And this is why this 'continuous power rating' is utter nonsense and meaningless.
A 250w continuous rating means that the motor will run at that rating continuously (normally taken to be 30 minutes +)without overheating.
So all that could be done is to input a precise 6.94A (250w at 36v) and see that the motor does not overheat !
But batteries are hardly ever at 36v.
Is this input or output power?
It says nothing about peak power.
A motor will run at what is put into it. The higher the voltage the greater the rpm. The higher the current the higher the torque. Of course, eventually, you will arrive at the point of burning out the windings.
So, do they test to destruction to find the power of a motor?
And so we get dozens of people coming on this forum wrapped up in big numbers, 1k motors etc. When all they need is a legally rated motor but with a control syatem tuned to what they want it to do and, complying to assisted speed limit, they will be perfectly legal.