The enabling of adjustable speed drives for motors by using insulated-gate bipolar transistors (IGBTs) is discussed. Pulse width modulation waveforms are described. Power losses in IGBTs are evaluated. Factory automation systems using complementary IGBTs for numerical controls are described. The IGBT circuits for robotics, welding machines, induction heating units, and milling/drilling machines are provided. The use of IGBT drives for metals processing, paper mills, and textile mills is discussed. Its use in mining/excavation and electrostatic precipitators is described.