If the source of supply is d.c. (for example in a battery vehicle or a rapid transit system) a chopper-type converter is usually employed. The basic operation of a single-switch chopper was discussed ...

The thyristor d.c. drive remains an important speed-controlled industrial drive, especially where the higher maintenance cost associated with the d.c. motor brushes (c.f. induction motor) is tolerable ...

The first type of motor built is still in widespread use In the late 1800s, several inventors built the first working motors, which used direct current (DC) power. After the invention of the induction ...