Back to services
440/230V · Lighting · HV step-down
Transformer
Step-down transformers, lighting transformers, HV (6.6 kV / 11 kV) units. Winding ratio, vector group, no-load and load loss tests.
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.
- ›Transformer hum and oil weep on 440/230V step-down
- ›Insulation drop on 220V lighting bus
- ›Hot core, top temperature above 95 °C
- ›Tap changer stuck after surveyor inspection
Likely root causes
Where the fault usually lives.
- ›Loose terminal lug, partial discharge
- ›Cooling fan failure on dry-type
- ›Oil moisture above 50 ppm on liquid-filled
Equipment we bring
Calibrated test equipment, class-acceptable reports.
- Megger DLRO10HD low-resistance ohmmeter
- Megger TTR300 transformer turns ratio tester
- Megger MIT525 5kV insulation tester
- FLIR T540 thermography
Reports compatible with DNV · BV · ABS · Lloyd's · TL · RINA · ClassNK · IRS.
Often needed together
Parts most often requested with this service.
- transformer spares
- cooling fans
- tap changers
FAQ
Common questions for this system.
- Which marine transformer types do you test and service?
- 440/230V step-down lighting and galley transformers, 6.6 kV and 11 kV main HV transformers on LNG carriers and cruise ships, plus isolation transformers for shore-power and bow-thruster VFD front ends. Standard test set includes Megger TTR300 turns-ratio, Megger MIT525 5 kV insulation, OMICRON CPC 100 winding resistance and FLIR T540 thermography under load. Dielectric oil sampling is sent to a US-based ISO 17025 lab for dissolved-gas analysis when DGA is in scope.
- How long does a routine transformer test take?
- A 440/230V lighting transformer routine (visual, IR, TTR, thermography on load) is two to three hours including isolation. A 6.6 kV main bus tx full routine with OMICRON CPC 100 sweep, oil sample draw and bushing tan-delta is six to ten hours, requiring a planned blackout window agreed with the Chief Engineer. We schedule HV work around cargo operations and bring all our own LOTO locks plus a calibrated Salisbury HV glove set rated 17 kV.
- Will the transformer test report be accepted for the special survey?
- Yes. Reports are in the format expected by DNV, BV, ABS, Lloyd's Register, ClassNK, RINA, TL and IRS for the electrical special survey item. We include Megger TTR300 calibration cert, MIT525 5 kV insulation readings with polarization index, OMICRON winding resistance, thermography images with delta-T against ambient, and DGA lab report where applicable. The chief engineer's PMS is updated with the next 30-month re-test interval before we sign off.
Have a vessel calling?
Three quick questions — port, when, contact. Our next available technician will contact you within 1 hour.