Why more current?

[myndseye]

When we discuss big motors like the 1521's and up by Neu, why is it that we figure that they require more amps? Is it just because they are physically bigger? You would think that a similarly rated (kv) motor, on a larger scale should need less amperage to do the same work as a smaller can motor. Ten amps through the windings creates a field of larger magnitude in the larger motor, correct? That should create more electromotive force to overcome the load, right? Should not the smaller motor need more current (at same voltage) to build a field large enough to get the same amount of power out?

Some smarter people than me , please chime in here and set me straight if I'm wrong.