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TYPICAL ROTOR REWINDING PROCESS

WORKSHOP & FACILITIES

1. Rotor Rewinding Process (Typical)

DOOSAN POWER SERVICESTECHNICAL SOLUTIONS – TYPICAL STATOR REWINDING PROCESS

1. Rotor Rewinding Process (TYPICAL)

Unpacking & VisualCheck

Disassemble Conn.Bars

Electrical Test

⋅ Unpack & check surface of rotor

⋅ Remove bore plug and disassemble conn. bars

Cleaning of Conn.Bars⋅ Remove rust on the

conn. bars

Cleaning of RotorShaft⋅ Remove rust

DisassembleConnectors⋅ Disassemble

connectors by torch

Removing RetainingRing⋅ Heat the retaining ring

with induction heater

N2 Leakage Test⋅ Leakage test on

the plug with N2

⋅ Insulation resistance⋅PI impedance⋅Winding resistance

Disassemble Coils⋅ Disassemble coils from

the rotor

NDT of Rotor Shaft⋅ UT on the dovetail slots⋅ Slot wedge dovetail,

journal

DOOSAN POWER SERVICESTECHNICAL SOLUTIONS – TYPICAL STATOR REWINDING PROCESS

Painting the Shaft

Cleaning of Disassembled Coils

⋅ Paint body and spindle except journals, deflector, coupling holes and shrinkage fit

⋅ Remove vanish and burr from the surface and clean coils with acetone

Finishing of Minor Parts⋅ Clean retaining rings,

retaining ring keys, wedges, centering ring, blocks and amortisseur segments

NDT of Minor Parts⋅ PT: Retaining rings,

retaining ring keys and wedges

1. Rotor Rewinding Process (TYPICAL)

DOOSAN POWER SERVICESTECHNICAL SOLUTIONS – TYPICAL STATOR REWINDING PROCESS

Preparation & Set-up

Disconnecting #6 Coils

Brazing New Coils

⋅ Prepare necessary materials

⋅ Set the rotor on v-blocks

⋅ Disconnect the deformation of coils

⋅ Replace the old ones with new copper and braze

Temporary Block Assembly

Baking

Retaining Ring Insulation Assembly

⋅ Assemble the temporary blocks for baking

⋅ Bake the resin to be attached on coils

⋅ Assemble the retaining ring insulation and amortisseur segments

Main Lead Assembly⋅ Assemble the main lead

on the conn. bar

Electrical Test⋅ Hi-pot test for each coil⋅ Insulation resistance

and PI

Brazing Main Lead⋅ Braze the main lead

with #1 coil by using an induction machine

Coil Assembly⋅ Assemble the coils

from #1 through #7

1. Rotor Rewinding Process (TYPICAL)

DOOSAN POWER SERVICESTECHNICAL SOLUTIONS – TYPICAL STATOR REWINDING PROCESS

Retaining Ring Assembly⋅ Heat the retaining ring up

to a maximum of 325°C, maintain it for 4 hours, and then assemble the retaining ring

Cleaning & Painting⋅ Clean journals, collector rings

and outside surfaces of rotor⋅ Paint wedges and coupling areas

1. Rotor Rewinding Process (TYPICAL)

Final Electrical Test⋅ Hi-pot test at 3,000V, insulation

resistance and PI⋅ Winding resistance, impulse

test and R.S.O⋅ After hi-pot, check the

insulation resistance

Rotor Insertion⋅ Protect the journal with anti-

rust and cover fiber board, and transport the rotor into the generator