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We recommend generator maintenance as per below. |
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Field Winding (1) |
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Field Winding (2) |
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| In case of winding-short |
| Measure impedance at decreasing number of rotations or checking of no-load saturation properties at test-running, these are effective methods |
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Retaining Ring |
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| Stress Corrosion Cracking |
| Replacement of 18Mn-5Cr retaining ring to18Mn-18Cr retaining ring that has excellent anti-SCC properties |
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Bearing |
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Exfoliation, wrinkle or contact of metal caused by repetition of start & stop and vibration due to rotation or load fluctuation.
Increasing vibration caused by deterioration of insulation plate. |
| Visual Inspection, NDT (Non-Destructive Test), Clearance adjustment |
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Seal Ring |
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| 4 piece type: deterioration of spring strength. 2 piece type: Impossible to repair after ingress of foreign material. |
| 4 piece type: Repair and reuse within tolerance. 2 piece type: Recommendation to prepare spare seal rings |
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Packing Gland |
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| Hydrogen gas leakage caused by deterioration of packing due to thermal stress and repetition of start & stop. |
| Every 2 years: Fastening bolts Every 15 years: Replacement of packing |
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High Voltage Bushing |
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AC Exciter |
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Stator Core |
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| Looseness, Short circuit of lamination caused by over excitation |
| Tightness check, EL-CID Test |
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Stator Winding |
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Stator Winding Insulation for Water Cooled Machine |
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Stator Winding Insulation |
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