Hi Gary, it is the result of a heavy large current flowing between the rotor and case. We have seen it on railway electric units and is cured by insulating the bearings or ensuring the rotor is earth by a brush on the axle. Now a battery car is not a train but the view of the pitting does show a low voltage , heavy current flow due to a voltage difference between rotor and stator. A rotating connection of the rotor shaft to the motor case will eliminate the damage being done to the bearing. So, one bearing needs to be insulated to stop the circulating current flow ( induced) through the rotor and case.
Tesla had this problem in early motor designs. This was solved around 2017 with adding specific pathways for the current to prevent bearings being eroded.
Great video. Thanks for sticking with this investigation and for so many knowledgeable people to get involved and contribute. I wonder what Renault think? I'm now keeping an ear out on my wife's Zoe.🤔🤔
Thanks for that - Tesla had similar with early Model S ( approx 2-3 years) - they replaced many motors under warranty . The fix was some kind of carbon “ shield “ on the rotor end. Memory’s going 🙄. Will do a quick search .
They used stationary motor bearings on a motor used in a vehicle that moves. We had similar problems when designing a DIY electric car 15 years ago and used a motor designed to be stationary. The motor bearings got bad pretty soon by all the vibrations, potholes and centrifugal forces when changing vehicle direction and motor spinning fast at the same time. The marks on the bearings were almost the same as this. The solution was to equip the motor with much stronger bearings that have lateral support races or needle bearings and redesign the motor mounts.
eddy currents from the PWM frequency (and harmonics) of the VFD, a long-known issue with using them...some solutions use brushes to keep the current from flowing through the bearings, others use ceramic bearings.
Your man is right I have seen this in many industrial machines and the usual fix is to get zero potential across the bearing accomplished with carbon brushes on the rotor shaft to earth. More of a pita to get working than you might think.
Rotor discharge brush might help with static electeicity build up, but not with mirco welds. Weld is created by high curent, caused by induced current though motor shaft. For me, best couse of action is metal bearing on reduction gear side, and ceramic ball bearing with rubber seal on inverter side. Doing it other way round will damage bearings in gearbox.
You are doing really good job man👍 Even Renault R&D should watch this. In theory the metal sheld in the bearing might not provide a path for current through the shield as it does not contact both races, might be worth double checking this. but would be awesome solution if it solved this issue.
"Electro discharge machining (EDM) in bearings" refers to a phenomenon where electrical discharges occur within a bearing, essentially "machining" the bearing components by creating tiny pits and damage through the electric sparks, often caused by a build-up of shaft voltage that discharges across the bearing surfaces, leading to premature bearing failure if left unaddressed; essentially, it's the same EDM process used in manufacturing, but happening unintentionally within a bearing due to electrical currents in the system.
The Zoe uses the windings of the motor for the charging circuit. Wondering if because of how the damage is on one side of the bearing rather than in a line around it, the discharge is happening while the motor is stationary while charging rather than powered while moving
That's a good call and sounds entirely plausible to me, arcing through the bearing whilst running causes a distinctive lined pattern on the bearing races, a bit like the patterns you get from the old Spirograph drawing toys. This isolated pitting looks like it's happened whilst stationary.
Yes please ! You could also maybe discuss with other electric specialists that manage ZOE repairs. Such as EVCLINIC in Croatia and RevoltClub in France !
What sort of cost are we looking at for replacing these with screened bearings? I am thinking maybe a preventative replacement at a time convenient to me rather than waiting until they are rumbling and having to have a car transported.
I previously needed to order / specify motors for use with industrial AC variable speed drives. For larger motors I would always tell the motor manufacturer that they will be used for this duty, they would supply insulated bearings / shaft brushes to overcome currents induced in the motor shaft by the inverter switching frequency. I suspect Renault use the same inverter technology as an industrial VS drive so should take account of these potential issues and I’m very surprised that they don’t. It is interesting that Nissan Leaf motors have shaft brushes and don’t seem to suffer from the same issues. There should also be a common mode filter fitted between the inverter and motor.
I think my idea of buying a Zoe has ended. Your tales of woe have been most enlightening. Wonder if you've explored other EV mechanical problems? Your arcing theory is interesting. Could it also just be poor lubrication? I dread to think what the noise was like when this bearing was running.
