Jeff Wisnia wrote:

... there really isn't any difference between a "run" and a "start"
capacitor, the term comes from the application, not the design.

I seem to recall that start caps are smaller and less expensive and rated
for less ripple current than run caps. For instance, Grainger's 4CU61 and
2GU30 caps have similar values and voltage ratings, but the 4CU61 costs
$8.26 vs $15.12, and it's only rated for 20 3-second starts per hour, ie
a 2% vs 100% duty cycle.

Nick