This is a huge range of Flender gearboxes. I think you're looking for this one:
Flender_summation_gear.pdf
Do you specifically need the Flender? There are other choices...
Ready to go: new summation gearbox for electric buses and mobile machines
That one is new so you won't find a salvage/surplus unit, but it seems likely that there are other brands.
The whole idea of a summation gearbox seems strange to me. It just allows the use of two smaller motors rather than one larger one... but electric motors scale up very well, so one larger motor is cheaper and more efficient than two smaller ones, and avoids the need for two inverters. I suppose it's just the easiest way to use available surplus motors that are not the right size.
Flender_summation_gear.pdf
Do you specifically need the Flender? There are other choices...
Ready to go: new summation gearbox for electric buses and mobile machines
That one is new so you won't find a salvage/surplus unit, but it seems likely that there are other brands.
The whole idea of a summation gearbox seems strange to me. It just allows the use of two smaller motors rather than one larger one... but electric motors scale up very well, so one larger motor is cheaper and more efficient than two smaller ones, and avoids the need for two inverters. I suppose it's just the easiest way to use available surplus motors that are not the right size.