Managing the reliability of variable speed drives

Variable speed drives (VSDs) play a major role in motor-driven systems. Not only do they run motors at the right speed to optimise energy use, they can also detect excessive motor temperatures and extreme load conditions, improving reliability. However, they can only make this contribution if they are themselves reliable. So, what causes failures in VSDs? Some 80-90 percent of failures are the result of excessive temperatures or unsuitable environmental conditions. These in turn can…