You should lokk at the raceway in one of the better looking bearings. The key is finding the first signs of failure. The one you took apart is worn out much too far.
Iirc there was a period when satellites with gyroscopes were failing after solar flares, the investigation came to the same conclusion that a potential difference was causing arcing across the bearing, soon after they would seize.
The new Renault EVs (Scenic, Megane, R4, R5 E-Tech) all have, to my knowledge, engines without permanent magnets. I wonder if Renault has rectified this or this can still be a problem.
Take a look at the inner and outer races, if you see some fluting (lines perpendicular to the rotating motion) then this would be a sign of bearing currents.
Would the mysterious spring on the brush end of the rotor shaft act to equilise the case and rotor potentials, or does it just contact the static outer race?
I got bearings with metal shields to give another path for discharge. In any case if im fixing a car that’s done 100k miles then it’s likely the motor will outlast the car if it does another 100k! Cheers
Just thinking out loud here but are there any other common factors that you have noticed when dealing with these bearing failure cars other than the motor types. So for example the types of chargers i.e. Have the cars had a mix of charger types of are they mostly CCS or 40 kilowatt chargers.
I try to avoid bearings with cages when fixing my bike. Old bearings put in at the factory usually get the ball cages shredded over time which does nothing to improve rolling resistance or lubrication.
I don't believe discharging is the issue. There's easier ways for the rotor to ground out, through the output shaft for example. Those pits are classic for a bearing that's got too hot and has likely suffered false brinelling due to the affects of vibration. There's also something called rolling fatigue that occurs leading to fractures of the bearing surface, but that's usually more noticeable in the raceway than the balls. I think it's probably more just a case that those bearings are too lightweight for what they're doing, and possibly that this design of motor is more inclined to produce vibration. Permanent magnet I believe runs smoother. When you think about it it's actually amazing that these two little ball bearings last as long as they do given the speed of the rotor, and the fact they never receive any fresh lubrication or the cooling affect that would have if oil were pumped through the bearing as in an ICE.
In one of the EVTV Motor Verks (m.youtube.com/@EVTVMotors) videos Jack Rickard was discussing the reseon behind metal brushes on Tesla Model S motor rotor shaft. And it was there for exactly the same arc discharge reason. Apparently early Model S motors had a tendency to granade themselves too due to the charge build up and eventual discharge via the bearings.
Here is the exact bit in the EVTV Motor Verks "Hacking the Tesla Drive Train" video where Jack Rickard starts discussing the metal bushes/bristles near the rotor bearings in Tesla Model Ss Induction motor stator's housing: ua-cam.com/video/_rqMT3-Tlls/v-deo.html
Looks like the bearing inside my chinese made telescope mount. Can't believe how small and puny these bearings are for something that has to resist such high torque and rotational speed. Telescope weighs about 10kG and rotates a mere one revolution per day to keep up with the earth's motion.
Outside of any warranty issues....these cars are probably all out of warranty Renault's fix is to replace the whole motor....It would be interesting to know if the replacement motors have a different design
Surely this should be something that Renault are forced to carry out a Recall and replacement on the specific motor types as the motor is not fit for purpose. Has this been raised with the regulatory authorities?
@ but if it is an issue that can happen at any time- or if the vehicle were used as a taxi covering high mileage surely Renault would be liable for using a motor/bearing design that is not fit for purpose. Are you aware if anyone has raised the issue officially?
I heard of "hybrid bearings" where they use some ceramic material for the balls which will work as an isolator. Maybe that type of bearing would work better in these motors.
@@frippefrippe5760 I don't know, but the current would have to pass a gear first in that case? Maybe the gears could be affected but will take a lot longer before becoming an issue compared to the ball bearings.
Have you any advice for Zoe owners on how to extend the life of the bearings? Does driving style make any difference or charging speeds? My ZE50 has reached 93,000 miles without any problems with the motor bearings. 99% of my charging is overnight on a 7kW home charger and I tend to drive it efficiently avoiding harsh acceleration. Does gentle driving and slower charging help, or is this wishful thinking?
