Description
DS3800DSWA1A1A: Product Overview
The DS3800DSWA1A1A is a daughterboard-level switch/sequencer that plugs onto a motherboard carrier inside the Mark IV rack. It routes and sequences 24 V DC dry-contact signals that energise/de-energise starter motors, ignition transformers, fuel-solenoid valves, and indicator lamps during the automated start-up, acceleration, and shutdown sequences of Frame 5/6/7/9 gas turbines. The card is hardware-configured (no firmware) and deterministic, making it suitable for safety-related interlocking when paired with the main CPU.
Physical implementation is a 3 in × 5 in daughterboard with 12 precision trimmers (contact wetting, pull-in delay, drop-out delay) and 12 gold-pinned jumpers that select switching modes (momentary, latching, interlocked). 20-pin ribbon carries coil drive and contact feedback to/from the carrier motherboard; 1500 V AC opto-isolation breaks ground loops between turbine deck and control room. Front-edge LEDs (red/green) per channel give real-time contact status—no multimeter required during commissioning.
Environmental qualification meets IEEE 344 Class 1 (seismic) and –40 °C to +85 °C operation, permitting installation directly on the turbine deck with no extra HVAC. MTBF is >250 000 h at 55 °C, giving >20-year service life in peaking or baseload duty.
DS3800DSWA1A1A: Technical Specifications
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Model Number: DS3800DSWA1A1A
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Manufacturer: General Electric (GE Energy)
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Product Type: Switch / Sequencer Auxiliary Daughterboard
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Function: Dry-contact routing, step sequencing, interlocking logic
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Switching Channels: 8 SPDT form-C relays (24 V DC coil, 2 A resistive)
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Input Control: 24 V DC logic levels from CPU or I/O card
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Isolation: 1500 V AC coil-to-contact, 500 V channel-to-channel
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Contact Life: 100 000 operations at 2 A, 24 V DC
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Trimmers: 12 (pull-in delay, drop-out delay, contact wetting)
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Jumpers: 12 (momentary, latching, interlocked, coil polarity)
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Connectors: 20-pin ribbon, keyed, gold-plated
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Power Rails: +24 V DC coil, +5 V DC logic, <0.5 W per channel
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LEDs: Green = contact closed, Red = coil fault / open circuit
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Temp Range: -40 °C to +85 °C operational, -55 °C to +125 °C storage
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Vibration / Shock: 15 g continuous, 30 g shock (IEEE 344)
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Certifications: SIL2 (IEC 61508), API 670, CE industrial emissions
DS3800DSWA1A1A
Core Features & Customer Value
Deterministic Step Sequencing for Safe Start-Up
Relay logic executes starter-motor engagement, ignition-on, fuel-valve open, and acceleration-hold in exact order—no firmware, no scan jitter. <5 ms contact-to-contact skew meets API 670 sequencing requirements, preventing false start or crank-hang.
Relay logic executes starter-motor engagement, ignition-on, fuel-valve open, and acceleration-hold in exact order—no firmware, no scan jitter. <5 ms contact-to-contact skew meets API 670 sequencing requirements, preventing false start or crank-hang.
Hot-Swappable in TMR Strings
Redundant Mark IV allows online replacement of one sequencer card; remaining two legs continue voting. MTTR is <5 min—no outage, no load shed, no restart required.
Redundant Mark IV allows online replacement of one sequencer card; remaining two legs continue voting. MTTR is <5 min—no outage, no load shed, no restart required.
Field-Adjustable Without Software
Trimmer pots compensate for contact erosion, cable voltage drop, or coil aging—technician can lengthen pull-in delay or increase wetting voltage using only a screwdriver and a DMM, reducing dependency on OEM support.
Trimmer pots compensate for contact erosion, cable voltage drop, or coil aging—technician can lengthen pull-in delay or increase wetting voltage using only a screwdriver and a DMM, reducing dependency on OEM support.
Surge-Hardened for Turbine Deck
TVS diodes and opto-isolators clamp >500 V spikes from starter solenoids or lightning. 1500 V isolation prevents ground-fault propagation to CPU cards, reducing cascade failures by >60 % compared with non-isolated relay cards.
TVS diodes and opto-isolators clamp >500 V spikes from starter solenoids or lightning. 1500 V isolation prevents ground-fault propagation to CPU cards, reducing cascade failures by >60 % compared with non-isolated relay cards.
Typical Applications
Gas Turbine Start-Up Sequence
Controls starter-motor contactor, ignition transformer, pilot solenoid, and main fuel valve in strict order during Frame 7/9 auto-start. Interlock logic prevents fuel admission until crank-speed >15 % and ignition confirmed.
Controls starter-motor contactor, ignition transformer, pilot solenoid, and main fuel valve in strict order during Frame 7/9 auto-start. Interlock logic prevents fuel admission until crank-speed >15 % and ignition confirmed.
Steam Turbine Turning-Gear & Auxiliaries
Sequences turning-gear motor, lube-oil pump, and jacking-oil solenoid during coast-down and restart. Latching mode keeps lube pump running without continuous coil heating, extending relay life to >100 k cycles.
Sequences turning-gear motor, lube-oil pump, and jacking-oil solenoid during coast-down and restart. Latching mode keeps lube pump running without continuous coil heating, extending relay life to >100 k cycles.
Black-Start Diesel & Emergency Systems
Drives emergency lube pump, battery charger contactor, and breaker close coil during island-mode black-start. Fail-safe de-energise logic defaults to safe state on loss of 24 V, meeting IEC 61508 SIL2 requirements.
Drives emergency lube pump, battery charger contactor, and breaker close coil during island-mode black-start. Fail-safe de-energise logic defaults to safe state on loss of 24 V, meeting IEC 61508 SIL2 requirements.
