What is this nonsense about 3HP on 110V 15A circuits?
It is a universal physical law that 1 HP is equal to 746 watts. Given heating loss, power factor and other inefficiencies, it is usually best to consider 1 HP is going to need 1000-1200 watts. A 110V 15A circuit can only deliver 1850 watts to a motor, so it cannot possibly be more than approximately 2 HP. Given rational efficiency factors, 1.5HP is more like it. Some equipment manufacturers (Sears in particular, most router manufacturers in general 😉 advertise a HP rating that is far in excess of what is possible. They are giving you a “stall horsepower” or similar. That means the power is measured when the motor is just about to stop turning because of the load. What they don’t mention is that if you kept it in that condition for more than a few seconds your motor will melt – the motor is drawing far more current than its continuous rating. When comparing motors, compare the continuous horsepower. This should be on the motor nameplate. If you can’t find that figure, check the ampera
