Description
Application Scenarios
A 12-storey mixed-use building in a region with frequent utility brownouts had been using a conventional electromechanical ATS relay that transferred solely on undervoltage. During one sustained sag event, the relay opened the utility breaker while the generator was still cranking, then re-transferred back as the utility momentarily recovered — repeating the cycle four times before the load finally settled. After replacing the relay with the DTSC-200-55B, the controller’s independently adjustable outage timer, stable timer and in-phase monitor prevented any transfer until the utility source had genuinely failed and the generator was synchronised. The site’s facilities manager reported that subsequent outages produced a single clean transfer with no re-cycling, and that the elevator pre-signal and motor-load-disconnect timers had eliminated the nuisance stoppages that previously followed each power disturbance.
The value of the DTSC-200-55B in this type of installation is that it treats a transfer as a managed event rather than a binary reaction. Brownouts, phase loss, voltage unbalance and frequency excursions are evaluated against configurable fail and restore limits and independent timer channels, so a brief sag does not throw a critical load onto a genset that is not yet ready, and a recovering utility is not accepted back until it is stable. That distinction is what prevents the equipment-damaging and occupant-disrupting transfer chatter that simpler controls allow.
Parameter
| Parameter | Value / Description |
|---|---|
| Product Model | DTSC-200-55B |
| Order Part Number | 8440-1868 |
| Manufacturer | Woodward |
| Product Category | Automatic Transfer Switch (ATS) Controller / Digital Transfer Switch Control |
| Auxiliary Supply | 12/24 Vdc, 6.5–40.0 Vdc (not buffered) — runs from standard control-bus or station battery supply |
| Power Consumption | Max. 8 W; 3 W in power-save mode (backlight and relays off) |
| Inrush Current | Max. 50 A peak, 1 ms |
| Input Capacitance | 2000 μF |
| Source Voltage Sensing | 3-phase/4-wire, true-RMS; 120 Vac nominal (max. 150 Vac) or 480 Vac nominal (max. 600 Vac), separately selectable for Source 1 and Source 2 |
| Load Current Sensing | 3-phase/4-wire, true-RMS; 5 A CT input (standard) or 1 A CT input (optional) |
| Transition Modes | Open (break-before-make), delayed (timed neutral position) and closed (make-before-break) |
| Synch Check | ANSI 25 in-phase monitoring — phase-angle difference ≤ 7° before transfer |
| Closed-Transition Overlap | < 100 ms momentary, extendable indefinitely via discrete input for paralleling |
| Discrete Inputs | 12, freely configurable through LogicsManager |
| Discrete Outputs | 9, freely configurable through LogicsManager |
| Communication | Galvanically isolated CANopen; RS-485 Modbus RTU Slave (full-duplex and half-duplex) |
| Protection Functions | ANSI 59/27, 81O/81U, 47, phase rotation, 32, 50/51, switch plausibility, transfer failure, battery, parallel-time monitoring |
| Display | Graphic LCD with sealed soft-keys (DynamicsLCD) plus line diagram and four high-intensity status LEDs |
| Event Recorder | 300 FIFO entries with real-time clock and battery backup |
| Timers | Neutral delay, elevator pre-signal, motor-load disconnect, stable and outage timers; 1–6500 s ranges with 0.1–10.0 s outage resolution |
| Mounting | Flush-mounting, screw or clamp fastening |
| Cutout Dimensions | 186 × 138 mm |
| Overall Dimensions | 219 × 171 × 61 mm (approx. 8.6 × 6.7 × 2.4 in) |
| Weight | Approx. 0.8 kg |
| Listings and Approvals | UL Listed, cUL Listed, CE Marked, GOST-R |
| Configuration | Woodward ToolKit software via PC; settings files compatible with the DTSC-200 family |
