System Overview: Alphatron AlphaMidiCourse Mk2 Gyrocompass
The Alphatron AlphaMidiCourse Mk2 is a high-reliability, Wheelmark MED-approved marine gyrocompass developed by Alphatron Marine (JRC) for deep-sea commercial vessels, container ships, tankers, bulkers, and offshore service vessels. Compliant with IMO Resolution A.424(XI) and ISO 8728, the AlphaMidiCourse Mk2 delivers exceptional heading accuracy, rapid settling, and long operational service intervals.
Featuring a sealed, high-inertia gyrosphere suspended in specialized supporting liquid, an advanced digital follow-up servo system, and comprehensive serial NMEA 0183 ($HEHDT, $HEROT) and step transmission outputs, the AlphaMidiCourse Mk2 is widely deployed across European and Asian merchant fleets.
Technical Specifications: AlphaMidiCourse Mk2
| Parameter | Specification Details |
|---|---|
| Approval Standards | IMO A.424(XI), MSC.116(73), ISO 8728, Wheelmark MED Approved |
| Gyrosphere Element | Twin-rotor hermetically sealed gyrosphere suspended in supporting liquid |
| Settling Time | < 3 hours cold start (< 1 hour with quick-settling heading pre-set) |
| Static Accuracy | ≤ ±0.1° secant latitude |
| Dynamic Accuracy | ≤ ±0.4° secant latitude under rolling/pitching up to ±30° |
| Follow-Up Speed | Up to 100°/second tracking capability |
| Heading Interfaces | 4x RS-422 NMEA 0183 ($HEHDT, $HEROT at up to 40 Hz), 2x Step (24V DC), Synchro, Alarm relays |
| Operating Voltage | 115 / 230 V AC (50/60 Hz) main with seamless 24 V DC battery fallback |
| Power Consumption | Approx. 75 W steady state (130 W starting) |
Core Units, PCBs & Field Replacement Spares
| Component | Part Number | Description & Function |
|---|---|---|
| Gyrosphere Element | AMC2-SPHERE-ASY | Precision twin-rotor gyrosphere element (replacement interval: 3–4 years) |
| Supporting Fluid Kit | AMC2-FLUID-SET | Specialized electrolyte supporting fluid bottle (approx. 1.2 Liters) |
| Rotor Inverter PCB | AMC2-PCB-INV | Generates 3-phase high-frequency power driving gyrosphere rotors |
| Main CPU & Control Board | AMC2-PCB-CPU | Processor board executing latitude error correction and communication |
| Follow-Up Servo Driver | AMC2-PCB-SRV | Servo amplifier driving the azimuth phantom ring motor |
| Power Supply Unit (PSU) | AMC2-PSU-ASY | Dual AC/DC auto-switch power supply conditioning assembly |
| Azimuth Follow-Up Motor | AMC2-MTR-AZ | Brushless servo motor with precision reduction gear |
| Overhaul Gasket & Seal Kit | AMC2-GSK-KIT | Chemical-resistant rubber seals, O-rings, and thermal washers |
Seanav Service Procedures for AlphaMidiCourse Mk2
Seanav Marine provides certified maintenance, gyrosphere exchanges, and emergency repairs for the AlphaMidiCourse Mk2:
- Routine Annual Inspection: Testing flotation current, verifying fluid level through the sight glass, checking cooling fan airflow, and checking slip rings.
- Container Overhaul & Gyrosphere Exchange: Draining supporting liquid, cleaning container electrode pins, replacing O-rings, installing certified gyrosphere, and refilling with fresh fluid.
- Dynamic Heading Calibration: Verifying follow-up responsiveness, nulling optical pickoff sensors, and testing automatic GPS speed/latitude correction.
- Repeater & Bridge Distribution: Testing RS-422 telegram integrity and synchro/step synchronization across all bridge repeaters.
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