WF.Speed Increaser Replacement-Sources Sought Summary SOW.R3_27 Aug 2026.pdf

U.S. Army Corps of Engineers (USACE) Sources Sought Notice

Summary Scope of Work

Project Title: WEBBERS FALLS UNIT 1 SPEED INCREASER REPLACEMENT

Project Location: Webbers Falls Powerhouse, Oklahoma

Part 1: Project Description

The U.S. Army Corps of Engineers (USACE) is seeking sources capable of executing the complete replacement of the Unit 1 speed increaser gearbox. The scope of this project includes the design, fabrication, testing, and installation of a new, fully operational speed increaser system.

The comprehensive scope of work includes, but is not limited to:

Design & Engineering: Complete design of a new speed increaser gearbox suitable for a 25 MW

3. The government may consider delivery of two identical units – one to be installed onsite and one to be placed into long-term storage as a spare.

Manufacturing & Fabrication: Supply of all new components for a new speed increaser which will replace the existing Unit-1 gearbox. The USACE is currently considering a that pairs a low-speed planetary drive stage with a parallel-shaft high-speed stage. This arrangement facilitates shaft alignments. However, the USACE remains open to consideration of alternative design approaches that may better suit the application.

Site Work & Installation:

Full disassembly and removal of the existing Falk speed increaser gearbox.

Inspection and preparation of the existing foundation and site.

Installation, , and precision alignment of the new speed increaser system.

Commissioning and testing to ensure operational readiness.

Part 2: Background

The Webbers Falls Lock and Dam is on the Arkansas River, 432.2 river miles above the junction of the Arkansas and Mississippi Rivers and about 5 miles northwest of the town of Webbers Falls, Oklahoma, in Muskogee County. The power plant is on the right ban

Summary Scope of Work

Figure 1: Webbers Falls Powerhouse Location

Webbers Falls Lock and Dam with power plant is managed by the Tulsa District (SWT) U.S. Army Corps of Engineers. The project was authorized by the River and Harbor Act July 4, 1946, and amended by the Flood recreation. Initial construction began in January 1965; closure was made on November 9, 1970, and the project was placed in useful operation. The lock and dam became operational for navigation in December 1970. The powerhouse is an integral-type structure with three hydro-generating units. Turbine-generator units 1, 2, and 3 were placed into operation in August, September, and November 1973, respectively.

The turbines are slant-axis, Kaplan type each originally rated at 33,800 horsepower, 60.24 RPM at 26.5 feet net head. The angle of inclination is 12 degrees with the horizontal. The units rotate in the clockwise direction when viewed looking upstream. The original turbines were designed and manufactured by Allis-cations were made by Allis-Chalmers to the turbine shaft in the early 1980’s to solve cracking problems. A Turbine Rehabilitation occurred from 2008 to 2018 with work being performed under Contract No. W9127S-08-C-0002. The new turbines were manufactured by Andritz Hydro and uprated to 35,400 horsepower.

The generators are inclined-axis type, connected through a 8.533 to 1 speed increaser driving at 514 RPM.

The generators are rated at 27,000 kVA, 0.95 power factor, 3-phase, 514 RPM, 13,800 volts. The generator is capable of continuous operation at 115%. The generators were manufactured by General Electric Company. A Generator Rehabilitation occurred from 2011 to 2020 resulting in uprate from 20,000 kW per

Summary Scope of Work unit to 25,000 kW per unit, with work being performed under Contract No. W9127S-11-C-0001. The rewind contractor was Andritz Hydro.

Figure 2: Powerhouse Section View – showing turbine, speed increaser, and generator

Existing speed increaser arrangement:

The existing speed increaser consists of a two-stage, self-aligning, parallel shaft, dual-path gear train with a single input and a single output shaft and was originally manufactured by Falk Corporation. The purpose of this arrangement is to reduce the gear tooth load by splitting the load evenly through the two branches.

This results in the transmitted power being carried by two bull gear teeth instead of one. This type of gear arrangement requires precise timing to function properly. Gear shafts are supported by oil lubricated sleeve bearings. Gear mesh areas are lubricated directly by oil nozzles. The gear enclosure is fabricated from plate steel and steel cast blocks with splits on planes through the centers of the shafts. Disruption of timing can result in higher than anticipated gear loading. Existing speed increaser data as follows:

Summary Scope of Work

Manufacturer: Falk Corporation (Rexnord) Input RPM: 60.24 Output RPM: 514 Ratio: 8.533:1 Horsepower: 33,800hp* Inclination Angle: 12 degrees Serial No.: 6-879801-01-E

*Current nameplate reads 33,800 hp.

Figure 3: Speed increaser component

The existing Unit 1 speed increaser has experienced multiple failures over its lifespan, with the most recent failure occurring in July 2021. The unit has been out of service since this failure.

