GYRO COMPASS SYSTEM
TOKYO KEIKI INC.
Manufacturer: TOKYO KEIKI INC. — earlier units may carry the TOKIMEC name
Country of Origin: Japan
Model: TG-8000 Series
Product Type: Marine Gyrocompass / True Heading Reference System
Associated Series: TG-8500
Marine Application: True-heading supply for ship navigation, autopilot, radar, ECDIS, AIS, VDR/S-VDR, heading repeaters and other bridge equipment.
The TOKYO KEIKI TG-8000, widely encountered on older vessels under the TOKIMEC TG-8000 name, is a mechanical marine gyrocompass designed for standard IMO ship applications.
TOKYO KEIKI's TG-series design uses a sensitive gyroscopic element suspended in liquid by suspension wires. The TG-8000 became a widely installed heading reference because of its reliability, fast follow-up performance and ability to distribute heading information to multiple bridge systems.
The SM MARINE SERVICE™ stock photograph shows multiple complete TG-8000 systems, including master compass assemblies and their associated control units.
A gyrocompass automatically establishes true north by using the characteristics of a gyroscope together with Earth's rotation and gravity. Unlike a magnetic compass, its heading reference is not based on Earth's magnetic field.
The TG-8000 therefore provides a stable true-heading signal to the ship's navigation network.
Typical heading users include:
Autopilot • Radar • ECDIS • AIS • VDR/S-VDR • Course Recorder • Heading Repeaters • Steering Systems • Other Bridge Navigation Equipment
The TG-8000 is intended for standard IMO ship applications, while the related TG-8500 was developed for high-speed craft.
Important TG-8000 characteristics include:
The TG family was developed from earlier Tokyo Keiki gyro technology installed on thousands of vessels worldwide.
Verified technical information for the TG-8000 includes:
| Specification | TG-8000 |
|---|---|
| Equipment | Marine Gyrocompass |
| Application | Standard IMO vessel |
| Normal AC Power | AC 100/220 V, 1-phase, 50/60 Hz |
| Normal Consumption | Approx. 70 VA |
| Emergency Supply | DC 24 V |
| Emergency DC Consumption | Approx. 3 A |
| Settling Point Error | ±0.3° |
| Fast Follow-Up | Maximum 75°/s |
| Serial Heading Outputs | 5 |
| Serial Interface | IEC 61162-2 |
| Repeater System | DC 24 V step-motor type |
| External Repeater Ports | 9 standard circuits in referenced configuration |
These values are supported by Tokyo Keiki technical documentation; exact shipboard configuration should always be confirmed against the unit's nameplate and vessel drawings.
The large upper enclosure visible in the SM MARINE SERVICE™ photograph is the TG-8000 Master Compass. It houses the precision gyro mechanism and associated sensitive-element assemblies responsible for establishing true heading.
The sensitive element is the heart of the mechanical gyrocompass. Its correct operation depends on rotor performance, suspension, servo control and associated electronic circuits.
The separate rectangular enclosure provides system control, monitoring, heading interfacing and alarm functions. The operator/control panel allows engineers to monitor gyro operation and access operating information.
The system incorporates azimuth and horizontal servo control. Tokyo Keiki maintenance documentation identifies parameters including damping gain, azimuth servo gain, horizontal servo gain and leveling servo gain.
Heading information can be distributed to repeaters and other bridge equipment using step and serial interfaces.
The TG-8000 can serve as the primary true-heading source aboard:
Cargo Ships • Bulk Carriers • Tankers • Container Ships • LNG/LPG Carriers • Passenger Ships • Offshore Support Vessels • Research Ships • Merchant Vessels
Reliable gyro heading is especially important because one gyrocompass can simultaneously feed numerous safety-critical bridge systems.
Check the main AC supply, emergency DC supply, control-unit power circuits, breakers, connectors and internal power electronics before replacing major components.
Compare the gyro indication against an independent heading reference. Check speed/latitude-related inputs, system parameters, sensitive-element condition and servo operation.
The official TG-8000 maintenance documentation specifically includes records for zero-cross error occurrence, maximum zero-cross error and occurrence history. Repeated zero-cross errors require proper technical investigation rather than repeated resets.
The TG-8000 maintenance check sheet also records encoder error occurrences, making encoder-related faults a documented diagnostic area.
If the master heading is correct but a repeater does not follow, inspect the relevant 24 V repeater output, distribution wiring, terminal connections and the repeater itself.
If the master compass displays correctly but external equipment loses heading, investigate the serial interface, output configuration, cable continuity and receiving equipment.
TG-8000 maintenance parameters include configuration for GPS and LOG connections. Incorrect or missing external inputs should therefore be checked at both configuration and wiring levels.
Abnormal azimuth or horizontal servo behaviour may require checking servo gain, mechanical movement, feedback circuits and sensitive-element condition. Such adjustment should be undertaken by qualified gyrocompass technicians.
