I made a new acquisition that I can't find a lot of information about. It seems like it's a 1970s 28 Volt, DC, 17.9 Amp, 500W generator powered by a 1 cylinder, two stroke, gas engine, with a rip-cord pull start (not recoil!). This seems very similar to the US Department of Defense MEP-024A, but you can see from the diagrams it's slightly different. Searching for all variations of the part numbers on the label has yielded surprisingly little. YouTube video has found some videos of similar, but not identical, rigs.
Since this only puts out 28 VDC @ 17.9 AMPS (0.5 KW), and from what related equipment I found with it's NSN, I'm pretty sure this rig would have been used to power auxiliary equipment like signals / communications gear. I believe it would be called a "tactical" generator set, as it's portable.