ABB Synpol D CMA 120 3DDE 300 400 Generator Controller

The ABB Synpol D CMA 120 (MPN: 3DDE 300 400) is a dedicated microcomputer-based basic controller panel and parameter monitor engineered for marine electrical distribution switchboards, offshore installations, and demanding industrial power plants. Designed specifically for generator protection, automatic synchronizing, digital governor/AVR regulation, load sharing, and complete Power Management System (PMS) operations, the CMA 120 acts as the primary user interface and processing unit within the modular Synpol D architecture.

The unit remains impervious to major switchboard voltage drops during diesel engine cranking or heavy inductive load startups. The CMA 120 integrates front-panel status/alarm LEDs, dedicated numerical displays (voltage, current, power, frequency, power factor), a backlit LC graphic display for alarms and engine telemetry, and direct membrane navigation pushbuttons. It communicates across adjacent generator sections and power management tiers via isolated high-speed CAN bus (decentralized multi-master topology) and provides serial Modbus RTU (RS-485/RS-422) for remote integration with vessel Alarm and Monitoring Systems (AMS/VMS) or main SCADA networks.

Key Features

1. Decentralized Multi-Master Architecture: Operates with autonomous microprocessor control per generator bay, communicating across a fault-tolerant dual-wire CAN bus so that failure of any single controller cannot bring down the vessel’s automated power generation.
2. Integrated Generator Protection Suite: Combines ANSI protection functions directly inside the controller—including overcurrent (50/51), voltage-restrained time overcurrent (51/27R), reverse power (32R/F), ground fault (51G/N), over/undervoltage (27/59), and over/underfrequency (81O/U).
3. Precision Automatic Synchronizing & Load Sharing: Features integrated dynamic synchronizing with automatic frequency and voltage matching pulses, dead-bus closing interlocks, and active/reactive load sharing (kW/kVAR) via analog bias outputs or digital stepping signals.
4. Extreme Electrical Resilience for Marine Switchboards: Native input tolerance from 14.5 V to 34 V DC prevents microprocessor drop-out during blackouts, main engine starting air cycles, or emergency bus transfers.
5. Field-Serviceable Modular PCB Sub-Rack: Built around standardized internal cards (CMA 122 CPU, CMA 123 PT/CT measurement, CMA 124/125 digital I/O, CMA 126 analog conditioning, and CMA 127 relay driver modules) to facilitate rapid board-level replacement on board without scrapping the entire panel housing.

Model Details

• Manufacturer: ABB (developed in association with Stucke Elektronik)
• Model: CMA 120
• Main Part Number (MPN): 3DDE 300 400
• Alternate Engineering Codes: 3DDE300400, 3DDE-300-400
• Internal Sub-Assembly Motherboard / Frame: CMA 130 AE3
• Internal Daughterboard Card Sets: CMA 122, CMA 123, CMA 124, CMA 125, CMA 126, CMA 127
• Interchangeable Legacy Hardware: Stucke Synpol-D Basic Control Display / SYNPOL D 3DDE300400

Compatibility

• Engine Governing Systems: Direct integration with Woodward (2301A, 723PLUS, 733, Peak 150), Heinzmann (Pegasos, Pandaros series), Barber-Colman, and modern electronic common-rail marine diesel engines (MAN B&W, Wärtsilä, Caterpillar/MaK, Cummins, MTU, Daihatsu, Yanmar).
• Excitation & AVR Systems: Compatible with ABB Unitrol series, Basler Electric (DECS-100, DECS-200), Leroy Somer, Stamford (MX321, MX341), and Mecc Alte digital/analog regulators.
• Medium/Low-Voltage Breakers: ABB SACE (Emax, Megamax), Schneider Masterpact (NW, NT), Siemens SION/3WL, Terasaki AR series (air circuit breaker trip coils, spring charge limits, and closing release interlocks).
• Synpol D System Family: Direct modular compatibility with ABB/Stucke CMA 122, CMA 124, CMA 125, CMA 126, CMA 130 rack backplanes, and peripheral XMA/XIA extension modules.

