[TimPa]

if problem exists in a "no load" condition, that is blade is on but no cutting action, as you mentioned, and on a dedicated 20a circuit (verify all of this), the problem is likely the motor/power transmission system. direct drive? belts/pulleys/bearings ok? has it had any harsh environment? check out the run capacitor/centrifugal switch if there is one.

electrical circuit of saw is definitely in question if it is tripping a 20a ckt bkr