Heads up (warning) and q. About selflearning wire

Hulken

10 mW
Joined
Nov 23, 2022
Messages
20
Hi. I would like to leave a note on a potential dangerous situation with trottle cables. The trottle ground become broke and the non precense of ground results that the controller send the 5v direct to signal and the controller think you hit max trottle and send full avalible power to motor, so there it drove away without any driver in my backjard. Well it fell after a few meters and the wheel rotaded in air until i disconnect vcc.

It seems like about 7 smaller signal and ground wires has just broke and become lose from circuit board. I did just desolder every wire that have no purpose to me.
But the selflearning wire in one end was loose and was not posibiltie to trace.
But I think it just should go to ground. Is this the usual solution in selflearning circuit one signal to ground to aktivitete.
 
Hulken said:
Hi. I would like to leave a note on a potential dangerous situation with trottle cables. The trottle ground become broke and the non precense of ground results that the controller send the 5v direct to signal and the controller think you hit max trottle and send full avalible power to motor, so there it drove away without any driver in my backjard.


Yes, this is unfortunately a well-known problem with virtually every typical controller.

Installing a pulldown resistor (10-20kohm) at the controller PCB from signal to ground will prevent this from happening, probably without significantly affecting the controller performance or behavior.

Not done by any controller manufacturer except a single VESC manufacturer, AFAIK, for unknown reasons, but users have modified their controllers similarly to stop this problem.

THere are other ways to design controllers to avoid this problem, and some of them use one or more of the methods. The simplest, when they are hall-signal-input controllers, but the least effective*** is to write the software so it ignores any throttle signal above it's maximum (usually 3.something volts, sometimes as high as 4.2v), since usualy with a completely failed ground the signal will rise all the way to the throttle supply voltage.

***this doesn't work for cases where ground is just mostly broken, and signal doesn't get pulled up above the limit, but does become stuck near it.

Another solution some controllers have used (vectrix, etc, IIRC) is to use two throttle sensors, one of which goes from low voltage to high, with the other inverted. If the controller doesnt' detect them tracking each ohter within a certain tolerance, it shuts down for a throttle failure.

But the selflearning wire in one end was loose and was not posibiltie to trace.
But I think it just should go to ground. Is this the usual solution in selflearning circuit one signal to ground to aktivitete.
That's probably correct, if you have already traced the other end of the learning wire to a signal PCB pad (rather than 5v or ground).
 
amberwolf said:
Hulken said:
Hi. I would like to leave a note on a potential dangerous situation with trottle cables. The trottle ground become broke and the non precense of ground results that the controller send the 5v direct to signal and the controller think you hit max trottle and send full avalible power to motor, so there it drove away without any driver in my backjard.


Yes, this is unfortunately a well-known problem with virtually every typical controller.

Installing a pulldown resistor (10-20kohm) at the controller PCB from signal to ground will prevent this from happening, probably without significantly affecting the controller performance or behavior.

Not done by any controller manufacturer except a single VESC manufacturer, AFAIK, for unknown reasons, but users have modified their controllers similarly to stop this problem.

THere are other ways to design controllers to avoid this problem, and some of them use one or more of the methods. The simplest, when they are hall-signal-input controllers, but the least effective*** is to write the software so it ignores any throttle signal above it's maximum (usually 3.something volts, sometimes as high as 4.2v), since usualy with a completely failed ground the signal will rise all the way to the throttle supply voltage.

***this doesn't work for cases where ground is just mostly broken, and signal doesn't get pulled up above the limit, but does become stuck near it.

Another solution some controllers have used (vectrix, etc, IIRC) is to use two throttle sensors, one of which goes from low voltage to high, with the other inverted. If the controller doesnt' detect them tracking each ohter within a certain tolerance, it shuts down for a throttle failure.

But the selflearning wire in one end was loose and was not posibiltie to trace.
But I think it just should go to ground. Is this the usual solution in selflearning circuit one signal to ground to aktivitete.
That's probably correct, if you have already traced the other end of the learning wire to a signal PCB pad (rather than 5v or ground).

Amberwolf in greatful for your time, thank you.

Well its a cheap controller 150$ 72V, 80amp. https://www.fruugo.se/48v-72v-3000w...4iNhIm2OFFBFyK2RZigtNGhLLrtVXeyAaAtXFEALw_wcB
I will in this case just desolder every cable, and solder on new higher quality that wont break. And or secure with 2 ground trottle wires on different pads.

Well the one end on the learningwire shows 5v.
the learning wire never worked from start and when I first opened the controller just after tested for 10mins the wires already was loose.
it looked like the controller was a repared or manufacured in very dirty enviroment, but the components like consensators also differ in color so probably repaired then sold again. So I have no clue more than ground it didnt start any function at all to ground this 5v selflearning wire.
But anyway it seems my problem with the stuttering that is my reason to try selflearning wire is on either hallsensorwire or phasewires from motor to controller. Becurse it just started to drive the motor att great toque and speed just fine when I did move the cable a bit then started with problem after few km. So I will just cut it and replace it with better quality and thicker for phases.

Is there a reason hallsensornwires and phasewires are in same cable or can I just separate them?
 

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Oki i will use PTS-HF Nexans signalwire 4x2x0.6 mm, White as hallsensorwire and 10mm² for phase wires.
Leta get started
 

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I have had a few situations plugging in the learning wire and almost got my arm ripped off once. Ebikes for children should be supervised by an adult. Now I barely engage and quuckly pull apart the white wire of wisdom
 
Hulken said:
Is there a reason hallsensornwires and phasewires are in same cable or can I just separate them?
Because it's simpler and cheaper for them to do this--they only have to run one cable thru the motor axle (or other entry point), and keep one spool of cable around for that.

It's not uncommon for phase and hall to be separate cables from the controller, except for those that use one of the various "standards" of water-resistant (Higo, Julet, etc) motor cables, but at the motor they are almost always one cable out of the axle, even if they have separate connectors.

Almost always, the cables themselves are made to be as skinny as possilbe to fit thru axles, etc., so they are usually interleaved hall/signal/phase wires such that small wires are embedded between and around larger phase wires, which leaves the halls more vulnerable to interference from phases, though with these very small cables they're usually for small lower power motors and so have less current to create induced currents, so less worry.

In higher current systems, with bigger motors and controllers, it can make some difference to operational problems to separate phases and halls (though it may not fix a problem, depending on it's cause).

Also, see this post about wiring:
https://endless-sphere.com/forums/viewtopic.php?f=6&t=97945&p=1747877&hilit=ground#p1747877
 
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