[QUOTE=safe;8381946]High voltage is a way to overcome the downside of motors that are naturally of higher resistance.

The DC resistance of motors typically has only a small effect on efficiency or power, sometimes insignificant. A good motor will have much, much higher reactance. I would not necessarily call higher resistance a downside. It is just one component of an engineering tradeoff.

Increasing voltage does two things: First, it increases the top speed of a motor, which is limited by back EMF and has a theoretical maximum of the motor's Kv constant times voltage. Second, it forces more current through the windings at any given speed, producing more power.

Reducing resistance requires thicker or shorter wire, which typically means fewer turns, less reactance, and the need for more current to generate the same magnetic field, negating the benefit of lowering the resistance.

Alternatively, one can reason that high resistance motors will generally have more turns of thinner wire, allowing them to operate with less current than low resistance variants. The lower current in effect cancels out the higher resistance, resulting in no difference in efficiency. The higher turn motor will, of course, require higher voltage to force the current to flow, but power (voltage times current) will stay the same.