Tranzx 6 magnet RPM sensor (back removed)
- Thread starter johnRN
- Start date
It's a hall sensor with a capacitor to remove interference. The black wire is ground, red 5v and the third wire is the signal wire that should switch when a magnet with the correct field orientation passes in the correct direction.
Often, either a pull-up or pull-down resistor is needed to switch the hall sensor back to its original state. That resistor could be directly attached to the sensor, though not in your case, or it could be in the controller pcb, or it could be integrated into the sensor itself.
So, connect 5v and check the resting state of the signal wire. If it's high, connect a 5k or 10k resistor between the signal and 5v, then wave the magnet around the sensor until you find the direction and orientation that makes it switch. If the signal rests low, put the resistor between ground and signal. You can try without the resistor first, but if you get inconsistent results, you need it for testing.
Often, either a pull-up or pull-down resistor is needed to switch the hall sensor back to its original state. That resistor could be directly attached to the sensor, though not in your case, or it could be in the controller pcb, or it could be integrated into the sensor itself.
So, connect 5v and check the resting state of the signal wire. If it's high, connect a 5k or 10k resistor between the signal and 5v, then wave the magnet around the sensor until you find the direction and orientation that makes it switch. If the signal rests low, put the resistor between ground and signal. You can try without the resistor first, but if you get inconsistent results, you need it for testing.
Thanks for that ...I was intrigued as to how this worked ...possible cause of problems on my bike, which has display powered up, and front/rear lights, but no power to the motor ...could also be the brake switch/controller mosfets/motor hall sensors I guess.
I doubt that the sensor would cause problems unless the magnet is too far away or too close. Everything else has to be tested. Start by checking that there's 5v on the red wire. If not, the controller isn't switched on even if the LCD is. When MOSFETs blow, you normally get a tick or twitch from the motor when the controller tries to give power, or the battery cuts out due to one being shorted.
The cause of the problem is often indicated by the circumstances at the time of failure. It's not possible for an ebike to destroy anything, while it's parked in a clean dry garage or house, so what happened?
I must admit that there were no signs of damage or movement of the sensor in relation to the magnet/sensor separation, and there had previously been no indications of power issues on the previous day ...OK the day before..then not OK. No error messages showing on the display.
I think that checking for 5V is a good plan, just incase the controller is not providing 5v. Maybe check the controller mosfets for a short?
I do have 2 of these bikes (the other also not working! ...) so I could try and swap controllers.
I think that checking for 5V is a good plan, just incase the controller is not providing 5v. Maybe check the controller mosfets for a short?
I do have 2 of these bikes (the other also not working! ...) so I could try and swap controllers.
Battery in good condition ...did a discharge test not that long back ...controller possibly OK, but need to check mosfets ..also check hall sensors in the motor. There is a TMM4 torque sensor on the back wheel axle, which presumably coordinates with the RPM sensor to give a smoother 'assist' response. I only latched on to the RPM sensor, thinking that may dirt/stones/rubbish off the road might have caused some damage ...and I do have a spare if needed. To be honest, I used to be a structural cinsulting engineer, so my electrical/electronic experience is limited here ..you clearly have a better insight than myself!
Isn't that TranzX's M25 motor? IIRC that was notoriously unreliable, so much so it was routinely/frequently replaced in the US and didn't stay in production very long.
Have you had the bike(s) tested using TranzX's Logix plug-in diagnostics? I doubt you'd be able to fathom much without it, and getting any parts for that motor/system is IMHO quite doubtful now.