Gentle driving yes. It will lower the current going through the bearing and also reduce wear on the bearing anyway. Charging doesn't matter but it will preserve battery health.
I wouldn't be so quick to exclude charging. The Zoe uses the windings in the motor as a transformer during charging, so while the car isnt moving there's still power in the motor windings. This is also why the Zoe is louder during charging.
Not sure on charging, need to think about that more but gentler driving definitely increases the life. Lower power Zoe’s seem to suffer less from the bearing issues.
@@khalidacosta7133 Actually I think it is a pretty genius thing to do: saves weight on the charger circuit, uses components already in the vehicle to reduce cost. We have a 2015 zoe which has not had this issue (currently 135k km on it)
Why is there rust on the outer race? To me it looks like a car wheel bearing- classic water damage. If it's caused by eddy currents, you'd see the same pitting (more so) on the pinion gear teeth at the end of the shaft.
With it appearing to be only in one spot on each ball you have to ask - are the balls rolling or sliding ? If they are sliding there should be a continuous wear pattern around the surface of the race.
I suspected bearing currents long time. What i am curious is why some people replace motors multiple times. And some people can run really long on their motor. (Mine has gone 240000km for example on first motor, but the wifes r90 (identical) had motor changed at 50000km. Could it be that its the inverter that is the problem and not the motor? (the problem arrieses from the inverter not producing enough balanced 3 phase current, so it will not sum up 0v). That could explain the stories of people needing 2 motor swaps on the cars life (some inverters giving better 3 phase output than others)
I wondered if different charging regimes would impact wear differently, granny charger vs 7kW vs 22 kW? I assume the motor isn't used in CCS/DC charging?
I'm not sure if it is used for boost conversion, but after all it's still some windings but it's not a transformer. I think it is used as a reactor/ballast and the higher voltage is achieved in the motor inverter
Phase Gate Control, Of you rectify 230Vac, with a full brigde rectifier, you will get about 325Vdc, the rest can be done via phase gate Control in the inverter. At work our industrial converters produce 840Vdc from 600V input, you can step up this DCvoltage up to 1000V or even higher without changing the input
When I was choosing my first EV it was between Zoe & Leaf! Glad I went Leaf after watching your videos. The Leaf is liquid cooled on charger/inverter & motor housing. Those Zoe bearings have been cooked to death by motor winding heat, common mode & parasitic currents & possibly corrosion. They look black, never seen bearings like that before. Is it burnt grease or the metal? You didn’t show us the bearing races. Do they have fluting or similar damage? I’m shocked at this bad design fault but fascinated by the causes. Thanks for showing this.
The BIG issue with the leaf is the battery: it's is not cooled AT ALL (no liquid, no air, nothing) and it overheats during usage. People are reporting insane battery degradation after just a few years, we're talking 70% state of health or even lower after 5 years or less. Both the Leaf and the Zoe are terrible cars that won't last long unfortunately.
@ Your right of course. Zoe has great battery cooling but poor motors. Leaf has good motors but poor battery. Just for context though my Leaf has done 43,000 miles is 8 year old in March yet battery health is still 96% SOH. Secret is don’t let battery get hot! In the UK that’s rarely a problem & it’s only been charged using granny charger. ( 2 rapid charges). It serves me well & is great to drive. Next car will defo have liquid cooled battery & CCS.
@@Lesjaye 96% SoH after 8 years and 43,000 miles is quite impressive! How do you prevent the battery from getting hot though? As far as I know, there's no real way to do that with longer trips. Maybe your daily routine involves small trips?
@@nicnl255 Small trips 5 -10 miles daily, 30-40 miles once a week. It’s an early leaf with 30 kw ,3.1 kw ac charging which were deemed to be the worst for degradation. It’s a particularly good battery & I lucked out. If you do repeated high mileage & rapid charging it’s not the car for you.
I think the problem is that they are too small for the load they carry. The design of the motor needs rethinking. They will run hot and cool slow - which anneals the metal. This reduces the hardness. Once this happens the bearing starts to flat off in places and then once the surface has gone, the rest is much softer material and it pits totally.