Our Engineer Expert’s Field Guide

During 20+ years commissioning marine power plants, when a Synpol D CMA 120 triggers a ‘Sync Failure’ or fails to parallel automatically, 9 out of 10 engineers blame the internal synchronizer board. Nine times out of ten, the controller is doing its job and saving your breaker from explosive out-of-phase closure.” — Senior Marine Systems Automation Engineer

1) The Phase Angle & PT Phase-Rotation Trap

Before replacing a unit during drydock or after switchboard maintenance, always connect a dual-channel oscilloscope or calibrated phase-angle meter across X2:1–X2:3 (Bus VT) and X2:4–X2:7 (Gen VT). If technicians disconnected the PT wiring during survey inspections, inverted polarity or phase swap will cause the CMA 120 synchroscope to spin erratically or lock out at a fixed phase angle, preventing breaker closure.

2) Verify Auxiliary DC Rail Noise

The CMA 120 is specified down to 14.5 V DC, but switchboard battery banks coupled with failing transformer-rectifiers frequently introduce AC ripple exceeding 2.5 V RMS. This excessive ripple degrades the analog control signal loops (±10 V DC bias lines to the governor), manifesting as hunting or frequency oscillations once the generator closes onto the busbar. Always verify ripple with an oscilloscope directly at terminals X1:1 and X1:2.

3) CAN Bus Termination Resistance Verification

In modular Synpol D multi-generator setups, always check that the 120 Ω bus terminating resistors are fitted only at the two physical ends of the CAN bus line (e.g., DG1 panel and DG4/Emergency panel). If intermediate CMA 120 units have internal termination enabled or external resistors left wired across X5:1 and X5:2, the total loop resistance drops below 50 Ω, resulting in intermittent CAN bus dropouts, shedding of automated load-sharing, and “Bus Offline” error codes.

Frequently Asked Questions

Can I replace an existing ABB CMA 120 with another unit having a different firmware revision?

Yes, but with strict considerations. While the hardware part number 3DDE 300 400 remains physically and electrically identical across production runs, the firmware version (e.g., Program Version 1.15 or 1.17) dictates CAN bus communication protocols with adjacent generator panels. For seamless automated load sharing, ensure that all CMA 120 units participating on the same physical CAN bus run identical or backward-compatible firmware versions. Firmware chips can be transferred from your existing unit’s CMA 122 processor board if necessary.

How do I clear an active “Internal Fail” alarm on the front LCD?

An “Internal Fail” alarm typically signifies a failed self-test diagnostic across internal daughterboards (such as measurement card CMA 123 or power rail monitoring on CMA 130). Disconnect auxiliary power at X1:1/X1:2 for 60 seconds to execute a full hardware reboot. If the alarm persists upon repowering, check for short circuits on external 24 V DC transmitter feeds or internal PCB hardware faults requiring board repair.

Does the CMA 120 require an external synchronizer unit to parallel generators?

No. The ABB Synpol D CMA 120 houses an internal digital auto-synchronizer. It calculates phase difference, voltage differential, and slip frequency between the incoming generator and live busbar, directly driving the breaker close coil output relay when synchronization criteria are achieved.

How is parameter calibration handled on the CMA 120 without a dedicated programming laptop?

All fundamental operational thresholds (overcurrent trip setpoints, delay timers, frequency margins, and voltage tolerances) can be programmed directly via the front membrane keypad and LCD display. Access is protected by multi-level engineering passwords to prevent unauthorized tampering during sea operations.

Can the CMA 120 be Megger tested alongside the switchboard?

Never apply high-voltage Megger or insulation resistance test voltages directly to the CMA 120 terminals. Prior to conducting 500 V or 1000 V insulation tests on marine switchboards, all multi-pin plug-in connectors (X1 through X5) must be unplugged from the rear of the CMA 120 chassis to prevent instant destruction of internal surge arrestors, optocouplers, and measurement transformers.