Without getting into a lengthy physics lecture, this process of reversing polarity produces heat (or wasted energy). This is known as hysteresis loss. And that helps explain why increasing the voltage into the motor will not necessarily increase the output. Instead, it can fight the resistance of magnetic materials to reverse polarity--and simply heat iron.
Do not coil excess cable of different types (i.e. motor power and feedback) together. An efficient transformer is formed at HF. Cable lengths should ideally be trimmed to fit the application. If excess cable cannot be trimmed, it should be laid in an ‘S’ or figure eight pattern.