Ward Leonard drives 75 years of development

Although the Ward Leonard drive system is familiar to most engineers, its special features are not always appreciated. When the system was first introduced in America 75 years ago, it was the subject of fierce criticism, and its early development for mine-winding and rolling-mill drives owes much to pioneering activities in Europe. Modern methods enable faster responses to be achieved, but no drive has shown itself more suitable than the Ward Leonard scheme for the purpose for which it was invented.