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Home›Repair guides›Marathon›Disassembly Instructions

Marathon — Disassembly Instructions

Repair & overhaul · Generator

From a Marathon service manual — check it applies to your exact model before use.

Before you start

  • Do not apply any force to generator fan for lifting or rotating generator rotor.
  • Special care should be used in rotor assembly removal, or winding damage could result.
  • Failure to follow instructions may reduce the generator's stated electrical performance.

Procedure

  1. Remove conduit box cover.
  2. Disconnect F1 and F2 leads of exciter stator from regulator and power and sensing leads from main stator leads.
  3. Remove front bearing cap screws and washers. Two bearing: this step does not apply.
  4. Remove adaptor screen. Two bearing: remove rear bracket screen.
  5. Remove adaptor mounting screws and washers. Remove adaptor from body assembly. Two bearing: remove rear bearing lock screws and washers; remove rear bracket mounting screws and washers; remove rear br
  6. Remove drive disc mounting screws and washers. Remove drive discs and disc spacers (if equipped). Two bearing: this step does not apply.
  7. Slide a pipe slightly larger in ID than shaft extension OD over shaft extension. Wrap lifting strap around shaft between fan and rotor core. Connect to hoist (1000# or more).
  8. Raise rotor assembly until centered in stator assembly (rotor turns freely). Carefully pull rotor assembly out while applying force on pipe to maintain centering.
  9. Set rotor assembly on suitable cradle to prevent winding damage.
  10. Remove conduit box mounting nuts and lift off the box.
  11. Mark both front bracket and body assembly within 0.030 inch to assure proper alignment at reassembly. Remove front bracket mounting screws and washers and lift off bracket and exciter assembly.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Specs & values

  • within 0.030 inch

Source: Marathon service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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