A transformer switching onto a line can sometimes cause a circuit breaker to trip or a fuse to blow. This phenomenon occurs even if the transformer presents no load, such as when the secondary is open ...

Acceptable ohm reading for a good current relay. One type of starting relay used on fractional-horsepower compressors is the current relay. This type of starting relay uses the initial high inrush ...

This Design Idea shows how to use a 63¢ (Q=1) microprocessor reset voltage detector IC in a relay coil drive circuit to greatly reduce the coil’s hold-in current. When asked to estimate the coil ...

This month in EC&M's forum for your power quality questions, Mark McGranaghan, vice president of consulting services, teams up with several other experts from EPRI-PEAC to address the topics of ...

If used correctly, a reed relay is a superbly reliable device. The switch contacts are hermetically sealed, so they don’t suffer from oxidization or contamination in the same way as an open ...