Woodward Expands Digital Transfer Switch Control Line (source: Woodward)
Woodward has announced the release of the DTSC-50 digital transfer switch controller, designed for opentransitionautomatic transfer switch control where circuit breakers or latching contactors are used. The DTSC-50 expands Woodward’s ATS control line to the midrange transfer switch market, complementing the existing multifunctional DTSC-200 controller.
The DTSC-50 is intended for emergency standby applications with a single generator. When the unit 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 two-wire, or three-phase four-wire systems.
The DTSC-50 is flush mounted and features a six-digit, seven-segment LED display that shows voltage and requency values for each phase, as well as engine hours, maintenance hours and number of transfers. LEDs 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 company said. 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 DTSC-50 uses breaker position reply signals to interlock the breakers internally, eliminating the need for external relays, Woodward said. The controller can also be configured to ignore breaker replies if they are unavailable, for instance in retrofit applications.
Woodward’s alternative transferswitch controller for the higher-end ATS market is the DTSC-200. This controller can be configured for applications including utility-gen, gen-gen or utilityutility systems. Source transfer can be performed as open, delayed or closed transition, with in-phase monitoring (synch check) to ensure smooth transfer.
The closed transition overlap time can be limited to less than 100 ms, or extended indefinitely via a discrete input for paralleling and soft load/unload. Available custom features include transfer inhibit, preferred source selection, load shed and restore; elevator pre-signal and generator exerciser programs, are built in.
The DTSC-200 controller has a backlit graphical LCD interface that displays three-phase voltage and frequency, phase rotation, current, real and reactive power, I/O status and alarms. A line diagram with four LEDs displays source availability and breaker status. The DTSC-200 also has sealed soft-keys for manual operation and for passwordprotected access to its LogicsManager programming functions. The Logics- Manager uses Boolean operators and programmable timers to provide complex system control, eliminating the need for a separate PLC.
The onboard I/O set of 12 discrete inputs and nine discrete outputs can be expanded using Woodward IKD1 modules, giving as much as 16 additional inputs and outputs, all of which are programmable with LogicsManager. Programming the DTSC-200 can also be done with a PC using Woodward’s Toolkit freeware, which can also function as a remote monitoring tool. CANopen and Modbus RS-485 communication allow for remote control, annunciation and SCADA interface.
Both the DTSC-50 and DTSC-200 controls are UL and cUL listed. The DTSC-200 control is also CE marked .