Russ; I would find someone with a clamp on amp probe and see what the motor is pulling on start up. I bet it will be north of 30-40 amps or more. If your motor doesn't reach full speed in a second or two, it will pop the breaker. Take the impeller off the motor shaft and take another reading. If it still pops the breaker, you may have dry or bad bearings if it hasn't been used in a while. Most modern motors have sealed bearings, so you can't lube them. You could run a 30 amp breaker if you use #10 wire, or you could wire the motor for 220 volts if it allows you to do so. Usualy a 1.5 hp motor will be made to run both voltages. There should be a diagram on the motor plate that tells you how to connect the wires for both voltages. On a 120V motor you should have a black, white, and a green wire for your leads. On a 220V motor you should have a black and red for your leads and maybe a green to ground the motor back to the box. Make sure the motor turns freely by hand with no drag or bearing noise. Also check for a bent shaft. I run a 120V 1.5 hp motor on a 20 amp breaker on my main vac system. If I don't use it for a while, or I start it when the shop is cold, it may trip the breaher several times before it will keep running. Same with my contractor table saw. Also if your motor is a capacitor start, that may be bad. Jim S
