@ Roelof

1) ok I did not know that, but find it’s not useful. I cannot even use the quote function as this uses links.

3) I know what KV means in connection with BLDC motors. I have also read that thread before my post here. In fact I have read a lot of threads and other websites, but a Dyno is not a break in tool. On a Dyno you will accelerate the engine for a short time to stop and measure the power output. I have no doubts that a BLDC Motor or any other set up works fine there. My concern is that a BLDC used as a generator in break in bench will not survive a longer time, but that is what you need when breaking in an engine.
And yes you are right I have to use the right resistors in order to be able to adjust the load and compensate the power, but there is still the generator where I have my doubts.