Documented maintenance and diagnostic areas include:
Zero Cross Error • Encoder Error • SCC Reset History • Azimuth Servo Deviation • Horizontal Servo Deviation • GPS Connection • LOG Connection • External Input Status
Exact alarm interpretation should always be taken from the TG-8000 service or maintenance manual. Alarm codes should not be guessed.
The TG-8000 is a precision mechanical gyrocompass, so preventive maintenance is particularly important.
Engineers should periodically inspect the master compass, control unit, connectors, grounding, ventilation and external heading connections.
Check alarm/error history instead of simply clearing recurring faults.
Verify the heading at repeaters and all connected bridge equipment.
Inspect the condition of the sensitive element and gyro assembly according to the manufacturer's prescribed maintenance procedures.
Record important service parameters before adjustment. The official maintenance sheet contains numerous reference values specifically for this purpose.
Internal gyro adjustments, sensitive-element work and servo calibration should be performed by personnel experienced with Tokyo Keiki/Tokimec gyrocompasses.
Common TOKYO KEIKI / TOKIMEC TG-8000 spare-part requirements can include:
Complete TG-8000 Master Compass • Control Unit / Control Box • Sensitive Element • Gyro Sphere / Gyro Assembly • Control Panel • PCB Assemblies • Servo Electronics • Power Supply Parts • Heading Interface Boards • Repeater Output Components • Internal Cables • Connectors • Mechanical Components • Complete Tested Replacement Unit
SM MARINE SERVICE™ can support sourcing of:
New • Used • Refurbished • Reconditioned • Tested Working TG-8000 equipment and spare parts, depending on stock and market availability.
For legacy vessels, matching the exact existing configuration is important. Buyers should ideally provide photographs of the nameplate, master compass, control unit and required spare part before ordering.
The TG-8000 has a very large legacy installation base. Industry documentation describes the design as being based on earlier TG models installed on more than 8,000 ships, while later Tokyo Keiki material reports more than 17,000 TG-8000 master compass units shipped from its Japanese factory.
Many ships therefore continue to require TG-8000 master compasses, control units, sensitive elements and electronic spare parts rather than immediately replacing the complete heading system.
Tokyo Keiki's newer TF-900 fiber-optic gyrocompass documentation also specifically addresses retrofit from existing TG-8000-series systems and states that existing accessories such as repeaters can be retained in applicable configurations.
What is the TOKYO KEIKI TG-8000?
It is a marine gyrocompass designed to provide accurate true-heading information to the ship and connected bridge navigation systems.
Are TOKIMEC TG-8000 and TOKYO KEIKI TG-8000 related?
Yes. TOKYO KEIKI is the manufacturer formerly known as TOKIMEC, which is why older marine equipment may carry TOKIMEC branding while later units show TOKYO KEIKI.
Where can I buy a TG-8000 gyrocompass?
SM MARINE SERVICE™ can support sourcing of complete TG-8000 master compasses, control units and related spare parts subject to availability.
Can I buy a used or refurbished TG-8000?
Yes. Used, tested, refurbished and reconditioned units can be useful for maintaining existing legacy installations when compatibility and condition are properly verified.
Are TG-8000 gyro sphere and sensitive-element spare parts available?
Availability varies because the TG-8000 is a legacy mechanical gyro system. SM MARINE SERVICE™ can assist with sourcing specific assemblies and replacement equipment.
What is the difference between TG-8000 and TG-8500?
The TG-8000 was designed for standard IMO ship applications, while TG-8500 was intended for high-speed craft applications.
What are common TG-8000 problems?
Typical service areas include heading errors, servo problems, zero-cross errors, encoder errors, external input problems, repeater-output faults and sensitive-element issues.
What newer technology can replace a TG-8000?
Tokyo Keiki documents its TF-900 fiber-optic gyrocompass as suitable for retrofit applications involving existing TG-8000-series installations.
Can SM MARINE SERVICE™ supply TG-8000 equipment worldwide?
Yes. Complete units and spare parts can be sourced and shipped worldwide subject to stock and equipment condition.
The TOKYO KEIKI / TOKIMEC TG-8000 Gyrocompass is a high-reliability marine true-heading system designed for standard IMO vessel applications. The system combines a precision master compass, sensitive gyro element, control unit and heading interfaces to provide true-heading information to autopilot, radar, ECDIS, AIS, VDR and repeater systems. SM MARINE SERVICE™ supports worldwide sourcing of TG-8000 master compasses, control boxes, sensitive elements, gyro assemblies and replacement spare parts.
Marine Automation & Navigation Equipment Supplier
Available Condition:
• New Equipment • Used Equipment • Refurbished Equipment • Reconditioned Equipment
Stock Location:
• Bangladesh • China
Services:
• Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing
Contact Information
SM MARINE SERVICE™ Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh
Mobile / WhatsApp / Viber: +88 01818 929292
Email: info@smmarineservice.com
Website: www.smmarineservice.com
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