Pulse power rating of resistor depends on value?

[cupoftea]

Hi,
The AC03 resistor has the feature that its pulse power rating depends not on the length of time of the power pulse, but also on the resistor value.
Why is this.?
Surely its just a case of how hot it gets, and that depends on the Joules/time alone?

AC03 (top right of page 5 shows lower resistance values have better pulse power rating)

https://www.vishay.com/docs/28730/ac_ac-at_ac-ni.pdf

 

[dick_freebird]

Low value resistors likely have more film thickness so maybe more power-to-blow. Over some range for a given film thickness you can play with L/W but when either of those gets stupid small (also affecting close-in thermal mass of the current carrying material hence power-to-blow pulsed or steady state) you have to change film thickness or film composition to "recenter range" for higher or lower R groups of values @ physical footprint.

 

[FvM]

This are wirewound resistors. Lower resistance types are made of thicker wire and have higher heat capacity.