Dave,
When you get your compressor, take a pic of the motor name plate and PM it to me, or post it here and I'll tell you what to get.
It would be best to install this device local to the motor installation, secondary to the branch circuit protection from your main breaker box.
There are much higher standards for industrial control systems than for residential systems. You should see how some of the Control FREAKS rig up their houses and property.