Is it not more likely that these are just poor quality bearings and the surface hardening is failing? If it were electrical discharge through the bearing wouldn't it generate a more regular wear pattern? I bet someone deep inside renault is aware of this, especially if motors can fail inside the w'tee period and its costing them money. My desire for a ZE50 as a cheap second car is fading 😢 Excellent videos by the way 😊
I'd have expected the same pattern your describe from arcing during running, but someone has pointed out that the motor forms part of the charging circuit so arcing whilst stationary is a distinct possibility.
Maybe I was too much confident about my assumption I'm watching "Axial Flux Motors Explained: The Future of EV Powertrains?" from Munro Live At 3:52 it's about electric static charges and a part to preserve the bearings from them.
What do you think, should I cut open some more bearings to see if they are the same?
Do it :)
Yeah, if you find the time, please do 😊😅😂
Hi Gary, it is the result of a heavy large current flowing between the rotor and case. We have seen it on railway electric units and is cured by insulating the bearings or ensuring the rotor is earth by a brush on the axle. Now a battery car is not a train but the view of the pitting does show a low voltage , heavy current flow due to a voltage difference between rotor and stator. A rotating connection of the rotor shaft to the motor case will eliminate the damage being done to the bearing. So, one bearing needs to be insulated to stop the circulating current flow ( induced) through the rotor and case.
Tesla had this problem in early motor designs. This was solved around 2017 with adding specific pathways for the current to prevent bearings being eroded.
Really think you're on the right path and I have seen this on electric motors.very interesting thanks
Thanks 👍
Great video. Thanks for sticking with this investigation and for so many knowledgeable people to get involved and contribute. I wonder what Renault think? I'm now keeping an ear out on my wife's Zoe.🤔🤔
Thanks for that - Tesla had similar with early Model S ( approx 2-3 years) - they replaced many motors under warranty . The fix was some kind of carbon “ shield “ on the rotor end. Memory’s going 🙄. Will do a quick search .
They used stationary motor bearings on a motor used in a vehicle that moves. We had similar problems when designing a DIY electric car 15 years ago and used a motor designed to be stationary. The motor bearings got bad pretty soon by all the vibrations, potholes and centrifugal forces when changing vehicle direction and motor spinning fast at the same time. The marks on the bearings were almost the same as this. The solution was to equip the motor with much stronger bearings that have lateral support races or needle bearings and redesign the motor mounts.
Interesting insight, thanks!
eddy currents from the PWM frequency (and harmonics) of the VFD, a long-known issue with using them...some solutions use brushes to keep the current from flowing through the bearings, others use ceramic bearings.
Your man is right I have seen this in many industrial machines and the usual fix is to get zero potential across the bearing accomplished with carbon brushes on the rotor shaft to earth. More of a pita to get working than you might think.
Rotor discharge brush might help with static electeicity build up, but not with mirco welds. Weld is created by high curent, caused by induced current though motor shaft.
For me, best couse of action is metal bearing on reduction gear side, and ceramic ball bearing with rubber seal on inverter side. Doing it other way round will damage bearings in gearbox.
Interesting thoughts, thanks.
If it's electrical discharge, why does it take so long - maybe that's a secondary thing that only starts once the bearings start to wear.
Think it’s like micro spark erosion similar to the machining process
Mike, I was going to namecheck you for your thoughts, but you were here first. 🙂
You are doing really good job man👍 Even Renault R&D should watch this. In theory the metal sheld in the bearing might not provide a path for current through the shield as it does not contact both races, might be worth double checking this. but would be awesome solution if it solved this issue.
Thanks !!
"Electro discharge machining (EDM) in bearings" refers to a phenomenon where electrical discharges occur within a bearing, essentially "machining" the bearing components by creating tiny pits and damage through the electric sparks, often caused by a build-up of shaft voltage that discharges across the bearing surfaces, leading to premature bearing failure if left unaddressed; essentially, it's the same EDM process used in manufacturing, but happening unintentionally within a bearing due to electrical currents in the system.
The Zoe uses the windings of the motor for the charging circuit. Wondering if because of how the damage is on one side of the bearing rather than in a line around it, the discharge is happening while the motor is stationary while charging rather than powered while moving
That’s an interesting thought, perhaps the damage is from charging instead of driving?
