Vintage industrial Simplex electric rotary knife cloth cutter. This is for cutting heavy fabric and textiles such as denim and canvas (or multiple layers) as well as leather, upholstery vinyl etc..
It has a built in grinding stone for sharpening the cutting blade in place and a work light for illuminating the cutter path for accurate cutting.
It is a Simplex KE series (either model 4 or 5, we're not sure which as we didn't see the marking).
This is from the liquidation of a custom upholstery business and includes an extra blade and the original paperwork with parts list and bill of sale from the early 1940s.
We've plugged this in and it runs well. This is in nery vice vintage condition but does have some light rust to the steel blades and a small nick to the long power cord that could probably be patched with some black electrical tape.