STN Atlas GMM10 Generator Management Module (GMM 10)

Product Information

Manufacturer	STN Atlas Marine Electronics (STN ATLAS Elektronik, Germany)
Model	GMM10 (GMM 10)
Product Type	Generator Management Module – generator protection, synchronizing and load sharing unit
Display message (photo)	GMMBUS-open
Part Number	Not clearly visible in the supplied photograph
Serial Number	Not clearly visible in the supplied photograph
Housing	19-inch rack-mount subrack with plug-in modules
Country of Manufacture	Not clearly visible in the supplied photograph
Condition	Refurbished
Supplier	SM MARINE SERVICE™, Chattogram, Bangladesh

Product Introduction

The STN Atlas GMM10 Generator Management Module is the electronic heart of many ship power management systems. It monitors and protects a ship's diesel or shaft generator, synchronizes it to the main switchboard bus bar and shares the load with the other generators. SM MARINE SERVICE™ (https://www.smmarineservice.com/) supplies the GMM10 and its plug-in cards in refurbished condition to ship owners, ship managers, shipyards and electrical service companies worldwide.

What Is This Equipment?

According to the STN Atlas description (document 271.123 221.BGE), the GMM 10 is an electronic module for monitoring three-phase ship's mains supplies. One GMM10 is installed for each generator in the main switchboard. All GMM10 units are linked in a ring by the serial GMM-Bus for active load sharing, blackout connection interlocks, mains and load monitoring. A GEAPAS-Bus (RS485) connects the units to a higher-level diesel monitoring or data-logging system. The front panel has an LED dot-matrix display, parameter and display keys, P1/P2, TEST and QUIT keys, a parameter LED, an alarm LED and K1–K4 relay indicator lamps.

Main Features

• Generator protection: undervoltage, overvoltage, over/underfrequency, short circuit, overcurrent, reverse power, phase asymmetry, stator protection and excitation monitoring
• Differential protection and earth-fault protection (generator and mains)
• Automatic synchronizing of the generator circuit breaker
• Sliding frequency regulation and active load sharing between generators
• Mains monitoring with automatic blackout start and connection
• Load monitoring and preferential tripping of non-essential loads (stage 1 / 2 / 3)
• Undervoltage coil energizing, with USS402 support system
• GMM-Bus ring between all GMM10 units and GEAPAS-Bus (RS485) interface
• Front panel LED display with parameter, test and alarm functions; parameters stored in EEPROM

STN Atlas GMM10 Generator Management Module – supplied by SM MARINE SERVICE™

Main Technical Specifications

Model	GMM10 / GMM 10
Function	Generator protection, synchronizing, load sharing, mains and load monitoring
Module supply	3 x 24 V, 0.6 A from transformer secondary (X6:2,3,4); max. 35 V
Battery backup (option)	24 V automation battery, max. 1.5 A, 6.3 A fuse (X6:5–8)
Undervoltage coil supply	3 x 150 V, 0.1 A (X17) for 220 V / 20 W coil
Communication	GMM-Bus serial ring (X2:1–5); GEAPAS-Bus RS485 (X1)
Relay indicators	K1–K4 on two plug-in modules (alarm, load shedding, breaker, watchdog)
Operator keys	Parameter − / +, Display ↓ / ↑, P1, P2, TEST, QUIT
Display	Red LED dot-matrix text display
Mounting	19-inch rack subrack in main switchboard
Documentation	271.123 221.BGE (description), 271.123 221.TDE (parameter list)

Inside the Unit: PCBs, Modules & Part Numbers

The cards below are named in the STN Atlas GMM 10 description and in GMM10 module listings. The exact set of cards depends on the ship's configuration. Card part numbers (271.xxx.xxx) for each board were not found in a public source unless shown.

ZKG404 – Central Card

Central card of the GMM10, carrying the RAM and the GMM-Bus / GEAPAS-Bus termination resistors. Its front panel (ZKG-403 panel) shows relay lamps K1–K4: unimportant loads stage 2, collective alarm, unimportant loads stage 1 and watchdog.

SWK401 / SWK403 – Transformer Module

Transformer module for voltage, current and earth-fault signals. Its front panel shows K1–K4: undervoltage coil, circuit-breaker tensioning, circuit-breaker fault and breaker switch-on signal.

BAT404 – Operating / Display Panel

Front display and keypad module of the GMM10 (listed in GMM10 module sets). BAT 406 / BAT407 are remote display and control units.

SLE401 – Serial / Parallel Interface Card

Interface cards at positions A1 and A69 (SPI bus).

USS402 – Undervoltage Coil Support System

Keeps the breaker undervoltage coil energized during short-circuit trip delays.

MEG437 / NEG437 – Power Supply

Power supply module (MEG437 listed in GMM10 module sets; NEG437 referenced as the power supply fuse in the manual). Exact designation: Not verified.

GDS401 – Analogue Differential Protection Board

Optional analogue differential-protection PC board.

GDE404 – Digital Differential Protection Board

Optional digital differential-protection PC board.

SWK402 – Earth-Fault Transformer Module

Transformer module for earth-fault signals.

DEA401 – Additional Relay Board

Additional relay outputs DA5–DA8.

EDR401 – Electronic Diesel Controller Card

Electronic speed/diesel control card (see document 271.132 244.BGE).

ZDM401 – Load Monitoring Extension

Digital extension for load monitoring.

Related GMM 10 Versions

GMM 10.18 (part no. 271.123.403) and GMM 10.18A (part no. 271.151 435) are listed by spare parts sellers as STN Atlas generator management modules. Whether this unit is one of these versions: Not verified.

