Firstly, thwnk you so much for sharing this! It could happen to anyone and it takes great courage to own up and share the findings. Nothing to be embarrassed about. It shows you are a great tech and have the knowledge to back it up. Thanks again for all the videos you go out of your way to make ❤
Great learning in the method of doing things ! The beauty of being an electric motor, it only spun the other way around. Imagine rebuilding an ICE engine and putting pistons upside down and then cranking the starter. motor would not be usable anymore ...
interestingly (or not lol) some internal combustion engines can actually run backwards! Two stroke engines that have timing fixed only by piston position, ie those in a say a chainsaw or very large ocean going ship, can accidentally be started and run backwards 🙂
The Zoe eMachine is a sperately excited brushless 3phase design, where the rotor field is also electromagnetically generated rather than being provided by permanent magnets, all of which you already know. However unlike the stator, which is stationary (duh!) and has an AC rotating magnetic field generated by the 3 phase inveter to which it is attached, the rotor, which rotates (again duh!) has a DC non rotating magnetic field, which rotates because the rotor iself is rotating. So, when you swapped +ve and -ve on the rotor exitation wires, you made all the North poles south poles, and all the south poles north poles, so when the inverter applied the stator field at quadrature to the rotor field, the rotor gets pulled the opposite way to that intended. The same effect can be done by simply swapping any two of the 3 phase cables for the stator (because looping round A->B->C is looping round A->C->B backwards!). Now the motor itself does not care in the slightest if a pole is North or south, but the inverter, and critically the resolver most certainly do. I won't go into all the details of Field Oriented Control (FOC) here, but surfice to say, when you put the car in "DRIVE" and apply the accelerator, the inverter control strategy is tying to generate a "forwards" stator field, so as soon as the rotor actually turns backwards it spots the problem and turns off, simply because if the reversed change in phase inductance comensurate with the rotor going the wrong way. Imagine trying to ride a bike with the steering reversed to try to understand the problem, you want to go left, you turn the handle bars left, and the bike starts going right, so your brain of course adds yet more left input the handlebars to try to go left, and the bike goes even more right! Eventually, you have steered all the "left" available to steer, just as the motor control inverter has added as much "turn forwards" as it can, and so it shuts down. This is why you get little "pulses" of movement in the incorrect direction before the control system saturates and trips the error and turns off!. Before the rotor has actually moved, the inverter has no way of knowing the wiring and hence rotor magnetic poles are reversed, so turning it off and on again resets the system until you try to move again 🙂
Yep, it matters peanuts if it's push or pull, the rotor just turns the same direction as the rotating field of the stator. So phases must be fired the other way. If that position sensor was rotated 90° (2 pole pairs motor) things would go back to normal.
If you build power supplies for valve projects the secondary transformer windings have a dot at one end of each winding. If you are combining windings these are very important. I suspect this is similar what you are seeing here. Another example is flying. Your instruments say one thing, your gut feeling says another. To stay alive follow the instruments. Follow the instructions and do not over think. Unless you like the smell of burning. I've cocked up like this myself in various ways. I guess we all have.
Great learning video.Hi i was going to buy a zoe 50kw that was involed in a shunt but the airbags have been deployed. Is it going to be a nightmare to fix i should i take a gamble on it
Hi don’t know your skill level but parts cost can add up quickly and the airbags going off adds to the cost. I don’t really do bodywork as powertrain issues are my thing but budget accordingly. Much better if airbags haven’t gone off, can end up in a nightmare of modules needing reprogramming to remove crash data. Cheers
It is not turning the opposite way, the rotor field and the stator fields are shifted, as the rotor field got reversed. This leads to the drive electronics applying a stator field that doesn't match the rotor field for best and smooth torque, which it then detected once it applied stator current. The reversed rotor leads are equivalent to rotating the position sensor to half the distance of a motor pole.
Ok does the dash go black and when you go back to the car it’s on 97% or it sits charging with the dash showing 97% and dashes for the time and you stop it? There was a BMS update for early 22kwh Zoe’s but I believe that’s only for earlier ones. Could be the battery is out of balance - keep draining and fully charging (letting the car finish and dash go black) and see how that goes. As it’s under battery lease it’s Renaults responsibility to maintain it but you’d have to get a garage to check the battery health (soh). If you can get 80 ish miles out of it then the battery is ok. Cheers
Indeed, for rotor excitation. It is a 3 phase ac motor so it’s not a brushed dc motor. It doesn’t contain magnets so has to get power on to the rotor somehow. I recently stripped a motor from a car that had done 116k and the brushes were around 25% worn. Cheers
Firstly, thwnk you so much for sharing this! It could happen to anyone and it takes great courage to own up and share the findings. Nothing to be embarrassed about. It shows you are a great tech and have the knowledge to back it up. Thanks again for all the videos you go out of your way to make ❤
Thank you - it’s certainly one I won’t forget.
