GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Thuktun on June 29, 2015, 02:25:57 PM
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I was riding to work this morning, about halfway here when I stopped at a red light. When I went to go again something seemed off right away, I realize now that was the throttle not doing anything at first, I started moving after a second but with a lot of noise and vibration.
Walked it to work from there, only just now had a chance to go out in the parking lot and investigate further.
The throttle does nothing from a dead stop. No response at all. If I pedal up to about 7km/hr it will cut in but with the aforementioned noise and vibration. It's light at first but the faster I go the harder it shakes and louder it buzzes. It also buzzes and shakes when the brakes are applied. No problem when freewheeling or pedaling. I thought maybe the brakes were causing it since they were the last thing I touched before it went wonky so I disconnected them and the cruise control, same problem.
So what's up? Another bad controller? How can just stopping at a red light mess this thing up?
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I rode it home because I didn't have much choice.
There are 3 wires from the controller to the motor, I assume this means it gets 3 pulses per revolution. I think what mine is doing is only pulsing once or twice per revolution. The rate of vibration is directly proportional to the speed of rotation and the strength of the vibration directly to the amount of work the motor is doing. If it only pulses on one side it would vibrate and hammer on one side, right?
Same question though, why, and how to fix?
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It sounds like you may have one of the following:
- a failed Hall Sensor
- a poor phase wire connection
- a poor Hall sensor connection
- a faulty controller
You will need to remove the controller to check that the three phase wires are still properly connected:
(http://www.arhservices.co.uk/GoldenMotor/Smart%20Pie/4_zps406bca35.JPG)
Also check that the 6 pin Hall sensor connector is properly fitted and that none of the crimped sockets have been dislodged from the connector housing during assembly:
(http://www.arhservices.co.uk/GoldenMotor/Hallsensorplug.JPG)
(NOTE: this is an MPIII connector shown here)
Make sure that the five crimped sockets on the hall sensor leads are fully inserted into the connector block as shown in the above picture, and then make sure the connector is clicked properly into the socket on the controller.
If nothing is visually obvious, you will need to check the operation of the Hall sensors using a voltmeter to check for pulses of 0~5V on each of the Hall sensor signal wires (Yellow, Green and Blue) as the motor/axle is slowly turned by hand.
If all the connections are good and the sensor voltage readings are also correct, I suspect that the controller itself may be causing the problem.
Incidentally, you should have around 120 pulses per revolution (not 3) as I seem to recall there are approximately forty magnets that will all switch each of the three Hall sensors every revolution.
Alan
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Looks like a hall sensor. All the connections are good. I'm reading 4.25v on the red wire and 3.22v on the blue and green depending where the wheel is. The yellow only shows 0.01v.
So where do I get suitable hall sensors and how do I replace them? If there is a more robust part then the one it comes with I'd prefer to go with that and swap out the 2 good ones if I can.
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Never mind. Did a search then ordered 3 from that ES link. They don't look difficult to replace either.
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Everyone is saying Honeywell SS41 in the forums, and I have them ordered but a friend told me he might have some hall sensors. If they aren't SS41s but operate in the same voltage and current range could I use them? I had a look at a few data sheets for generic Chinese hall sensors like you see on eBay, most are the same 4.5-24v and are 25mA max output current. How important are the other parameters like the switch on and off times? I would think if it mattered I would need 3 matching sensors and I doubt a motor made in China has Honeywell parts, it would have generic Chinese sensors so the SS41 is probably not a match for the other 2 and it is recommended. So, besides them being cheap Chinese parts (like those in the motor now lol) is there any reason not to use them if the electrical characteristics are the same as the SS41's? Assuming he can find them....
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At maximum rpm, each of the hall sensor will be switching high and low ~120 times a second, so the switching on and off time might make a slight difference, but I don't suppose you would notice it.
Alan
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My buddy found a bag of OH137s. Electrical characteristics are the same as the SS41, it's just the switching times are a bit faster. Shag it, I'm putting one in. Halfway there. I'm doing this at work so it will probably take all day, I can only work on it when I'm not busy. From 6 to 9 is dead here but now my phone starts ringing lol.
Had to take out the stator to get at it. Going to ask for help putting it back in, don't want to chip a magnet. Had to chisel the old sensor out with a small screwdriver, was glued in there good. I'm not going to replace all 3 due to the effort, it was tough not seperating the plates for the stator electromagnets while chipping away. I'll take my chances with the timing being off a fraction of a microsecond.
Oh, and there are 40 magnets for anyone who was wondering.
