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Beavis
Model S Signature 991
I interpreted this response as that they've identified a part with a higher than desired rate of failure, but the rate of failure in any one car, like yours, is still very small. I expect that they'll replace them anyway the next time they service your car, unless you specifically prohibit it. That would be consistent with their usual behavior.
I'm taking this update as an excuse to drive to their new service center (only two hours each way), and visit the area, where I had lived until about 15 years ago. I've also got a new punchlist for them to review.
strider
Active Member
Must have been the mentioned training issue or there is something different w/ Sig packs. We have an "A" pack on our car and our local SC (Burlingame) was able to do the work in-house.
Beavis
Model S Signature 991
They are doing my pack at the Service Center. I think it depends on the SC as to whether have have to send it to Fremont or not.
paco3791
TMC OG
Just got my car back from service. Took it in to have a headlight replaced (for free, thanks Tesla!) and they said they would be doing the switch/contactor replacement at the same time.
SeminoleFSU
Voluntaryist
It's funny. When they replaced mine, they didn't ask me to keep the SoC low. All part swaps were done at the Decatur, Ga location. My Tech told me he's one of only two techs certified to work on the HV pack in this manner. He said it is very expensive and time consuming to send the packs back to the factory from the east coast so they are starting to train their more senior techs on how to do this at their respective SC's. I too and very happy they did this proactively instead of allowing it to fail. Seems strange to me they don't know which parts were used without opening up the pack to take a look. Sounds like they need to work on tracking inventory and part usage to specific VINs a little better in the future. That way they would know for sure if the parts need to be replaced without having to open it up. Perhaps they already do and are just saying they might not have to replace it to make it sound less severe?
Beavis
Model S Signature 991
My tech told me that they are doing it at the Denver location to fix what they are planning to fix. He said there is a slight chance they have to send it to Fremont, depending upon what they find when they open it.
They probably have more than one part source for the same part #, have determined that X manuacturer's is subpar, but can't tell until they open up the pack which one was installed. GM had the same problem with their ignition switches. They also used the same part number for the redesigned part and then discovered they couldn't tell from the repair invoices who got a replacement with the good part, and who got the bad. So everyone who had a replacement had to be included in the recall, along with those that never had a repair. I imagine it gets very difficult to track the parts sources down to the individual parts in complicated assemblies.
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I wonder what is different with those packs, such that they need special training to open and fix?
Inside a contactor
There were pictures of the pack contactors from wk057's pack disassembly, the positive and negative have different part numbers and they have a very low contact resistance rating. It may be that they are testing the contact rating to determine if they are healthy or need to be replaced. To test them you can measure the voltage across the two termninal with a voltmeter set to the mV scale and plug the terminal to a lab power supply or any regulated current and voltage source. Set to 1V or less and with a couple of amps measure the mV reading, divide the mV by the supply current and you will get the resistance of the contact. Seems like spec was about 100 micro-Ohms.
Here's an inside view of the contacts, there is a magnet (missing here) in the side pocket to quench the arc and pull it away from the contact surface. It probably wouldn't survive many arcing events and still be able to meet spec, and they are not bi-directional for quenching.
There were pictures of the pack contactors from wk057's pack disassembly, the positive and negative have different part numbers and they have a very low contact resistance rating. It may be that they are testing the contact rating to determine if they are healthy or need to be replaced. To test them you can measure the voltage across the two termninal with a voltmeter set to the mV scale and plug the terminal to a lab power supply or any regulated current and voltage source. Set to 1V or less and with a couple of amps measure the mV reading, divide the mV by the supply current and you will get the resistance of the contact. Seems like spec was about 100 micro-Ohms.
Here's an inside view of the contacts, there is a magnet (missing here) in the side pocket to quench the arc and pull it away from the contact surface. It probably wouldn't survive many arcing events and still be able to meet spec, and they are not bi-directional for quenching.
Attachments
EarlyAdopter
Active Member
Interesting. What does it mean to "quench the arc" and how does a magnet affect that?
Also, and idea why the copper bar only extends to cover half of each copper disc?
Also, and idea why the copper bar only extends to cover half of each copper disc?
When the contactor circuit is closed and current is flowing thru the copper bar, then there will be a magnetic field generated by the inductance of the bar (right hand rule, thumb in direction of current, fingers are circles of field lines). The field is sustained by and proportional to the current.
If the circuit is interrupted while the current is flowing then this circular magnetic field is no longer sustained and will collapse. According to Michael Faraday's law of induction the collapsing field will generate a very high voltage in the bar to induce a current in the same direction as the original flow path. This very high voltage is what creates a fireball flash-over arc as the current is trying to compete the circuit--it has got to go somewhere, and if you don't control it, it will find whatever path it can. As a side note in air the voltage of static electricity is about 4,500 volts to jump a 0.1 inch gap.
So to extinguish or quench this arc such that nothing catches on fire and without damage to the low-resistance contact surface, a permanent magnet is placed such that its field is perpendicular to the plane of the contact button and crossing thru the side of the gap. Now when the arc occurs the electrons are deflected out of the gap from the end of the bar into the unused portion of the button according to a path described by the Lorentz Force.
If the circuit is interrupted while the current is flowing then this circular magnetic field is no longer sustained and will collapse. According to Michael Faraday's law of induction the collapsing field will generate a very high voltage in the bar to induce a current in the same direction as the original flow path. This very high voltage is what creates a fireball flash-over arc as the current is trying to compete the circuit--it has got to go somewhere, and if you don't control it, it will find whatever path it can. As a side note in air the voltage of static electricity is about 4,500 volts to jump a 0.1 inch gap.
So to extinguish or quench this arc such that nothing catches on fire and without damage to the low-resistance contact surface, a permanent magnet is placed such that its field is perpendicular to the plane of the contact button and crossing thru the side of the gap. Now when the arc occurs the electrons are deflected out of the gap from the end of the bar into the unused portion of the button according to a path described by the Lorentz Force.
lolachampcar
Well-Known Member
ChadS
Last tank of gas: March 2009
I just got a call today. My pack made it to headquarters, and after examining it they decided it would be simpler to let me keep the "temporary" pack rather than rebuild mine, ship it back up here, and swap it.
Not sure what was wrong with the old pack (it worked beautifully, and we had over 40k miles) or what will happen to it. But I was told the replacement pack has never been used before - though it is another A-rev pack. But hey, that's cool - a brand-new pack even though I never had any problems with the original. I think Tesla is serious about avoiding problems.
(edit: clarify they didn't say the new pack had just been built; only that it hadn't been used)
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Had my service done yesterday (S3 PACK CNTCTR,SRVC FIELD KIT 1 (1042673-S3-B)) at the Rocklin SvC. Seemed pretty routine. IIRC I have a "b" pack.
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