Great learning in the method of doing things ! The beauty of being an electric motor, it only spun the other way around. Imagine rebuilding an ICE engine and putting pistons upside down and then cranking the starter. motor would not be usable anymore ...
interestingly (or not lol) some internal combustion engines can actually run backwards! Two stroke engines that have timing fixed only by piston position, ie those in a say a chainsaw or very large ocean going ship, can accidentally be started and run backwards 🙂
The Zoe eMachine is a sperately excited brushless 3phase design, where the rotor field is also electromagnetically generated rather than being provided by permanent magnets, all of which you already know. However unlike the stator, which is stationary (duh!) and has an AC rotating magnetic field generated by the 3 phase inveter to which it is attached, the rotor, which rotates (again duh!) has a DC non rotating magnetic field, which rotates because the rotor iself is rotating. So, when you swapped +ve and -ve on the rotor exitation wires, you made all the North poles south poles, and all the south poles north poles, so when the inverter applied the stator field at quadrature to the rotor field, the rotor gets pulled the opposite way to that intended. The same effect can be done by simply swapping any two of the 3 phase cables for the stator (because looping round A->B->C is looping round A->C->B backwards!). Now the motor itself does not care in the slightest if a pole is North or south, but the inverter, and critically the resolver most certainly do. I won't go into all the details of Field Oriented Control (FOC) here, but surfice to say, when you put the car in "DRIVE" and apply the accelerator, the inverter control strategy is tying to generate a "forwards" stator field, so as soon as the rotor actually turns backwards it spots the problem and turns off, simply because if the reversed change in phase inductance comensurate with the rotor going the wrong way. Imagine trying to ride a bike with the steering reversed to try to understand the problem, you want to go left, you turn the handle bars left, and the bike starts going right, so your brain of course adds yet more left input the handlebars to try to go left, and the bike goes even more right! Eventually, you have steered all the "left" available to steer, just as the motor control inverter has added as much "turn forwards" as it can, and so it shuts down. This is why you get little "pulses" of movement in the incorrect direction before the control system saturates and trips the error and turns off!. Before the rotor has actually moved, the inverter has no way of knowing the wiring and hence rotor magnetic poles are reversed, so turning it off and on again resets the system until you try to move again 🙂
Yep, it matters peanuts if it's push or pull, the rotor just turns the same direction as the rotating field of the stator. So phases must be fired the other way. If that position sensor was rotated 90° (2 pole pairs motor) things would go back to normal.
I guessed correctly!😂🎉
Every day is a school day.
Yeah, the beautiful simplicity of electric motors even rather odd French designs 😊
Oddly too that the part failing most on these motors appear to be made in Germany :_)
If you build power supplies for valve projects the secondary transformer windings have a dot at one end of each winding. If you are combining windings these are very important. I suspect this is similar what you are seeing here. Another example is flying. Your instruments say one thing, your gut feeling says another. To stay alive follow the instruments. Follow the instructions and do not over think. Unless you like the smell of burning. I've cocked up like this myself in various ways. I guess we all have.
Interesting analogies, thanks.
Great learning video.Hi i was going to buy a zoe 50kw that was involed in a shunt but the airbags have been deployed. Is it going to be a nightmare to fix i should i take a gamble on it
Hi don’t know your skill level but parts cost can add up quickly and the airbags going off adds to the cost. I don’t really do bodywork as powertrain issues are my thing but budget accordingly. Much better if airbags haven’t gone off, can end up in a nightmare of modules needing reprogramming to remove crash data. Cheers
It is not turning the opposite way, the rotor field and the stator fields are shifted, as the rotor field got reversed. This leads to the drive electronics applying a stator field that doesn't match the rotor field for best and smooth torque, which it then detected once it applied stator current.
The reversed rotor leads are equivalent to rotating the position sensor to half the distance of a motor pole.
The car was jumping forward in reverse and visa-versa…
@@garycevrepairs When is your dissertation on 3 phase synchronous motors finished?
As my daughter would say “weird flex but ok”. Especially as you’re saying something didn’t happen when it did…
A question if I may, why would my zoe stop charging at 97%?
Hi does it always stop at 97% and what year is it?
It's a 2015 only had it 2 weeks but both times I've tried to fully charge it it's stopped at 97% once on a 22kw once on a 7kw
What is the range on a full charge? Is it battery lease? Doesn’t sound quite right?
At 97% it showed 60 miles I've driven 50 miles to work and back and it's still showing 30 miles with 45% remaining
And yeah the battery is on lease
Ok does the dash go black and when you go back to the car it’s on 97% or it sits charging with the dash showing 97% and dashes for the time and you stop it? There was a BMS update for early 22kwh Zoe’s but I believe that’s only for earlier ones. Could be the battery is out of balance - keep draining and fully charging (letting the car finish and dash go black) and see how that goes. As it’s under battery lease it’s Renaults responsibility to maintain it but you’d have to get a garage to check the battery health (soh). If you can get 80 ish miles out of it then the battery is ok. Cheers
😅😅
Of course it should matter in a brushed DC motor lol
It’s not a brushed dc motor (lol). It’s a 3 phase ac motor but with a wound rotor, therefore magnetless. Cheers
@@garycevrepairs Well yeah, that's true. It is still a DC motor with brushes :D The same effect would similarly happen with a brushed DC motor!
It’s not a dc motor, the stator has 3 wires not 2. The 2 wire rotor replaces the magents. It has a 3 phase controller !
Carbon brushes? Seriously?
Indeed, for rotor excitation. It is a 3 phase ac motor so it’s not a brushed dc motor. It doesn’t contain magnets so has to get power on to the rotor somehow. I recently stripped a motor from a car that had done 116k and the brushes were around 25% worn. Cheers