Description
DS3800HSQD1J1E Product Overview
The DS3800HSQD1J1E is a low-horsepower sequence board that resides in GE Mark IV turbine and EX2000 exciter control racks. It plugs into the 6BA06 Euro-card file and acts as a timing sequencer: it issues start/stop commands to the low-HP motor contactors, buffers the gate-drive pulses to the SCR/IGBT bridge, and isolates the 5 V CPU from the 480 V class power electronics. Because all copper traces are fully encapsulated in high-temperature epoxy, the board is treated as a line-replaceable module—any internal fault requires a complete card swap rather than component-level rework. The module is fully hot-swappable when the rack is powered down, and its C-ESS assembly marking indicates it is qualified for essential-service applications.
The DS3800HSQD1J1E is a low-horsepower sequence board that resides in GE Mark IV turbine and EX2000 exciter control racks. It plugs into the 6BA06 Euro-card file and acts as a timing sequencer: it issues start/stop commands to the low-HP motor contactors, buffers the gate-drive pulses to the SCR/IGBT bridge, and isolates the 5 V CPU from the 480 V class power electronics. Because all copper traces are fully encapsulated in high-temperature epoxy, the board is treated as a line-replaceable module—any internal fault requires a complete card swap rather than component-level rework. The module is fully hot-swappable when the rack is powered down, and its C-ESS assembly marking indicates it is qualified for essential-service applications.
DS3800NRFA1F1E
DS3800HSQD1J1E Technical Specifications
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Model Number: DS3800HSQD1J1E
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Manufacturer: General Electric
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Product Type: Low-HP Sequence / Auxiliary Control Board
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Series: DS3800, Mark IV Speedtronic
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Form Factor: 6BA06 Euro-card (≈ 233 × 160 mm)
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Back-Plane Connector: Dual 40-pin header (J1/J2)
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Logic Levels: 5 V CMOS/TTL; 6-layer PCB for controlled impedance
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Isolation: 1500 Vdc channel-to-ground; opto-coupled digital lines
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Power Demand: +5 V @ 0.8 A, +15 V @ 0.2 A from rack 2PL bus
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Operating Temperature: 0 – 60 °C (board rating)
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Weight: ≈ 0.22 kg
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Construction: Epoxy-sealed copper traces—non-repairable
Core Features & Customer Value
Low-HP Sequencing Logic: The on-board state machine executes start/stop timing for motors ≤ 500 HP, ensuring contactors pick up in the correct order and the bridge is not fired into an open motor contact. For the operator this prevents nuisance “PHASE LOSS” trips and extends contactor life by eliminating simultaneous energization.
Epoxy-Sealed Construction: All internal copper is encapsulated in high-temperature epoxy. In environments with high humidity, dust, or conductive contamination the seal prevents trace-to-trace shorting that would otherwise cause random “SEQ FAIL” alarms after ten-plus years of service. The trade-off is non-repairability—any internal fault requires a whole-card exchange—but this is offset by the reduced troubleshooting time and the fact that plants stock one spare instead of maintaining a repair bench.
Plug-and-Play Euro-Card Footprint: The 6BA06 form-factor slides straight into the existing Mark IV card file—no mounting brackets, jumpers, or external cabling required. For maintenance crews this translates to a three-minute replacement instead of a half-shift re-cabling job.
Typical Applications
In combined-cycle power plants the board is installed in the Mark IV turbine control core where it provides the start/stop sequencing for the 480 V auxiliary cooling-fan motors. The on-board opto-isolators keep 480 V switching transients from walking into the 5 V CPU data bus.
On utility-scale EX2000 static exciters the same card is used to sequence the brushless-exciter cooling pumps. Because the inputs are group-isolated, a shorted pump contactor coil will not drag down the entire digital I/O rack.
Frequently the same part number is used on mechanical-drive gas compressors to sequence the lube-oil pumps and inlet-guide-vane actuators. Its ability to mix dry contacts and analog millivolt signals on one card makes it a universal “low-HP starter” for any Mark IV loop that needs deterministic, contactor-level control.
