Sensing & Controls News

Digital Transfer Switch Control

Woodward has announced the release of the DTSC-50 digital transfer switch controller, designed for open-transition automatic transfer switch control where circuit breakers or latching contactors are used. The DTSC-50 expands Woodward’s ATS control line to the mid-range transfer switch market, complementing the existing multi-functional DTSC-200 controller.

Intended for emergency stand-by applications with a single generator, when the DTSC-50  detects a utility failure, it commands the generator to start and transfers the load to the emergency source. When utility power is restored, it performs an open-transition return transfer and allows the engine to cool-down before stopping. It can be used in single-phase 2-wire, or three-phase 4-wire systems.

The DTSC-50 is flush-mounted and features a 6-digit, 7-segment LED display that shows voltage and frequency values for each phase, as well as engine hours, maintenance hours and number of transfers. LED’s annunciate active alarms and show breaker status and source availability. Sealed soft-keys enable the user to start the generator and operate the transfer switch manually.

Password-protected programming can be accomplished through the front face or with a PC. The unit is fully enclosed in a plastic housing for safety and has removable terminal blocks for easy wiring. Parameter limits and timers for utility and generator monitoring are freely programmable, adding a level of flexibility in the DTSC-50. Protections in the DTSC-50 include utility and generator over/under voltage (59/27), over/under frequency (81 O/U), phase rotation, breaker fail to open/close, engine fail to start and engine unintended stop.

The system uses breaker position reply signals to interlock the breakers internally, eliminating the need for external relays. The controller can also be configured to ignore breaker replies if they are unavailable, for instance in retrofit applications.