Running LDU in reverse

[P.S.Mangelsdorf]

Is there any reason, assuming the oil pump is addressed, that a LDU cannot or should not be run backwards? i.e. reverse to go forwards and forwards to reverse? What about in a performance application?

If I can put one backwards it may be the solution to my packaging problem (what I get for trying to use a formerly live axle car with a LDU and IRS) which has had me stalled for a while.

[tom91]

No issues, in the mercedes B-Class they run in reverse all the time.

Having reviewed the gearing and bearings there is no problem, if you do indeed sort out the oil pump.

[Boxster EV]

Is there any reason, assuming the oil pump is addressed, that a LDU cannot or should not be run backwards? i.e. reverse to go forwards and forwards to reverse? What about in a performance application?

If I can put one backwards it may be the solution to my packaging problem (what I get for trying to use a formerly live axle car with a LDU and IRS) which has had me stalled for a while.

In reverse IIRC:

[P.S.Mangelsdorf]

In reverse IIRC:

Awesome! Is that with a LSD?

[tom91]

In reverse IIRC:

Awesome! Is that with a LSD?

I do not know if it had it fitted in that exact video. But yes that car now has an LSD.

Most lighter applications the open diff cannot keep up with the torque transfer anyway and usually both wheels will spin.

[leman2112]

Let me know if you want to buy my mercedes b class tesla large drive unit. 3200 bucks plus shipping. It's on ebay.

[leman2112]

or possibly trade. just damian is sold out of logic boards right now. I bought a bare board. maybe polykups VCU will work? I sent him an email. just ordered a bare board however, I have no idea if I will ever get it going because of my electrical skills...

[P.S.Mangelsdorf]

or possibly trade. just damian is sold out of logic boards right now. I bought a bare board. maybe polykups VCU will work? I sent him an email. just ordered a bare board however, I have no idea if I will ever get it going because of my electrical skills...

Right now I have enough time to wait for Damien's new boards.

I also modeled the LDU mounted reverse and it still won't clear the suspension I was going to use. I've already started on a Plan B with it mounted in the normal configuration, which is probably what I'll stick with.

[leman2112]

oh sweet! glad damian might be building some more boards!!! that is some bad ass news!! guess I got time now too....

[P.S.Mangelsdorf]

oh sweet! glad damian might be building some more boards!!! that is some bad ass news!! guess I got time now too....

[Roadstercycle]

Ok, a new reverse question. In reverse does the cruise control work the same? Since the motor is running in reverse is there any limitations on RPM? (I'm not referring to the oil pump limit)

Also since in my new application the motor will be disconnected from the gearing and run direct drive would it be better to switch 2 legs of the 3 phase to the motor so the motor will run backwards when in forward thus the controller working normally as intended? That's how we switch 3 phase motors in the shop if they are running backwards or does it not make any difference to the controller at all?

[arber333]

Ok, a new reverse question. In reverse does the cruise control work the same? Since the motor is running in reverse is there any limitations on RPM? (I'm not referring to the oil pump limit)

Also since in my new application the motor will be disconnected from the gearing and run direct drive would it be better to switch 2 legs of the 3 phase to the motor so the motor will run backwards when in forward thus the controller working normally as intended? That's how we switch 3 phase motors in the shop if they are running backwards or does it not make any difference to the controller at all?

Resolver will know motor is turning the wrong way. I imagine this would show a fault in its brain.
Maybe you should also switch sin cos wire outputs .

[Jack Bauer]

Ok, a new reverse question. In reverse does the cruise control work the same? Since the motor is running in reverse is there any limitations on RPM? (I'm not referring to the oil pump limit)

Also since in my new application the motor will be disconnected from the gearing and run direct drive would it be better to switch 2 legs of the 3 phase to the motor so the motor will run backwards when in forward thus the controller working normally as intended? That's how we switch 3 phase motors in the shop if they are running backwards or does it not make any difference to the controller at all?

No need to do any of that. There are no limits in the inverter firmware. It does not care if you are running in forward or reverse unlike the stock Tesla logic.

[Roadstercycle]

Awesome, Thank you Damien.

[ViktorT]

Great info.I suppose it is the same for the SDU?

[P.S.Mangelsdorf]

Great info.I suppose it is the same for the SDU?

Given that they run on the same basic firmware, I assume the answer is yes, provided you deal with any lubrication issues

There are no limits in the inverter firmware.