In Chapter 3 we proved that PBC of mechanical systems reduces, in regulation tasks with full state feedback, to the classical PD controller used in most robotic applications. Furthermore, when velocities are not available for measurement the PBC methodology suggests to replace the velocities by their approximate derivatives, which is also a standard procedure in applications. This "downward compatibility" of PBC with current engineering practice is a remarkable feature whose importance can hardly be overestimated. On one hand, it provides a solid system-theoretic foundation to popular control strategies which enhances their understanding and paves the way for subsequent improvements. On the other hand, viewing the new controllers as "upgrades" of the existing ones, it facilitates the transfer of these developments to practitioners. In this chapter we will show that, under some simplifying assumptions on the machine model, the PBC for electrical machines presented in previous chapters also has a "downward compatibility" property with the industry standard field-oriented controller (FOC).