That is part of a later generation Convergent NGEN system... sort of a modular multi-user workstation. Here is a picture of what a complete one would look like... of course that's an early model, but the later ones used a similar sort of chassis design.

The power supply is proprietary, and I don't know if you can easily adapt a standard one to work... even if you were able to trace out the pins, I believe they also use some non-standard voltages.

You are also missing the RAM cards, which look like something like this. Again, proprietary.

Basically, getting it going will be difficult at best. If you're intent on it, you could try posting about it over at the Vintage Computer Forum... somebody there might have some of the relevant parts or some more detailed information about it.