Description
Key Technical Specifications
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Model Number: DS3800NPSE1E1G
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Manufacturer: General Electric
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Function: Power-supply sequencing, regulation, and fault monitoring for field supplies
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Output Rails: +24 Vdc contactor bus, ±15 Vdc gate drive, +5 Vdc logic
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Construction: 6BA08 Euro-card form-factor; epoxy-sealed copper traces (non-repairable)
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Connectors: High-density pin headers for field buses; 40-pin back-plane to CPU rack
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Isolation: 1500 Vdc input-to-logic; opto-isolated status lines
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Operating Temperature: 0 – 60 °C board rating
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Power Demand: Draws housekeeping voltages from rack 2PL bus; distributes up to 6 A combined field rails
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Status Feedback: On-board comparator chain reports under/over-voltage to CPU via NDIA bus
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Weight: ≈ 1.2 kg metal-clad frame
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Repairability: Component-level replacement not recommended—board swap only
DS3800NPSE1E1G
Field Application & Problem Solved
In a Mark IV exciter the field supply needs three clean rails to come up in sequence so the SCRs don’t fire into an un-powered SDCC. This card is the sequencer. It sits between the control transformer and the back-plane, ramps the rails in the correct order, and kills the whole stack if any rail collapses. When a lightning hit blows the on-board varistor, the epoxy seal keeps the fault from spreading—you swap the whole card in three minutes and the turbine is back to VAR control—no download, no re-cal. Every EX2000 cabinet keeps a spare taped inside the door because without NPSE you have no field power; no field, no megawatts.
In a Mark IV exciter the field supply needs three clean rails to come up in sequence so the SCRs don’t fire into an un-powered SDCC. This card is the sequencer. It sits between the control transformer and the back-plane, ramps the rails in the correct order, and kills the whole stack if any rail collapses. When a lightning hit blows the on-board varistor, the epoxy seal keeps the fault from spreading—you swap the whole card in three minutes and the turbine is back to VAR control—no download, no re-cal. Every EX2000 cabinet keeps a spare taped inside the door because without NPSE you have no field power; no field, no megawatts.
Installation & Maintenance Pitfalls (Expert Tips)
Epoxy seal means no trace repair
If a via lifts or a copper plane burns, you cannot solder it—epoxy won’t take heat. Order a new board; attempting repair voids the UL listing and you’ll fight the same fault next month
Epoxy seal means no trace repair
If a via lifts or a copper plane burns, you cannot solder it—epoxy won’t take heat. Order a new board; attempting repair voids the UL listing and you’ll fight the same fault next month
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High-density connectors must seat evenly
The 40-pin back-plane header is long—half-latch one side and you get random “POWER FAULT” that clears when you wiggle the card. Push until both extractors click, then tug-test.
The 40-pin back-plane header is long—half-latch one side and you get random “POWER FAULT” that clears when you wiggle the card. Push until both extractors click, then tug-test.
Power-up sequence is hard-wired
The card enforces rail sequencing in hardware. If you rack it after the CPU is already booted, the CPU throws “NPSE TIMEOUT” and hangs. Always install in slot order: power, I/O, then CPU.
The card enforces rail sequencing in hardware. If you rack it after the CPU is already booted, the CPU throws “NPSE TIMEOUT” and hangs. Always install in slot order: power, I/O, then CPU.
Field fuse sizing is board-specific
Factory ships with fuses sized for the field rheostat. If you upgrade the motor HP and forget to change the fuse, a fault will vaporize the copper trace inside the epoxy and you’re buying a whole new board. Verify the job drawing before you close the breaker.
Factory ships with fuses sized for the field rheostat. If you upgrade the motor HP and forget to change the fuse, a fault will vaporize the copper trace inside the epoxy and you’re buying a whole new board. Verify the job drawing before you close the breaker.
DS3800NPSE1E1G
Technical Deep Dive & Overview
Internally the card is a passive power highway with on-board comparators. Linear regulators generate ±15 V from the 24 V field bus; a crow-bar SCR protects the 5 V rail; opto-couplers report “POWER GOOD” to the NDIA data bus. Because everything is hardware, you can hot-swap with the rack powered: pull the old card, slam in the new, seat the 40-pin connector, and the CPU re-acquires “POWER OK” inside 100 ms
Internally the card is a passive power highway with on-board comparators. Linear regulators generate ±15 V from the 24 V field bus; a crow-bar SCR protects the 5 V rail; opto-couplers report “POWER GOOD” to the NDIA data bus. Because everything is hardware, you can hot-swap with the rack powered: pull the old card, slam in the new, seat the 40-pin connector, and the CPU re-acquires “POWER OK” inside 100 ms
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