3. Basic technologies used

Mains-powered motors cannot be used on VAGs, as the energy comes from a battery whose DC voltage is much lower than that of the mains. Motors must therefore be designed for very low voltages: 24 V, 36 V or 48 V.

The most common are brushed DC motors:

• permanent magnet motor ;

• separately excited motor ;

• compound motor ;

• series excitation motor.

Vector motors are beginning to appear, but often with higher operating voltages of 72 V or 96 V. Rotary field motors offer advantages in terms of compactness and maintenance. The fact remains, however, that the range of motors on offer is still very limited.

Not all VAG movements are handled in the same way. Indeed,...