Took this photo from the engine of an industrial vacuum. The power rating says 58 kw, but the device can't possibly generate that much power. What is the proper way of reading these?
You read it as 58 KW at 3,100 RPM – that's about 78 HP.
The engine code is a bit hard to read, it looks to me to be either an AFD or AFO, doing a bit of searching I found Club VeeDub's list of engine codes. They show the AFD code was used for a 1.9 liter turbocharged diesel industrial engine rated at 60 KW (80 HP, the list says 90, but the math doesn't work out, I assume it's a typo). There is no entry for the AFO code.
I then searched on AFD and found Specifications for Volkswagen Industrial Engine (AFD) which has output curves in it. The curve shows a power output of pretty close to 58 KW at 3,100 RPM. According to the specs there are two ECU codings available as stock, this engine appears to be coding 02.
I also found a technical brief, 1,9 ltr-TDI-Industrial Engine, which appears to be for the same engine, although it doesn't explicitly mention any engine code.