Engineering is a small world lol, crazy that the MoneroMining reddit got a shoutout for info on operating PSUs.

When I was young, I saw the aftermath of the speed sensor belt breaking on a 1000HP dynamometer. I think the DUT was an EV engine, the damage was quite impressive. The controller capacitors had blown, the output shaft was broken, the torque sensor had a 250Nm offset, the rotor had contacted the stator and destroyed the coils.

Very cool, I thought about this when testing regenerative braking parameters on the electric cars I put together.

I ended up just spinning the motor with a hand drill and later fine tuning in an empty car park.

Your solution is much better to get engine hours and a proper load on your test piece in a lab environment!