Question about appliance power rating and bursts

[gary_feesher]

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.

 

[summitville]

Average Watts under typical use.
Usually not Peak Watts unless the name plate specifically states "PEAK".
Many motors have a rating called "Stall Amps" which is significantly higher than average running amps.

 

[gary_feesher]

Based on the IEC test report description, and the appended table; does this mean that the "P Measured" is the average wattage during the typical use?

Or is the P Measured the maximum power draw measured during the course of the use of the product?

 

[schmitt trigger]

The paragraphs in the second row tell you exactly what requires to be done.

The keywords here are representative operation period. This operation requires to be well defined.

Think of it to something similar to the Miles per gallon (or liters per 100 Km) that a vehicle manufacturer quotes. It is actually a combination cycle consisting of start/stop with idle similar to city driving, and highway speeds. If certain power-robbing accessories are included in the vehicle, like air conditioning, those must be also included.

Watching how my wife operates a blender, I would say that the rated power should be consumption while loaded, i.e. actually churning a cake batter. The blenders are so noisy that she immediately stops it after churning. The no-load power occurs only during a minuscule fraction of the work period.

 

[summitville]

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.