Saturday, April 10, 2021




 

electric car

Explanation No. 6 in this lesson,right part number but it's   it's very similar uh i uh this information is at pyroswitch.com you can go look at the different   pyro switches that are made by auto leave but anyway I thought it was very interesting i   totally disassembled this yesterday and then put it back together as you can see in these   photos .

New console top performance:

it has a little circuit board it has a shunt circuit a parallel current circuit   uh where it appears to be watching the amount of current going through the pyro switch so this is a   pyroswitch made by auto leave there's a circuit monitoring the current going through it and   once the current going through it reaches some predetermined level I don't know what that is   uh on the press release for the p90d it said 1500 amps but the P100D is even more powerful so it   it probably has a higher rating but as soon as it gets to whatever rating tesla has decided   it's going to cap it at then it'll apply a voltage and it gives a a certain voltage to   fire it's 1.75 amps for half a millisecond and then it physically breaks open this high   voltage DC circuit and of course there'll be an arc flash at that high current   but it has a little area to contain the arc flash and anyway it's an impressive   impressive little unit I understand there's one for the Model 3 and the model y uh also okay so these what that means why should you care about the pyrofuse or a fuse is that   any of these cables here any of these high voltage cables   if you were to get in an automobile accident and pinch any of these cables to the vehicle chassis   pinching just one of them won't do anything other than trigger trouble codes for   something called loss of isolation and i have different uh training videos on those   but if both of them get pinched through to the chassis or if they get pinched to each other   then that creates a short circuit and rather than creating a short circuit that could cause   say a fire they open the circuit very quickly this opens within 0.5 milliseconds 500 microseconds   so that is to try to prevent fires from starting from high voltage circuits   and possibly from fuses that don't open at a predictable time okay well let's follow the   the cables now to the front of the vehicle and see what they connect to okay I'm on   a different workbench now to assemble and connect all of the high voltage components   from a tesla model s that are in the front of the vehicle on the second generation   tesla model s so i have the positive and negative cables that are coming from that   rapid splitter assembly on the other table here and I want you to see it's a little over 12   and a half feet long but the cables go all the way over to the other workbench where we were before   12 and a half feet which is approximately 3.84 meters of high voltage shielded cable so where does this go up front it goes to what's called a high power   distribution block or module so there are the two cables coming in from the front of the vehicle   right here and then we have two cables going out to the front Drive Unit front electric motor   and then a bunch of other cables going.

High voltage shielded cables:

to other high voltage components   on the front of the vehicle so I have two of these high voltage junction blocks   uh let's look inside of the other one I use this one for my actual connections but here is   the other one I don't have it all labeled but i have removed the bolts and have taken the cover   off of it and i want you to see that inside of here we have four fuses going across the top here   there are two 40 amp fuses these two great big ones right there in the middle   and then there's a 30 amp fuse right there and another 30 amp fuse on this side   so all four of these outputs right here are fused now the cable coming from the front of the vehicle   going through is just a straight shot to the front motor the pyro fuse that we talked about protects   that circuit but there are fuses in this high voltage distribution block or junction block and   this is really hidden away on the vehicle I can't even see it it's above the battery underneath the   underneath the vehicle, you would have to remove the battery to even get to this so it's not   something that you're just going to be able to do easily this does have right here a little button   switch it's an interlock , We move to the explanation number 7 of this lesson.