Also check quantity and condition of lubricant in gearbox, if present on your tool. Some old greases turn into a stiff gel that increases drag, and reduces lubrication at the same time. Also: make sure that you're getting full voltage at our outlet (under load, preferably); when I moved into this house, everything was 14-2 (#14 AWG, 2 wires, no ground) and a few 16-2, and anything on a longish run couldn't handle my larger motors. Radial arm saw could be run for 3 - 4 minutes before popping the safety cutout (thermal device, resettable). After I ran 12-2 W/G (2 wires, #12 AWG, with ground), I could run it for hours without a problem. Before I rewired, I couldn't even START my bench grinder in the barn unless I shut off the lights, walked to the grinder and started it, then back to turn lights on, and tried to work without loading the grinder much, or it would shut itself AND the lights down. Problem was made worse by the fact that this is the LAST house on the line from the power company; across the road to the east everything is fed from a different source. I once saw 86 volts on my "110" line!