That's a good call and sounds entirely plausible to me, arcing through the bearing whilst running causes a distinctive lined pattern on the bearing races, a bit like the patterns you get from the old Spirograph drawing toys. This isolated pitting looks like it's happened whilst stationary.
Yes please ! You could also maybe discuss with other electric specialists that manage ZOE repairs. Such as EVCLINIC in Croatia and RevoltClub in France !
What sort of cost are we looking at for replacing these with screened bearings? I am thinking maybe a preventative replacement at a time convenient to me rather than waiting until they are rumbling and having to have a car transported.
Hi it’s around £2k.
I previously needed to order / specify motors for use with industrial AC variable speed drives. For larger motors I would always tell the motor manufacturer that they will be used for this duty, they would supply insulated bearings / shaft brushes to overcome currents induced in the motor shaft by the inverter switching frequency. I suspect Renault use the same inverter technology as an industrial VS drive so should take account of these potential issues and I’m very surprised that they don’t. It is interesting that Nissan Leaf motors have shaft brushes and don’t seem to suffer from the same issues.
There should also be a common mode filter fitted between the inverter and motor.
I think my idea of buying a Zoe has ended. Your tales of woe have been most enlightening. Wonder if you've explored other EV mechanical problems? Your arcing theory is interesting. Could it also just be poor lubrication? I dread to think what the noise was like when this bearing was running.
You should lokk at the raceway in one of the better looking bearings. The key is finding the first signs of failure. The one you took apart is worn out much too far.
Iirc there was a period when satellites with gyroscopes were failing after solar flares, the investigation came to the same conclusion that a potential difference was causing arcing across the bearing, soon after they would seize.
Wow that’s interesting. 😀
I have already seen similar damage on wheel bearings: it came from static electricity which literally formed electric arcs
The new Renault EVs (Scenic, Megane, R4, R5 E-Tech) all have, to my knowledge, engines without permanent magnets. I wonder if Renault has rectified this or this can still be a problem.
Let’s hope it’s been rectified !
Take a look at the inner and outer races, if you see some fluting (lines perpendicular to the rotating motion) then this would be a sign of bearing currents.
Will do, thanks!
Would the mysterious spring on the brush end of the rotor shaft act to equilise the case and rotor potentials, or does it just contact the static outer race?
The large spring is just on the outer race so doesn’t connect
Possible no grounding of the rotor? So the current flows through the bearings and results in the pitting.
Yes indeed
Has the Dacia Spring got a different motor?
Let’s hope so
What are the prospects for the replacement bearing if arcing is the cause of the failure first time around? Surely not good?
I got bearings with metal shields to give another path for discharge. In any case if im fixing a car that’s done 100k miles then it’s likely the motor will outlast the car if it does another 100k! Cheers
Just thinking out loud here but are there any other common factors that you have noticed when dealing with these bearing failure cars other than the motor types. So for example the types of chargers i.e. Have the cars had a mix of charger types of are they mostly CCS or 40 kilowatt chargers.
I try to avoid bearings with cages when fixing my bike. Old bearings put in at the factory usually get the ball cages shredded over time which does nothing to improve rolling resistance or lubrication.
Really interesting
I don't believe discharging is the issue. There's easier ways for the rotor to ground out, through the output shaft for example. Those pits are classic for a bearing that's got too hot and has likely suffered false brinelling due to the affects of vibration. There's also something called rolling fatigue that occurs leading to fractures of the bearing surface, but that's usually more noticeable in the raceway than the balls.
I think it's probably more just a case that those bearings are too lightweight for what they're doing, and possibly that this design of motor is more inclined to produce vibration. Permanent magnet I believe runs smoother.
When you think about it it's actually amazing that these two little ball bearings last as long as they do given the speed of the rotor, and the fact they never receive any fresh lubrication or the cooling affect that would have if oil were pumped through the bearing as in an ICE.
Interesting thoughts, the motor does spin at around 10,500rpm at motorway speed.
+1. It seems to be a mechanical issue, not an electric one.