Main Components & Related Units

• GMM10 – one per generator in the main switchboard
• DMU 10 – Diesel control module
• BAT 406 / BAT407 – Remote display and control units
• EDR401 – Electronic diesel controller (governor) card
• USS402 – Undervoltage coil support system
• GEAPAS diesel monitoring / data logging system (via RS485)
• Related STN Atlas / Lyngsø Marine automation modules such as SIM 401, MXM 402, DSM401

Marine & Industrial Applications

• Ship power management systems (PMS) in the main switchboard
• Diesel generator and shaft generator protection and synchronizing
• Container ships, tankers, bulk carriers, ferries and offshore vessels
• Blackout recovery and automatic generator start / connection
• Preferential tripping of non-essential consumers

STN Atlas GMM10 front panel with LED display, keys and K1–K4 relay indicators

Common Problems & Troubleshooting

• Display shows "GMMBus open": the GMM-Bus ring is interrupted – check bus cables, connectors and termination (normal when the unit is tested alone on a bench).
• Breaker will not close / synchronizing timeout: check voltage and frequency signals, governor control and the breaker circuit.
• Unequal load sharing: check governor (EDR) response, GMM-Bus communication and load sharing parameters.
• "EEPROM error" or "Failure ±15V": check the power supply and the central card.
• Power fuse alarm: check the 24 V supply and fuses.
• Breaker trips on reverse power or overcurrent: check the engine, load and protection settings.

Safety note: the GMM10 is connected to live switchboard voltage and current transformers. Isolate the generator and short CT circuits before work; only qualified marine electricians should change cards or parameters. Parameter changes are protected by a code and saved to EEPROM.

Common Alarms

Display alarm texts documented in the STN Atlas GMM 10 description include: Overcurrent 1, Overcurrent 2, Reverse power, Overvoltage, Undervoltage, Overfrequency, Underfrequency, Short circ 1, Short circ 2, Phase failure, Phase asymm, Stator prot., Exciter f., Earth fault, Gen earth fault, I difference, CB fault, T-sync>max, Blackout-CBO, GMMBus open, GMMBus reception, EEPROM error, Failure ± 15V, Power fuse, ZDM bus fault, DMU bus fault, GovernMotErr, DG trouble, SG trouble, Uniload st 1/2/3.

Maintenance Tips

• Keep the switchboard clean, dry and well ventilated
• Check GMM-Bus cables, connectors and plug-in card seating
• Record all parameters before replacing a card or unit
• Test protection, synchronizing and blackout functions during class surveys
• Keep a spare GMM10 or critical cards on board

Spare Parts & Replacement Availability

SM MARINE SERVICE™ supplies the STN Atlas GMM10 complete unit and its plug-in cards. For a quotation, please send the vessel name, photos of the unit front and the card labels (part number 271.xxx.xxx), the software/version if known, and the quantity. We ship worldwide.

Why This Equipment Is Still Used

Many ships built with STN Atlas power management systems are still in service. Replacing a GMM10 or one of its cards with the same model keeps the switchboard wiring, bus communication and class approval unchanged, and is much cheaper than a new power management system.

FAQ

What is the STN Atlas GMM10?
A Generator Management Module that protects, synchronizes and load-shares a ship's generator.

What does "GMMBUS-open" on the display mean?
It is a documented message showing the GMM-Bus ring is open, for example when the unit is not connected to the other GMM10 units.

Which PCBs are inside the GMM10?
Cards named for the GMM10 include ZKG404, SWK401/SWK403, BAT404, SLE401, USS402 and MEG437, with options GDS401, GDE404, SWK402, DEA401, EDR401 and ZDM401.

What is ZKG404?
The central card of the GMM10 with RAM and bus termination.

What is SLE401?
A serial/parallel interface card used in the GMM10.

What is USS402?
The undervoltage coil support system.

What are GMM 10.18 and GMM 10.18A?
Versions listed with part numbers 271.123.403 and 271.151 435 by spare parts sellers.

What do K1–K4 lamps show?
Relay states such as collective alarm, load shedding stages, watchdog and circuit-breaker signals.

Can you supply a single card?
Yes, please send the card label photo for checking.

Is this unit refurbished?
Yes, it is offered in refurbished condition.

Do you ship worldwide?
Yes, SM MARINE SERVICE™ ships worldwide.

Short Product Description

The STN Atlas GMM10 is a Generator Management Module used in ship power management systems. Installed in the main switchboard, one unit per generator, it provides generator protection (over/under voltage and frequency, overcurrent, short circuit, reverse power, earth fault), automatic synchronizing, active load sharing, blackout recovery and preferential tripping. Units are linked by the GMM-Bus ring and to diesel monitoring by the GEAPAS RS485 bus. Plug-in cards include ZKG404, SWK401/403, BAT404, SLE401, USS402 and MEG437. SM MARINE SERVICE™ supplies the GMM10 and its cards in refurbished condition, with worldwide shipping from Bangladesh and China.

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SM MARINE SERVICE™ – Marine Automation & Navigation Equipment Supplier

Available Equipment Conditions: New • Used • Refurbished • Reconditioned (Specific product condition and availability are subject to confirmation.)

Stock Locations: Bangladesh • China

Services: Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing

Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh

Mobile / WhatsApp / Viber: +88 01818 929292

Email: info@smmarineservice.com

Website: https://www.smmarineservice.com/

Contact SM MARINE SERVICE™ today for a quotation on the STN Atlas GMM10 Generator Management Module and its cards.

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