Description
DS3800NMSM1G1E Product Overview
The DS3800NMSM1G1E is a switch-mode DC/DC power-supply regulator used inside GE Mark IV Speedtronic turbine and compressor control cubicles. It occupies a standard 6U card slot on the Mark IV control backplane and converts the raw 125 VDC station battery into the low-voltage rails required by the microprocessor, memory, and analog I/O cards.
The DS3800NMSM1G1E is a switch-mode DC/DC power-supply regulator used inside GE Mark IV Speedtronic turbine and compressor control cubicles. It occupies a standard 6U card slot on the Mark IV control backplane and converts the raw 125 VDC station battery into the low-voltage rails required by the microprocessor, memory, and analog I/O cards.
In the automation hierarchy the board sits at the “power-distribution” layer: it receives bulk DC from the battery distribution panel, performs galvanic isolation, and delivers tightly-regulated 5 V (±5 %), ±12 V (±2 %), and 28 V auxiliary outputs. A current-fold-back circuit protects the card and downstream loads from shorts, while a front-panel green LED gives local confirmation that all rails are within tolerance.
The card is part of the DS3800 “N” family of Mark IV personality boards—cards that share the same mechanical envelope and edge-connector pattern but perform dedicated functions. Using a common hardware platform allows plant stores to stock one spare chassis and populate it with the exact personality boards required for each drive section.
GE DS3800NMSM1G1E
Technical Specifications
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Model Number: DS3800NMSM1G1E
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Manufacturer: General Electric
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Product Type: Switch-Mode Power-Supply (DC/DC Converter) Board
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Input Voltage: 125 VDC nominal (90 … 140 VDC operating)
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Output Rails: 5 VDC @ 6 A (logic), ±12 VDC @ 1 A (analog), 28 VDC @ 3 A (auxiliary)
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Isolation: Transformer-coupled, basic insulation between battery and low-voltage sides
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Protection: Current-fold-back short-circuit protection, over-temperature shutdown
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Status Indication: Front-panel green “POWER GOOD” LED
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Connectors: 96-pin DIN edge finger (backplane), no external field terminals
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Mounting: Standard Mark IV card rails, captive screws
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Weight: ≈ 0.25 kg (0.55 lb)
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Operating Temperature: 0 … +70 °C (card ambient)
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Storage Temperature: -40 … +85 °C
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Vibration/Shock: 5 g / 50 g (per Mark IV cabinet spec)
Core Features & Customer Value
Integrated multi-rail supply – One card delivers all three voltages required by the Mark IV control set (5 V logic, ±12 V analog, 28 V aux), eliminating separate DC/DC bricks and their associated wiring and heat.
Integrated multi-rail supply – One card delivers all three voltages required by the Mark IV control set (5 V logic, ±12 V analog, 28 V aux), eliminating separate DC/DC bricks and their associated wiring and heat.
Current-fold-back protection – If a downstream card shorts, the converter folds current back to ~200 mA instead of crow-barring, so the fault is localized and the backplane remains powered. This prevents the classic “one short kills the whole rack” scenario.
Transformer isolation – Basic insulation between the 125 VDC battery and the low-voltage rails means ground-shift events (common when 4 kV breakers close) do not propagate into the microprocessor logic, improving uptime and reducing nuisance faults.
Front-panel power-good LED – Local visual confirmation that all rails are in spec; during commissioning you can spot a failing supply immediately without metering each rail at the backplane.
Drop-in spare – Shares the same DS3800 form factor as earlier NMSM revisions; no mounting changes, no parameter downloads, and no calibration required during swap-out.
GE DS3800NMSM1G1E
Typical Applications
In combined-cycle plants the DS3800NMSM1G1E is installed in the “control power” bay of every Mark IV panel that governs gas turbines, boiler-feed pumps, or induced-draft fans. It powers the microprocessor, memory, and analog I/O cards while riding out battery transients during breaker closures.
In combined-cycle plants the DS3800NMSM1G1E is installed in the “control power” bay of every Mark IV panel that governs gas turbines, boiler-feed pumps, or induced-draft fans. It powers the microprocessor, memory, and analog I/O cards while riding out battery transients during breaker closures.
In pipeline compressor stations the same board feeds the Mark IV speed controller that drives 10 MW gas-engine centrifugal compressors; the 28 V auxiliary rail energizes the overspeed trip solenoid, so loss of the power-supply card forces an automatic shutdown.
Because the card is passive (no firmware) it is also accepted in nuclear standby turbine-generator sets, where “simple device” classification avoids additional software V&V.