In one of the EVTV Motor Verks (m.youtube.com/@EVTVMotors) videos Jack Rickard was discussing the reseon behind metal brushes on Tesla Model S motor rotor shaft. And it was there for exactly the same arc discharge reason. Apparently early Model S motors had a tendency to granade themselves too due to the charge build up and eventual discharge via the bearings.
Here is the exact bit in the EVTV Motor Verks "Hacking the Tesla Drive Train" video where Jack Rickard starts discussing the metal bushes/bristles near the rotor bearings in Tesla Model Ss Induction motor stator's housing: ua-cam.com/video/_rqMT3-Tlls/v-deo.html
@@LAZASASRIP Jack 🙏🏼
What are the chances of adding a brush and slipring?
That would be pretty tricky tbh.
It's heat, they are uncooled.
Looks like the bearing inside my chinese made telescope mount. Can't believe how small and puny these bearings are for something that has to resist such high torque and rotational speed. Telescope weighs about 10kG and rotates a mere one revolution per day to keep up with the earth's motion.
Yes they are rather small !
Outside of any warranty issues....these cars are probably all out of warranty
Renault's fix is to replace the whole motor....It would be interesting to know if the replacement motors have a different design
Surely this should be something that Renault are forced to carry out a Recall and replacement on the specific motor types as the motor is not fit for purpose. Has this been raised with the regulatory authorities?
The car has a 3/4/5 year warranty dependent on age, if the car gets out of that it’s not their issue ! They will happily sell you a new car though!
@ but if it is an issue that can happen at any time- or if the vehicle were used as a taxi covering high mileage surely Renault would be liable for using a motor/bearing design that is not fit for purpose. Are you aware if anyone has raised the issue officially?
I heard of "hybrid bearings" where they use some ceramic material for the balls which will work as an isolator. Maybe that type of bearing would work better in these motors.
Interesting, I will have a look.
Would it not just move the problem to the gearbox?
@@frippefrippe5760 I don't know, but the current would have to pass a gear first in that case? Maybe the gears could be affected but will take a lot longer before becoming an issue compared to the ball bearings.
Have you any advice for Zoe owners on how to extend the life of the bearings? Does driving style make any difference or charging speeds?
My ZE50 has reached 93,000 miles without any problems with the motor bearings. 99% of my charging is overnight on a 7kW home charger and I tend to drive it efficiently avoiding harsh acceleration.
Does gentle driving and slower charging help, or is this wishful thinking?
Gentle driving yes. It will lower the current going through the bearing and also reduce wear on the bearing anyway. Charging doesn't matter but it will preserve battery health.
I wouldn't be so quick to exclude charging. The Zoe uses the windings in the motor as a transformer during charging, so while the car isnt moving there's still power in the motor windings. This is also why the Zoe is louder during charging.
@@mitchese1 Makes sense... I wonder which genius designed that system... but which moron forgot the arcing issues.....
Not sure on charging, need to think about that more but gentler driving definitely increases the life. Lower power Zoe’s seem to suffer less from the bearing issues.
@@khalidacosta7133 Actually I think it is a pretty genius thing to do: saves weight on the charger circuit, uses components already in the vehicle to reduce cost.
We have a 2015 zoe which has not had this issue (currently 135k km on it)
I am surprised at just how small these bearing are. Somebody cutting corners between design and production. I blame accountants.
Why is there rust on the outer race? To me it looks like a car wheel bearing- classic water damage.
If it's caused by eddy currents, you'd see the same pitting (more so) on the pinion gear teeth at the end of the shaft.
Think about car alternators- you'd get the same effect if it was eddy currents.
With it appearing to be only in one spot on each ball you have to ask - are the balls rolling or sliding ? If they are sliding there should be a continuous wear pattern around the surface of the race.
Arcs happen when the ball breaks contact with the race, so maybe once a spot wears, it arcs at that exact spot every time it rolls around.
@@robinbennett5994 Without more information on the wear pattern on the race it's all guesswork.
I suspected bearing currents long time. What i am curious is why some people replace motors multiple times. And some people can run really long on their motor. (Mine has gone 240000km for example on first motor, but the wifes r90 (identical) had motor changed at 50000km. Could it be that its the inverter that is the problem and not the motor? (the problem arrieses from the inverter not producing enough balanced 3 phase current, so it will not sum up 0v). That could explain the stories of people needing 2 motor swaps on the cars life (some inverters giving better 3 phase output than others)
That is interesting, need to work out how to test that !
