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Diesel · Shaft · Emergency · AVR
Generator
Main, auxiliary, shaft and emergency generators — AVR hunting, voltage drift, reverse-power trips, sync failures, parallel load imbalance.
Service available at all US ports — 24/7 worldwide. Our next available technician contacts you within 1 hour.
Symptom checklist
What we hear from the bridge.
- ›AVR hunting ±30V at light load (Stamford MX341/MX321)
- ›Reverse power trip during PTI/PTO transition on shaft generator
- ›Synchroscope drift, breaker fails to close on dead bus
- ›Light load below 20% causes voltage collapse
- ›Emergency genset fails to auto-start within 45s (SOLAS II-1/43)
- ›Load sharing imbalance ±15% kW between parallel D/Gs
- ›Excitation lost shortly after breaker close
- ›Governor surge after step load above 60%
Likely root causes
Where the fault usually lives.
- ›Aged AVR PCB capacitor drift, sensing CT phase reversed after overhaul
- ›Slip ring carbon dust on exciter brushes
- ›Loose CT terminations on load-share line
- ›Governor actuator hysteresis combined with mismatched droop
- ›Sulphated start battery on emergency genset
- ›Loss of phase reference on sync panel, failed check-sync (25) relay
Equipment we bring
Calibrated test equipment, class-acceptable reports.
- OMICRON CMC 356 secondary injection
- Megger MIT525 5kV insulation tester (PI/DAR)
- Hioki PW3198 power quality analyser
- FLIR T540 thermography
- Fluke 438-II motor & generator analyser
- DEIF / Selco / Woodward service tools
Reports compatible with DNV · BV · ABS · Lloyd's · TL · RINA · ClassNK · IRS.
Often needed together
Parts most often requested with this service.
- avr spares
- governor modules
- sync relays
- start batteries
FAQ
Common questions for this system.
- Which AVR makers do we work with?
- Stamford (Cummins), Mecc Alte, Marathon, Leroy-Somer and Basler. Replacements are sourced through approved marine channels with declaration.
- How long does an AVR diagnostic attendance typically take?
- Diagnostic attendance: four to six hours per set. Replacement and commissioning: a further three to four hours including load-step testing and parallel verification.
- Can we attend during cargo operations?
- Diagnostics that do not require taking the set offline can be performed during normal operation. Replacement and commissioning typically require a planned shutdown of the affected set; we coordinate with the chief engineer.
Have a vessel calling?
Three quick questions — port, when, contact. Our next available technician will contact you within 1 hour.