By Monica Cintron, Astrodyne TDI
Astrodyne TDI designs and manufactures custom power distribution units (PDUs) to support a wide range of applications, including the medical, semiconductor capital equipment, and industrial markets.
The primary function of a PDU is the distribution of reliable, controlled electric power to various system elements. A well-designed PDU can provide a variety of safety features and power conditioning, as well as output monitoring and controls. A common form of output control is sequential turn on. The sequential application of power at precise times allows for proper system function as well as limiting potential inrush currents.
Typical PDU configurations include circuit breakers, auxiliary power converters, main power distribution, EMI filtering, and a built-in remote interface for remote connectivity. Of course, all applications and system requirements are unique; connections and capabilities often vary.
Custom PDUs offer efficient implementation of a variety of safety features, such as ground fault interruption (GFI), emergency machine off (EMO), system interlocks, and welded relay protection. A common safety feature, GFI circuitry prevents equipment damage by opening the main circuit breaker should any ground faults be detected.
Likewise, many PDU units include an EMO feature, where the system can be quickly powered off through initiation with either a local push-button control or via an external input signal. Interlock circuits are set up to assure all critical equipment is present and properly connected before system power can be applied.
Monitoring circuits can also protect against welded relay conditions. A welded relay occurs when the relay remains closed after being de-energized, preventing the unit from shutting down properly. If a welded relay condition is detected the main circuit breaker immediately removes power from the high current outputs.