Steven,
I know you are not arguing and it is better to ask and find out.
The motor is still AC even although it uses brushes. If it was DC the motor wouldn't turn.
My coment about load was the physical resistance operating against the router bit, which is the physical resistance of the wood being cut.
This causes an electrical loading upon the motor.
The best way to explain this is to try an experiment. Using an electrical drill turn the chuck slowly by hand, it will move with little physical resistance. The chuck is connected (via a clutch and gearing) to the drill rotor, the central bit of the motor, that spins within stator or the cage of the motor. On a brush motor the stator has big magnets.
As it turns slowly the magnets induce an electrical current (as an AC waveform, i.e. positive to negative) within the windings of the rotor but not enough to notice. If you turn the chuck fast by hand you will notice resistance, this is the electrical current genrated within the rotor windings increasing enough to cause an electrical resisitance, that is the AC waveform going from positive to negative is strong enough to cause an opposing force against the magnets.
So when the power is on, the AC waveform causes the rotor windings to change polarity from positive to negative 50 times per second (electro magnetic force, EMF, some people say electro motive force), this then causes attraction and opposition to the polarity of the magnets making the rotor spin.
With no physical load against the movement of rotation the rotor will happily spin and not actually draw or consume much power. When the resistance against the bit increases the motor requires more power to maintain its speed of rotation as it has to increase the EMF of the rotor.
As the power increases then other characteristics change within the motor, mainly heat. As the windings get hotter the resistance changes effecting the current which changes the power that can be sustained under load. So each device has a maximum sustainable power rating before the windings overheat and melt.
The ability of the motor to continue is speed of rotation under load is torque, so a very well designed and constructed motor could produce more torque at a lower power rating than an inferior quality motor. (back to the original question, is 1300W PC maybe more torquey than 1800W Makita).
An induction motor uses an AC waveform in both the rotor and stator, so there are no magnets just copper windings. The polarity of the winding of the stator is always the same as that of the winding of the rotor directly opposite it. So we know that the opposite of poles attract, so a + + charge or - - charge would make the rotor and stator try and physically seperate themselves, causing the rotor to spin.
As the EMF of the windings can produce a greater magnetic force than a solid magnet induction motors tend to be more powerfull, but as there is more windings they are physically bigger and need more ventialtion to keep them cool.
Depending on how the motors are wound can also effect the power of the motor; if the rotor and stator are in series with each other there is more power and torque, as in a car starter motor.
Unfortunately if there is no physical load on the motor the speed will be very high and likely cause the motor to self destruct. That is why you should never conect a car starter motor to a power supply without first having some form of mechanical resistance on the motor shaft, cause it can blow up !!!
The other way is to have the rotor and stator wired in parallel with each other, like a table saw motor. This is less torquey but offers far more speed control.
I hope this descrition is understandable, if i knew how to draw pictures I could describe it better. :?
Matstro, if you have read this far and not got bored then I am looking forward to hearing about your exploits in returning the Porter Cable.
