I have a blender which is rated to 300W; however I measured during certain stages of usage that the power draw jumped to around 600W.
How do appliance manufacturers calculate the type plate power rating that they put on the machine?
Is it average? Max possible peak (plus some buffer)?
Note: The condition that I used my blender was not an abnormal use case for a blender.
"... not abnormal ..."
Increased thickness of the product in the blender, will increase the amps & watts consumed by the motor.
If your product was thicker than the "Test Standard Product" then yes you will easily measure higher Watts.
I believe, the "Test Time" for a Blender is 30 seconds.
The "Measured Watts" should use the same product, the same test time, and the same averaging logic vs the "Rated Watts" rating.
Otherwise you cannot compare the two different Watts ratings to arrive at anything useful.
I believe that "Measured Watts" must be within +/-15% of the "Rated Watts".
It is a motor and a blender - The Rated Watts vs Actual Measure Watts will be different.
A typical Blender that I've seen states ...
3 Peak Horsepower on the box but the Watts on the Nameplate is equivalent to only 2 HP.
So, some kind of averaging is occurring.
I think, running a blender at 100% Peak Horsepower for too long, will cause the motor to over-heat and fail.