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Got the new one in, the one with the green heat shrink. Seems to work fine. One pole of a magnet turns it on, the other turns it off. Now to glue it in, tie down the wires, clean all the old glue/silicone off everything, resilicone it and finally reassemble. Hours of work left. Ugh.
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Got it all back together. Once I finished I thought I maybe should have checked everything one last time before siliconing around the controller and screwing it all together.
Now that I tested it I really wish I had!!! Doesn't work, same problem. Still runs, but not until I'm doing about 7km/hr and it vibrates and reduced power.
When I put the stator in it slammed in spite of my being careful. It went from no force to tug of war in an instant. I'm hoping I just scrunched a wire or something when I did. I gave it a quick visual inspection but I was looking for magnet chips, not wiring issues. That or the hall sensor I used isn't suitable in some way. The SS41s will be here in a few days I hope anyway.
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When I tested it it was with the motor apart and holding a magnet in my hand, I really should ha e tested it with the stator in place and the rotor magnets. That's how you learn, by screwing up.
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Opened the controller, getting a signal from the three hall sensors so that part is working.
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Are you sure that the phase wires were refitted in the correct order?
Look carefully on the controller PCB and see if you can see the colours printed for each of the phase wires.
Alan
This might help:
(http://www.arhservices.co.uk/GoldenMotor/Smart%20Pie/Newsinewavecontroller_zps9074e78f.JPG)
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Yes, took pics when I was taking it apart to be sure.
Should I be seeing 2 on at a time? I have the controller open now and am moving it a bit then checking and occasionally the yellow will be on with the green or blue, I haven't seen the blue and green on together. Yellow is the one I replaced.
I'm going home for the day now, tomorrow I'm going to open the other side so I can see the magnets and move it one at a time writing down which is on or off, see if there is a sequence or just a jumble of signals. Kinda hard to do that when I'm guessing where they are lol.
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Perhaps the Hall sensor you have used works with opposite magnetic polarity? If so, it might be closed when it should be open (and vice versa). ::)
Alan
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Should I be seeing 2 on at a time? I have the controller open now and am moving it a bit then checking and occasionally the yellow will be on with the green or blue, I haven't seen the blue and green on together.
It looks like you should, check out the six step sequence on this three phase motor animation:
(http://www.arhservices.co.uk/GoldenMotor/Three%20phase%20motor_zps74akxbas.GIF) (http://elabz.com/brushless-dc-motor-with-arduino/)
Alan
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When I tested it by hand before putting it together they would all turn on and off with the same poles.
There was some info on the Honeywell data sheet re magnetic characteristics that wasn't covered on the other, the problem with data sheets from different manufacturers. I'm assuming it's the part for now, hoping the SS41s get here soon so I can try them.
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Look what came in the mail! 3 Honeywell SS41s. I'll put them in tomorrow and see what happens.
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I put an SS41 in there, partially assembled the motor, checked am getting 3.24v or 0.01v on the yellow lead depending on where the motor is. Continued assembling motor, hooked everything up and......
.....same problem. Throttle does nothing until the wheel is moving about 7km/hr and it vibrates when it does move. I didn't ride it so I can't speak to the reduced power but I'm sure that is there too, I haven't put the freewheel back on yet.
So I opened it up again and double checked, still getting a 3.22-3.24v signal on all 3 wires depending on motor position. I checked for continuity in the motor windings, no problem there. I think it wouldn't work at all if there was a problem, right?
Now what? Does the fact I'm only getting a 3v signal have anything to do with it? I would think none of them would work if that was it. Can it be the controller?
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What voltage do you have between the Red and Black Hall sensor feed wires?
I would expect it to be between 4.5~5V.
Also make sure that the five hall sensor contacts are correctly seated inside the connector and have not been pushed out of the connector housing. If this has happened, they might be making a connection when you push the meter probe into the rear of the connector and losing the connection when the probe is removed again. ;)
Check the motor windings by removing the controller and clamping the axle in a vice etc. and then short together the Yellow and Green Phase wires and feel the resistance preventing the wheel from turning.
Do the same teat with the Yellow and Blue and Blue and Green wires to confirm the braking effect is the same on all three pairs.
If one combination is noticeably different to the other two combinations it would indicate a problem with the stator windings or one of the connecting wires.
If everything checks out OK I suspect the controller may have been damaged when the Hall sensor failed. :(
Alan
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Connector looks good, resistance seems the same for all three short combinations, but to be honest I'm not sure I felt much of anything beyond the normal resistance from a dead stop. I tried it with power applied and not, same either way.
