Confidential © Siemens Energy, Inc. 2015 All rights reserved.
Modern Generator Designs / Robotic Core Stacking David Charlton
Generator Users’ Group (GUG) / November 2015
November 2015 Generator Users’ Group Page 2 Confidential © Siemens Energy, Inc. 2015. All rights reserved.
Table of Contents
Quality Systems
Stator Core Design & Assembly
Stator Core Manufacturing / Stacking
• Individual Laminations
• Donut Packs
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Generator manufacturing 150 MVA - 1200 MVA units Machining, winding, assembly &
balance Generator and exciter service Rewinds, partial repairs,
modernizations
Steam turbine manufacturing Machining, assembly & balance Full replacement elements Turbine & valve service Rotor, stator complex weld repair Nuclear / fossil valves & actuators Rebuilds & replacements
Generator Rotor Generator Stator
Steam Turbine LP Steam Turbine Rotor Steam Valve
Gas turbine manufacturing Machining, fabrication, assembly
and balance Gas turbine service Rotor repair, stator repairs,
replacement, LTE Gas Turbine Rotor Gas Turbine Stator Gas Turbine
Generator
Charlotte Products & Services
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Stator Core Design
Supports the stator windings Magnetic path for rotor flux Two types of stator core stacking
techniques • Individually stacked laminations • Stator core donuts
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Stator Core Design
Stator Core Cooling
Radially cooled
• Conventional air
• Hydrogen
Axially cooled
• Conventional air
• Hydrogen
Axially Cooled Core Radially Cooled Core
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Stator Core Manufacture
Individually stacked stator laminations
• New cores robotically stacked
• Replacement cores – hand stacked
Vertically stacked in factory or field
• Requires rotating frame
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Robotic Stator Core Stacking
Programmable robots
used for stacking
Laminations stacked in segments, then inspected for Critical to Quality attributes
Approximately 150,000 laminations per generator core
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Stator Core Robot Stacking Video
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Lamination Lifting & Core Stacking Process
The segment of iron is moved to the core stacking station Tooling (pins & drifts) for correct positioning and core shape
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Stages of Core Stacking
Pressure for core consolidation
Fully stacked, ready for turn down
Stacking
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Measurements of Core Stack (Bonded Core Packs “Donuts” and Dry Stack Core)
Inspection & measurement of core stack
• Visual inspections
• Critical to Quality measurements
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Moving a Stacked Core to Winding
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Wound Core Assembly
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Global Vacuum Pressure Impregnation Chamber
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Modern Stator Core Mounting
Stator core is spring mounted on the bedplate by steel spring assemblies to:
• Isolate double frequency core vibration
• Limit torque build up during power system faults
Spring suspension mounting along the generator
Spring bar is welded to individual spring brackets that are connected to stator key bars
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Stator Core: Turbine Deck Restack Options Bonded Core Pack “Donut” Design
Donut Core (i.e., bonded core packs) • Pre-manufactured core sections • Allows horizontal core stacking in the field • Electrically tested prior to shipment • Highly consolidated core • OEM & OOEM core replacements
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Donut Installation Trolley
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Air-Cooled Generator – Final Assembly
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H2-Cooled Generator – Final Assembly