Interesting point.
Maybe also production differences in rotor windings will matter?
I had my motor replaced on warranty after only 45000 km.
Wow that’s low!
That bearing had from for 50% more balls.
I wondered if different charging regimes would impact wear differently, granny charger vs 7kW vs 22 kW?
I assume the motor isn't used in CCS/DC charging?
Interesting thought as the motor stator windings are used during charging for boost conversion.
I'm not sure if it is used for boost conversion, but after all it's still some windings but it's not a transformer. I think it is used as a reactor/ballast and the higher voltage is achieved in the motor inverter
Phase Gate Control,
Of you rectify 230Vac, with a full brigde rectifier, you will get about 325Vdc, the rest can be done via phase gate Control in the inverter. At work our industrial converters produce 840Vdc from 600V input, you can step up this DCvoltage up to 1000V or even higher without changing the input
Using the cheapest bearings available !!
😁 Renault saving 5p on bearings? Surely not!
Looks like there's going to be a lot of failed 50Kwh Zoe's in the next 5 years when they start to get to the 100-125k miles range...
That’s quite possible! I’m fixing ze40s back to back at the moment !
When I was choosing my first EV it was between Zoe & Leaf! Glad I went Leaf after watching your videos. The Leaf is liquid cooled on charger/inverter & motor housing. Those Zoe bearings have been cooked to death by motor winding heat, common mode & parasitic currents & possibly corrosion. They look black, never seen bearings like that before. Is it burnt grease or the metal? You didn’t show us the bearing races. Do they have fluting or similar damage? I’m shocked at this bad design fault but fascinated by the causes. Thanks for showing this.
The BIG issue with the leaf is the battery: it's is not cooled AT ALL (no liquid, no air, nothing) and it overheats during usage.
People are reporting insane battery degradation after just a few years, we're talking 70% state of health or even lower after 5 years or less.
Both the Leaf and the Zoe are terrible cars that won't last long unfortunately.
@ Your right of course. Zoe has great battery cooling but poor motors. Leaf has good motors but poor battery.
Just for context though my Leaf has done 43,000 miles is 8 year old in March yet battery health is still 96% SOH. Secret is don’t let battery get hot! In the UK that’s rarely a problem & it’s only been charged using granny charger. ( 2 rapid charges). It serves me well & is great to drive.
Next car will defo have liquid cooled battery & CCS.
@@Lesjaye 96% SoH after 8 years and 43,000 miles is quite impressive!
How do you prevent the battery from getting hot though?
As far as I know, there's no real way to do that with longer trips.
Maybe your daily routine involves small trips?
@@nicnl255 Small trips 5 -10 miles daily, 30-40 miles once a week. It’s an early leaf with 30 kw ,3.1 kw ac charging which were deemed to be the worst for degradation. It’s a particularly good battery & I lucked out. If you do repeated high mileage & rapid charging it’s not the car for you.
I think the problem is that they are too small for the load they carry. The design of the motor needs rethinking. They will run hot and cool slow - which anneals the metal. This reduces the hardness. Once this happens the bearing starts to flat off in places and then once the surface has gone, the rest is much softer material and it pits totally.
Is it not more likely that these are just poor quality bearings and the surface hardening is failing? If it were electrical discharge through the bearing wouldn't it generate a more regular wear pattern?
I bet someone deep inside renault is aware of this, especially if motors can fail inside the w'tee period and its costing them money.
My desire for a ZE50 as a cheap second car is fading 😢
Excellent videos by the way 😊
I'd have expected the same pattern your describe from arcing during running, but someone has pointed out that the motor forms part of the charging circuit so arcing whilst stationary is a distinct possibility.
Tiny ball bearing, huge torke and RPM; here is the result. :/
Maybe I was too much confident about my assumption
I'm watching "Axial Flux Motors Explained: The Future of EV Powertrains?" from
Munro Live
At 3:52 it's about electric static charges and a part to preserve the bearings from them.