Errrrrrr.... that’s what I posted above - April 2019. Does that count?
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Model 3 Motors on the Tesla Parts Catalog
- Thread starter EVMike3
- Start date
Errrrrrr.... that’s what I posted above - April 2019. Does that count?
AlanSubie4Life
Efficiency Obsessed Member
Sorry...it looks like yours is April 2019 though (?). (Not early - it's Q2.) That still leaves a gap from January 5th to March 31st, 2019. Other than in Europe, where it is obvious they were using 990 motors in AWD non-P from somewhere near the beginning of 2019.
I'll check if my paper work shows it, but the salesman at the Bellevue store showed me the Jan 4th build date on screen to confirm it was going to be a 2019 car. The sticker only shows 1/19.
EricUSC
Member
Tesla has info on the build date and even the time the car rolled off the factory for each car. You can call Tesla or walk into the store and speak with an owner advisor and they'll be able to pull up the info.
AlanSubie4Life
Efficiency Obsessed Member
I’m going to hazard a crazy guess here:
Normally they use 24 drive FETS (6poles X 4 FETs per pole). The 4 FETs are grouped together in a silkscreen box on the board, and I think they may have separate drive circuits (don’t know), but source and drain are connected in parallel presumably.
I’m going to guess they’ve gone to 18 drive FETs. (6 X 3). They depopulated one of the spots to save money.
That would give ~75% peak current rating. Note that 630/840 (mentioned above) is 75%. (Ratio 3/4)
Those are my thoughts for today. Now we just need that guy on Ingineerix to take apart one of these 990s to see if this is correct.
Urbancowboy
Member
Here's a question that I was thinking about last night. I'm not very savvy when it comes to all this electrical engineering stuff, so forgive the ignorance.
A P will get a big jump on an AWD from a 20mph roll, but they're about equal from 50-60mph and up.
From my uneducated perspective, it would seem like WOT has similar peak current requirements in both of those scenarios.
Based on your suspicion, a 25% reduction of peak current seems material and like it would cause a performance disparity between P and AWD at all speeds, not just from 0-60.
Educate me…
One minor correction: While the motor has 6 steps in terms of electrical commutation, it is 3 phase and the 24 FETs are set up as 3 half bridges with 4 FETs on the high size and 4 FETs on the low side.
I'd learn toward them with binning the FETs ahead of time or testing the inverters after assembly to find the more efficient ones to flag as higher power.
AlanSubie4Life
Efficiency Obsessed Member
Thanks for the correction. I did notice there were only three bus bars.
Do you know anything about the gate drive circuitry for these groups of 4 and how that is managed. I assume the gates are independently driven (kind of looked that way) but no idea.
I don’t really know much about the details of motor controllers and drive circuitry and how it is managed...
I don't know the particulars. Given the chip layout, it looks like they are driven in sub-groups. If the large chips are full bridge drivers (seems feasible based on pin count however pin spacing seems off for 400V), then each half bridge has it's own gate circuit. The drivers may only be for the high side, and the low side are switched slower via the discrete parts in the middle of the FET groups.
AlanSubie4Life
Efficiency Obsessed Member
This is a good point and the same thought has crossed my mind. Do keep in mind, however, that once you get to high speeds, you're significantly off the actual power peak. This (from what I've been told/understand) is due to back EMF and other non-idealities which limit motor power capability at high RPM - I won't pretend to speak about that with any knowledge.
If you compare the dyno plots and acceleration vs. time (not dyno) at very high speeds, yes the two vehicles converge in performance. But since there is a lot less power being put down at that point as compared to around 45-60mph, that means less power from the battery, so there is less current being drawn from the battery, too (the battery voltage is approximately constant).
In addition, we don't know how the power is distributed between front and rear motors as speed increases. The distribution may change (I have no idea).
But just looking at the dyno plot comparisons between AWD & P, there is a huge difference in the peak power (you can also look at velocity vs. time data people have published, and see that it's about 25% more power, because at around 45mph the 3P has about 25% higher acceleration (proportional to torque) than the 3D). And it's the peak power that matters for these currents.
I agree though it does creates some questions around this hypothesis. However, see above for speculation and documentation on inverter currents. There did seem to (maybe) be a 630A remanufactured unit available for a bit (it's hidden now).
Anyway those are my thoughts on that. They may not be 100% correct.
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Urbancowboy
Member
MrBadger
Badger out
Does anyone have any insight into the longevity of the motor/inverter assembly - I'm particularly thinking about the electrolytic(?) foil capacitors that appear to be in there. I'm looking at long term ownership so don't like to think that a car may be totalled by a single relatively cheap component failure.
Yah.
The inverter current limit sets the motor torque limit. As the motor speed increases, the back EMF voltage increases and the power into the motor increases. At some point the motor(s) reaches the maximum pack power. At that point, the motor current starts decreasing (if it was not already being reduces by software). So at higher speeds, the increased current limit does not directly impact performance.
Electrolytics come in high temp long life versions, so I would not be concerned about that. All cars (and most other electronics) have them.
Biggest factor is operating temp, and since Tesla has active cooling, things should last a long time.
WilliamG
Hinge Fanatic
AlanSubie4Life
Efficiency Obsessed Member
Possibly, but it won't help, as the power output is controlled by software. Also, given we have no idea what the differences are, it might also not work at all since the software may be expecting to be driving a particular type of inverter and it may not be compatible (there's no way to know right now since we don't know whether there are any differences).
M109Rider
Active Member
Since there is a very technical group on this thread, I have a drive unit question.
Does anyone know the source of the high pitch whine we hear sometimes. ?
This same whine is more pronounced when the battery is in the preconditioning mode heading to a Supercharger.
Just curious if this is from the motor itself, inverter, or some other part in the drive unit.
Does anyone know the source of the high pitch whine we hear sometimes. ?
This same whine is more pronounced when the battery is in the preconditioning mode heading to a Supercharger.
Just curious if this is from the motor itself, inverter, or some other part in the drive unit.
AlanSubie4Life
Efficiency Obsessed Member
My guess is that it's just acoustic noise from the magnetic fields vibrating the stator. I would imagine that minimizing these would be correlated (possibly not 100%) with good efficiency. For the preconditioning, they're presumably altering the field vectors to somehow produce lower efficiency, and it probably produces a bit more vibration as well.
That's extremely hand-wavy, but they have a lot of control over exactly how they excite the windings in these motors, and it does seem that they can produce a fair amount of excess heat with non-optimal waveforms. And those non-optimal waveforms probably produce some heat & noise & vibration.
