According to Dave Martindale :
Mark Lloyd writes:

Lowe's claims to have a 3HP electric chain saw, that still works on a
15A receptacle.

Assuming it's not simply a baldfaced lie, that is an intermittent
rating. As in "if you load this motor with a brake to the point where
it produces maximum output in overload, it's producing 3 HP - until the
circuit breaker trips or the motor burns up, whichever comes first".

Yes. It's an instantaneous max HP, rather than a safe continuous
rating. Shop vacuums and routers are infamous for using these inflated
figures. Instantaneous max HP is a useful measure on a router or
chain saw in some cases, but is useless to a shop vacuum.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.