get on with other things but ideally need to get this sorted by Sun eve.

Any ideas what I should do next?

 

[Deleted member 4366]

What feels like slipping clutch could be just the controller losing sync unless you heard the motor whining at full speed with no drive.