This is where I am now. When I test on the connector for the hall sensors I get 4.2v on the red wire and either 0.01v or between 3.2 and 3.24v on the yellow, blue and green wires as I rotate the wheel. If I disconnect the connector and just check the pin for the red wire sticking out of the board it reads 4.6v. Each phase wire for the motor shows 0.06v at rest. When I apply throttle I hear a faint click, either in the controller or the motor itself, hard to say which but no other response besides a green flashing led on the controller board. Checking the phase wires in this state shows the same 0.06v on all three. I release the throttle, spin the wheel up by hand and apply throttle and cruise control so my hands are free and check again. Same 4.2v on the red wire for the hall sensors power and 1.6v on each signal wire. I assume that's because they are on half the time. Checking the phase wires for the motors is the same, 26v on each, half the supply voltage.
What can it be? From the voltage when running looks like everything is working isn't it? Or no because the stator coils are all one so the three contacts will all be the same voltage?
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Would it hurt anything if I disconnected on phase wire at a time and tried to run the motor and see if each post is getting power?
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I don't think it will cause a problem, as long as you don't accidentally short out the terminal or allow the end of the loose wire to touch any of the controller components, as the clear protective coating is very easy to pierce.
Alan
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Wish I had an oscilloscope. :-\ I disconnected each wire one at a time. At a stop each wire reads 0.06v. With the yellow disconnected the post reads the same when off. Hand spin the motor, apply throttle and cruise control, the blue and green read 26v, the yellow wire 26v, the yellow post 6v, varying by approx 0.5v once or twice a second.
With the blue and green wires off (one at a time) I was unable to get the throttle to engage at all. While the wheel was spinning with the throttle held down (but as I said no power being applied from the motor) all wires and the disconnected post were showing 26v for both blue and green being disconnected.
If I had someone here to help I'd test what happens with the braking (it vibrates when I brake too) but I just don't have enough arms.
So what does that mean engaging with the yellow off but not the other two? And the mismatch in voltages on the posts?
I've been reading all afternoon about controllers and one site said something about controllers blowing when a hall sensor fails and you give throttle from a dead stop. Exactly the conditions I experienced. I had just gone up a fairly long but not steep hill. I can't imagine the motor was hot, I had just left the house and it was about 6 degrees out. I stopped just fine and went to go and nothing. Kicked with my feet and it came on.
If it was just a sensor why does it have to be faster than 7km/hr to engage? Wouldn't the problem be limited to trying to move when the magnets were not in the right position? How would the speed be a factor? Any motion should line the other 2 phases up for the motor to engage. Or has the sensor driven mode failed completely and the motor only runs in sensorless mode which only cuts in about 7km/hr assuming this controller has sensorless mode? And the vibration is due to something being wrong on the yellow phase, initially caused by whatever blew the hall sensor? Or maybe the controller went first and took the sensor with it?
My head hurts lol. Im leaning towards buying another controller (my third) and trying that. I've only got a bit over 400kms on it, disappointed in the failure rate. Did I get a lemon or do these things break a lot?
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Crap, the controller is $175 now!!!!!!
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Is your wheel still under warranty? If so you shouldn't have to pay for a replacement.
If the hall sensor had been intermittently faulty from new it might account for why both of the controllers have failed.
Now you have replaced the Hall sensor it will hopefully be OK with a replacement controller.
If the controller is only working on two of it's three phases it would definitely explain the rough running. It's like a three cylinder motor only running on two cylinders.
Alan
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Yes, it's still under warranty. I'm going to refer Gary to this thread.
I'm no expert but it does seem that the controller is the issue now, that 6v reading on the yellow post...
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New controller is on the way, Gary sent it Monday. I won't see it till next week though. Yay Canada Post! Lol
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Got it today. Had to switch all the connectors because it's a new type apparently but it seems to work. I only tapped the throttle once and it started spinning smoothly then I stopped it again. I'll know for sure all is well when I ride to work in the morning. Thank you for all your help Alan.
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It's good to hear that the controller has cured the problem, hopefully the problem will not reoccur now you have also replaced the Hall sensors.
Did you have to change just the phase wire connections or was the hall sensor connector different too?
(http://www.arhservices.co.uk/GoldenMotor/emoticons/fingerscrossed.GIF)
Alan
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Both. The hall sensor connector already had short bits of colored wire attached though, all I had to do was splice the old wire to the ends and heat shrink it.