A variable frequency drive (VFD) fails to vary the discharge-air fan speed. A motor overheats and fails prematurely. Programmable controls that generally operate without issue suddenly experience ...

This chapter covers representative general-purpose relays used in the control circuits of most industrial, commercial, and consumer products. Relay names and terminology are in accordance with ...

Relays and contactors use a variety of technologies to switch signals and power connections. Many devices called relays use similar techniques and topologies, but the terminology can be confusing.

This AC Power Monitor continuously watches the AC power line voltage for both under-voltage and missing cycles. When it detects a total of 5 or 6 consecutive missing half-cycles (50mS, 50/60HZ), it ...

When designing equipment with switching functions, most engineers find that switching high currents and high voltages is a major problem. A solid-state solution may be possible, but it’s complex and ...