Mid drive motor pedal sensor failing

[bananas]

Hi, can any of you help, I've got a TongSheng TSDZ2 mid drive motor 750W. The pedal assist has recently started cutting out as I'm pedelling. There is still power, but only coming through intermitently to the motor .
I tried a new battery and that made no difference.
So I assume its an issue with a pedal sensor. Does anyone know where it is and how I can fix it?

 

[stratohunter]

How exactly is the intermittency of power delivery? If it is like sharply on and off then I'd check for a loose connector first. If the torque ramps up every time it comes back, it's more likely the torque or pedal sensor.

 

[endlessolli]

....This displacement is connected to a stain gage which changes electrical resistance. Voltage = current X resistance.....

This is not the case for the TSDZ2. Here the displacement is measured via a Hall Sensor and a current provided by the Hall-Sensor is the signal which correlates to the torque. This works fairly reliable.
So, in this case, I doubt that the torque-sensor is the culprit.

@bananas:
How many km did you ride with the motor already?
Did you change the setup recently?
Do you use factory firmware or opens source firmware?

Esp. the factory firmware is sometimes very sensitive to the distance of the magnet to the speedsensor.
Weired things can happen - for to small a distance as well as too wide.

Search this forum - there is really a ton of information about this motor.
Also a good starting point is https://github.com/OpenSourceEBike/TSDZ2_wiki/wiki/FAQ

 

[bananas]

Thanks for the help I'm just getting through your replies and will answer, but before I forget it may be important to note the motor provides power only when the pedal is at 11 through to 4 (if u imagine a clockface wirh 12 begin at the top of the pedal circle).

 

[amberwolf]

It may not be relevant, but the TSDZ2 has had mechanical crankshaft failures near / at the torque sensor cutout. If you can get to that area on yours, you might examine it for cracks. A crack could cause strain across the area to be relieved during some portions of rotation vs others, and cause differing response throughout rotation.

One example with pics
https://endless-sphere.com/forums/viewtopic.php?f=49&t=115972&p=1714021&hilit=tsdz2+crack%2A#p1714021

As I don't have direct experience with the system, I don't know if your symptoms could point to that sort of issue; Endlessolli and Stratohunter know much more about them.

 

[endlessolli]

To be clear, are you ruling out the torque sensor in this application? If so, what is the basis for your determination?
These torque sensors are reliable? Always?

Whoops, here's one that isn't:
https://www.youtube.com/watch?v=cOxYphMKx_Y

I am not ruling out - just based on my experience w these motors and the problem-description I think other things are more likely.
(The video you posted shows a sensor giving a too high signal - that can happen i.e. when the strain area is cracked - something that happens w/ these motors when too much load is put on the pedals - see amberwolfs link. But the problem in this thread is intermittent support, not too much support and I never heard that that crack causes intermittent failure)
But in any case, this 4 to 11 only support is really odd.
My guesses:
It could be the coils submitting the Hall-Signal are ‚wobbling‘ / not aligned anymore, or it could be something off with the PAS Hall and or its magnets.
Or something else :?

 

[bananas]

I am not ruling out - just based on my experience w these motors and the problem-description I think other things are more likely.
(The video you posted shows a sensor giving a too high signal - that can happen i.e. when the strain area is cracked - something that happens w/ these motors when too much load is put on the pedals - see amberwolfs link. But the problem in this thread is intermittent support, not too much support and I never heard that that crack causes intermittent failure)
But in any case, this 4 to 11 only support is really odd.
My guesses:
It could be the coils submitting the Hall-Signal are ‚wobbling‘ / not aligned anymore, or it could be something off with the PAS Hall and or its magnets.
Or something else :?

Do you have a picture or diagram that shows where the coils and the PAS Hall is on the motor so I can have a fiddle ?

 

[endlessolli]

Pls refer to the faq link in my 1st post.
Additionally, there are video-instructions and other useful information here:
https://pswpower.com/pages/download
Check esp the ones woth torque-sensor in their name

 

[bananas]

Pls refer to the faq link in my 1st post.
Additionally, there are video-instructions and other useful information here:
https://pswpower.com/pages/download
Check esp the ones woth torque-sensor in their name

Thankyou

 

[bananas]

Watching the torque sensor video I wonder if the crank shaft is slightly misaligned . I did have to have my crank arms replaced as the left (tongshen ) arm was loose as the internal bore where it fits over the crank had worn away making the thing wobble for a few months.
I'll take a look but I won't be confident to take the motor apart I don't think I have the tools. Do u do repairs via post ? Or are u located near halifax ?

 

[endlessolli]

Watching the torque sensor video I wonder if the crank shaft is slightly misaligned . I did have to have my crank arms replaced as the left (tongshen ) arm was loose as the internal bore where it fits over the crank had worn away making the thing wobble for a few months.
I'll take a look but I won't be confident to take the motor apart I don't think I have the tools. Do u do repairs via post ? Or are u located near halifax ?

If by you you mean me - I am in Germany...
You need to find someone in your area.
And yes - it is quite fiddely to do - esp. putting it back together....