Part 3:

The replacement speed increaser gearbox shall be designed and manufactured to meet the following

3.1 Operating Parameters

Application: Hydroelectric – Slant-axis Kaplan Turbine to Generator

Type: Speed Increaser

Gear Ratio: 8.533:1

Generator Nominal Power: 25 MW

Turbine Speed (Input): 60.24 RPM

Generator Speed (Output): 514 RPM

Nominal Turbine Shaft Torque: 3,086,335 ft-lbs (1)

Orientation: 12 degrees from horizontal

Design Life:

Physical Life: 50 years

Operating Life: 200,000 hours

(1) The 26.4MW applied power at the low speed end of the gearbox is roughly based on a generator power of 25MW divided by a gearbox shall be rated at 25MW.

-speed planetary drive stage paired with a parallel-shaft high-speed stage to facilitate integration with the existing turbine and generator shaft alignments. must be factory assembled and tested, shipped to site without disassembly, and installed/aligned without requiring reassembly and timing adjustment onsite. The USACE remains open to consideration of alternative design approaches that may better suit the application (e.g. non-planetary style parallel-shaft gear train).

Bearings: Sleeve bearings are preferred. The government will consider roller bearings for the planet bearings when a planetary gearbox design is selected. If roller bearings are provided, they shall be preloaded tapered roller bearings. The outer race shall be constructed integrally with the prevent any race creep during operation.

Thrust Bearing: The preferred -use the existing thrust bearing in its current position. However, the USACE remains open to consideration of alternative design approaches that include design of a new speed increaser gearbox that integrates an equivalently sized thrust bearing inside the new gearbox.

Lubrication System: A dry sump, pressure-lubricated system is required whereby gears and bearings receive pressure-lubricated . The oil sump and lubrication system must also be adequately sized to provide pressure-lubrication to the turbine thrust bearing and guide bearings.

without a unit shutdown. Maximum allowable operating sump temperature shall be below 70°C.

Monitoring & Inspection:

Temperature sensors are required to monitor the outer race temperature of all bearings except those designated as planet bearings.

Provisions for visual or borescope inspection of all gear teeth and bearings must be included.

Accelerometer mounts shall be provided to support continuous vibration monitoring – to support predictive maintenance .

Sealing: Labyrinth-type shaft seals are required to prevent contaminant ingress and lubricant loss, with a minimum design life of 200,000 hours.

Part 4: Applicable Design & Quality Standards

Gear Drive System: Must be designed in accordance with the requirements of ANSI/AGMA 2101- E25, ANSI/AGMA 6032-B13, or equivalent standard. Where

Gearing Accuracy:

External Gearing: Must be carburized, ground, and meet ISO 1328-1:2013 Class 5 or better.

Internal Gearing: Must be ion-nitrided, ground, and meet ISO 1328-1:2013 Class 5 or better.

Gear Ratings: The pitting and bending capacity of all gearing must meet the requirements of ANSI/AGMA 2101-E25 with a Bending Safety Factor (SF) > 2.0 and Macropitting Safety Factor (SH) > 1.41.

Bearing Life:

Sleeve Bearings: Rigidly supported, oil- -bearings with minimum design life of 200,000 hours at rated load conditions. Calculate and design journal bearings in accordance with ANSI/AGMA 6001-F19, ANSI/AGMA 6032- B13, ISO 7902-1, 7902-2, and 7902-3.

the most conservative approach shall govern.

Rolling Bearings: The minimum basic L10 bearing life (ISO 281) and L5mr life (ISO/TS 16281:2025) shall be 200,000 hours at rated load conditions. Rolling bearings shall be in accordance with ANSI/AGMA 6001-F19 and ANSI/AGMA 6032-B13, and shall be selected based on their suitability for the application, load capacity, predicted life, speed limitations, and lubrication. Outer races shall be pinned to prevent rotation relative to housing bores.

conservative approach shall govern.

Shafting: Must be designed in accordance with ANSI/AGMA 6001-F19 and ANSI/AGMA 6032-B13.

govern.

For gearbox designs that include split path parallel shaft gear reduction, strain gages shall be included in the design to monitor load sharing between the split path gearing and shafting.

Forging: Must comply with ASTM A290/A291 standards.

Welding: Must be performed in accordance with AWS D1.1.

Metallurgy: Testing and inspection procedures must meet the requirements of AGMA 923, ANSI/AGMA 6033, and the standards they reference.

Part 5: Quality Assurance & Government Oversight

To ensure compliance with all technical and operational requirements, the Contractor shall accommodate the following Government oversight requirements:

5.1 Design Phase Hold Points: The Contractor’s design schedule must include mandatory Government hold points. The Government will review and must formally approve all critical design submittals—including but not limited to design calculations, shop drawings, and product data— prior to the Contractor proceeding with any material procurement or manufacturing activities.

5.2 Manufacturing & Testing Witness Points: The Contractor’s production schedule must accommodate Government witness hold points during the manufacturing process and Factory Acceptance Testing (FAT). The Government reserves the right to physically inspect critical shipment to the Webbers Falls Powerhouse site.

Part 6: Required Contractor Capabilities

Firms must demonstrate established capabilities and experience in the following areas:

1. Gear Design & Manufacturing: Design and production of high-horsepower gears in full accordance with the standards listed in Part 4.

2. Heavy Machining & Heat Treatment: -treat large gears, up to 120 inches in diameter.

3. Gearbox Service: Demonstrable experience in the service, repair, and/or replacement of large industrial gearboxes, equivalently sized as stated in Part 3.