API Services Helps Voith Hydro Update Denison Dam Hydro Stator

MSP Provides Accurate Reference Data and Verification Throughout Yearlong Assembly Process

Dams are one of the marvels of 20th Century Engineering. They are monolithic structures that re-shape landscapes, protect communities from floodwaters, and produce more than 10% of the electricity used in America. And while the outer facades are largely unchanging, the internal components of dams (especially ones that produce electricity) need regular maintenance and renovation of old parts. When Voith Hydro was contacted to rebuild the bearing housing and rotor assembly of a Hydro Stator for Denison Dam in TX, they enlisted API Services to assist with the “as found” measurements. Throughout the yearlong assembly process, API Services was able to:

· Install a Local Coordinate System to allow accurate component transformation and installation

· Ensure accuracies within +\- .005” upon final assembly

· Communicate offsite machining data with onsite alignment measurements

Located on the Red River that separates Oklahoma from Texas, Denison Dam has stood 165 feet high, and over 15,000 feet long, since 1943. In addition to being a major floodwater control, the dam produces nearly 250,000 megawatt hours of electricity every year. In order to produce this kind of electricity, the Hydro Stator must be maintained and eventually replaced over time. Typically, the bearing housing and full rotor assembly on these parts is rebuilt every 35 years, but when Voith Hydro was brought in to perform this overhaul, the original Stator was still in use 75 years later.

Voith Hydro is part of the Voith Group and a leading full-line supplier as well as trusted partner for equipping hydropower plants. Its portfolio of products and services covers the entire life cycle and all major components for large and small hydro plants, from generators, turbines, pumps and automation systems, right through to spare parts, maintenance and training services, and digital solutions for intelligent hydropower. Voith turbines and generators produce one-third of all hydroelectric power in the world.

Voith Hydro Site Manager Lalit Adhikari was assigned to the Denison rebuild, and he knew he would need a solution to define the “as found” positions of the Hydro Stator and its lower bearing housing components. In order to machine best fit parts that could be used in the existing Stator structure, Voith would have to define all of the values present. And for those measurements, Lalit called in the expert team of metrologists at API Services.

API Services analyzed the setup at Denison and proposed utilizing the portability and accuracy of the Radian Laser Tracker to define the “as found” stator position and give the true centerline. These values would ensure the bearing housing and rotor assembly are set cylindrically in position and at the correct elevations to each other.

The Services team came in for this initial survey approximately 1 year prior to the component installation. They were able to install a local coordinate system, which allowed best fit transformations at the machine sites compared to measurement data rather than time-consuming on-site comparisons and rework. The coordinate system also gave Voith the ability to install components very accurately to each other during the yearlong assembly process. All bearing assembly component positions and elevations were surveyed to set baseline locations for the new components.

As Voith installed each component, the centerline location was measured and reported through the entire process. Because the assembly process was aligned and checked at every step, the final measurement result was a cylindrical alignment of approximately 5 large Rotor and Bearing Assembly components all within +\- .005” of the Upper Stator Housing Centerline. All Elevation and Component Collision Gaps were well within allowable limits. API Services’ process helped ensure offsite machining and onsite Laser Tracker Alignment could be combined in a seamless installation, saving costly downtime and rework.

Voith found that API Services’ team and equipment added so much value that they have invited the API Services team to present solutions for other elements of the next Rotor Assembly onsite at Dennison Dam. In addition to the “as found” measurements and analysis that API Services performed, they are offering solution for machining aspects of additional projects, Positional Setting and Leveling of Milling Machinery to name a few.

API Services’ initial “as found” measurements and routine centerline checks saved Voith Hydro time and costly rework throughout a yearlong assembly process. The team at API services offers an unmatched combination of metrologists with application experience in every industry and state-of-the-art OEM dimensional metrology products. They are standing by to assist your needs worldwide.