ABB Marine Shaft Generator

Insulation resistance (IR) test with megohmmeter (Megger): apply DC voltage approx. 500V between winding and ground. Measure leakage current. Minimum requirements per maritime regulations: >2 MΩ (up to 5A); >1 MΩ (10A); >100 kΩ (100A); >25 kΩ (>200A). Normalize measured values to 40°C (IEEE 43-2013). Perform trend analysis over time. Disconnect AVR before test (DAR method). Check surface, generator and environment for dryness before test (maritime humidity).

Visually inspect operating condition of footings and bearing shells; check bearing lubrication and temperature (document D-end and N-end separately); measure surface temperatures with thermometer or IR camera. Measure operating vibration (mm/sec or µm); record deviating values. For regreasing bearings, top up grease per manufacturer specification. Check tightness of bearing shields against salt water and moisture.

Visual inspection of winding for cracks, burn marks, discoloration, loose connections. Perform resistance measurement of insulating material. Perform tan-delta & capacitance measurements (partial discharge analysis) to detect lamination or corona damage (ABB Ability LEAP program). Assess insulation system condition (VPI impregnation). Measurement duration approx. 4-6 hours.

Visually inspect AVR units for corrosion, moisture ingress, loose contacts (salt water environment). Check voltage output on AVR display or meter. Perform AVR test program: verify setpoint voltage, test response to load change, test UEL/OEL (under-/overexcitation limiter) function. Check wiring and connectors for corrosion. Solvent cleaning if necessary. Secure replacement AVR unit.

Inspect fan blades for salt deposits, corrosion, mechanical damage. Clean air channels and cooling flanges (remove salt spray deposits). Check water cooler for leaks, corrosion, mineral deposits (for water-cooled variants). Measure temperature rise during operation: stator winding U/T1, V/T2, W/T3; bearing shells D-end and N-end. Document ambient temperature. Should be >5°C, relative humidity <75%; keep machine temperature >= dew point. Clear cooling before restart.

Perform torque check on fastening bolts (manufacturer specification); loosen/reposition if necessary. Inspect power cable connections for visible corrosion, loose contact, deformation. Verify bearing lubrication before start (regreasable bearings). Consult commissioning report from Annex 5 of AMG Manual. Verify all settings again on site. Perform voltage/current measurements. Test safety devices. Complete and sign commissioning test protocol.