The headquarters for our corporation is located a few miles away from the picturesque Blue Ridge Parkway in Roanoke, VA. Designed and constructed specifically to produce power transformers, the 145,000-square-foot manufacturing facility is state-of-the-art.
In December 2013, a new facility was developed 11 miles from the main plant in Troutville, where the tank fabrication, sandblasting, and paint process were relocated. The tank fabrication plant is equipped with a welding robot that delivers leak-free welds, downdraft sandblasting booth for safety, and an SP-10 finish per SSPC standards for premium paint adhesion. The paint system is an epoxy primer on an activated surface and a top coat of polyurethane baked to a hard finish to prevent rusting. The plasma table has been fitted with an etching gun to mark the location of all accessories, thus eliminating missed parts. The cross ventilation keeps the air free of weld fumes for the safety of personnel. The tank walls are aligned with a laser to ensure uniform clearance of the coils from the tank wall. Dye penetrant and magnetic-particle-leak-checking technologies are used for quality assurance.
All tank fabrication facilities were equipped with these improvements in 2013. The combined capacity of all plants is more than 1500 tanks per year. The teams are proud to work in a clean and safe factory with a Mod Factor of 0.9 – better than the industry standard.
The vapor phase drying (VPD) system was installed in 2015 at Roanoke to achieve optimum insulation dryness.
The VPD system is automated; technicians can download the process parameters to their cell phones. It allows for two transformers to be processed simultaneously and achieves a vacuum level of .25 torr.
A second core-cutting machine was installed in 2015 to increase capacity and eliminate the possibility of a single point of failure. The machine cuts a 26-inch-wide core; the edge burr level is typically less than 20 microns. This cutting process decreases power and eddy loss while also reducing sound level by 2 dB.
The core and coil assembly are laser-aligned to ensure uniform clearance from the coils on the tank wall. The DETC is also aligned using laser to guarantee smooth shaft rotation and minimal contact resistance.
All floors of the plant were ground and sealed in 2015 to eliminate floor dust. Four winding machines were added to increase the capacity to build larger coils. The plant is equipped to manufacture 30 MVA base rating, 161 kV, 650 kV BIL as well as manufacturing dry type to 10 MVA, 35 kV, 150 kV BIL.
A second test bay was added in 2015, allowing two units to test simultaneously. The impulse test capacity was increased to offer Switching Wave Impulse Testing.
The net results of the improvements are:
- Reduced PD level below 300 PC; reduced sound level below NEMA standard for quiet operation and long life. No rusting and defect-free units delivered to the site for trouble-free installation. The Roanoke plant achieved 100% pass rate 5 out of last 6 months. It is recorded in Medium Power Transformer Manufacturing.
- Check out the Manufacturing section for further equipment details.
- Call Plant Manager, Tim Smith OR Technical Manager, Parminder Panesar for additional information. Matt Gregg is VP of Operations over this plant.
- A core-building station with hydraulic lift was commissioned in 2019 to ensure minimum core handling and reduced losses.