Offshore · L2 maintenance · April 2026
L2 maintenance on an ABB 37 MVA generator aboard an FPSO
Offshore operation aboard an FPSO · Mexico · April 2026
Project summary
What the service covered
An ABB AMS 1250 LE generator rated at 37 MVA, 11 kV and 1,800 rpm received L2 maintenance in a marine environment. The service assessed the main windings, excitation system, PMG and rectifier diodes.
The April 2026 report documented satisfactory electrical results and recommended continued monitoring. External corrosion remained a finding requiring specific attention.
37 MVA
Nameplate rating
ABB AMS 1250 LE · 11 kV
L2
Completed scope
Onboard maintenance · April 2026
Satisfactory
Electrical result
Reported condition at completion; continue monitoring
Unresolved
External corrosion
Requires attention and a specific scope
Define a feasible onboard scope
Access and available space constrain handling of an offshore generator. The preliminary survey identified that rotor removal was not feasible at the existing location without first resolving the lifting plan and required equipment.
- 37 MVA synchronous generator in a marine environment
- Moisture as a relevant condition when interpreting tests
- Clearance and handling arrangements to verify before major disassembly
Equipment serviced
Offshore synchronous generator
- OEM
- ABB
- Model
- AMS 1250 LE
- Rating
- 37,000 kVA
- Voltage
- 11 kV
- Speed
- 1,800 rpm
L2 maintenance and electrical assessment
The intervention included inspection of accessible areas and testing of electrical components. Interpretation of the results considered the site's environmental conditions.
Completed activities
- Internal visual inspection of windings, connections and accessible areas
- Insulation-resistance and winding-resistance measurements
- Step-voltage, surge and partial-discharge assessment as documented in the report
- PMG, excitation-system and rectifier-diode checks
- Recording of external corrosion and follow-up recommendations
Technical reference
Technical report TMS-SE-RE-10
Findings and follow-up
Electrical results were within the report's assessment criteria. Some polarization and absorption indices were slightly low; the report linked them mainly to moisture in the marine environment.
Internal inspection did not record excessive contamination, oil leaks or significant visible damage in accessible areas. Externally, corrosion was identified on covers, guards, the structure and fasteners.
The preliminary survey and L2 maintenance are different scopes. The documented service did not include rotor removal or an L3/L4 overhaul. A major intervention requires prior resolution of space, lifting and onboard logistics.
The results describe the condition observed in April 2026. Scheduling the next service should consider current measurements, corrosion progression and the client's operating window.
Questions about this service
Did the service include rotor removal?
No. L2 maintenance was performed. The preliminary survey identified space and handling restrictions that must be resolved before proposing removal.
Was the external corrosion resolved?
The completion report records external corrosion as a finding still requiring attention. Treatment needs a specific scope and an assessment of the current condition.
What information is needed to assess another offshore generator?
Manufacturer, model, rating, location, symptoms and outage window. Major handling operations also require review of access, space and available lifting equipment.
Documentary traceability
Assessment against the service report
Technical report TMS-SE-RE-10 · April 2026
The client is described by sector to protect commercial information. Equipment data and service results remain tied to the original TEMISA service record. The findings describe the documented intervention, not the generator's current condition.
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