Wm. F. McGraw & Co., located in Riverview, MI, specializes in engineered materials with high-performance characteristics that increase the durability, safety, and efficiency of generator systems. Whether your need is insulation, support, or protection, all of our components are made to meet the most demanding specifications. Whether you have turbo generators, hydro, or diesel gas, we provide OEMs and service providers with mission-critical materials that operate under extreme thermal, electrical, and mechanical stress.
We have advanced material technologies that enhance the performance of generators across industries. Each class of material is selected and made for specific functions that enhance reliability, safety, and longevity.
Composite Materials
We fabricate composite materials that provide optimal electrical insulation and structural support. These materials are unique in providing support to rotor and stator assemblies by maintaining alignment and managing mechanical fatigue. Their characteristic of withstanding high heat and severe degrees of hot and cold allows for consistent reliability over extended operational loads. Each component is CNC machined to strict standards, creating tight tolerances and a perfect fit within the design of the generator systems, essential for a long life, especially when subjected to high thermal and mechanical stress.
Thermoplastics
Helm combined thermoplastic components are well-suited for lightweight applications with strict limits on heat exposure/degradation and size constraints for maintaining dimensional stability. We produce insulating blocks, covers, and spacers that withstand sustained exposures to thermal aging. Given that they are non-conductive, they can be safely installed to enclose live components. The materials are also resistant to moisture and chemicals, which are fundamental in harsh generator environments. The flexibility of these materials in their applications and machinability as a platform allows them to be used in focused and compact generator designs, providing additional efficiency while limiting costs without sacrificing insulation or strength in high-heat exposure applications.
We manufacture materials and components specifically designed to address the particular needs of different types of generators. Each type has its own insulation, vibration, arc, and thermal requirements, and we manufacture to serve those needs.
Turbo Generators
Turbo generators experience extremely high temperatures and mechanical load, and are mostly found in utility power stations or industrial operations where efficiency and uptime are paramount. We manufacture composite insulation materials that retain their form and suitability even in rapidly changing high-temperature zones. Our custom slot liners protect and hold the windings in the stator core, and phase-barriers and stator wedges, to specified tolerances without air gaps and minimizing potential vibration-induced damage. These materials will not deform, crack, or undergo dielectric breakdown, and keep the generator operating in the harshest conditions, increasing the life of the equipment.
Hydro Generators
Moisture is the biggest enemy in hydroelectric systems, necessitating the need for moisture-resistant insulation and dielectric arc barriers for long-term reliability. We manufacture custom machined bushings and support tubes made from non-hygroscopic composites, providing no water absorption or tracking. There are insulating supports that maintain electrical separation and resist corrosion in continuously humid or submerged conditions. A proper design allows for precise fit and hold, without excessive tension or compression of insulation or components during load cycles. Our mechanical features will also minimize arc flash risk while enabling hydroelectric systems to remain safe and efficiently operational in wet environments.
Diesel and Gas Engine Generators
Diesel and gas engine generators are typically found in mission-critical backup systems or mobile power units, where electrical insulation, as well as toughness and ruggedness, must be considered. We manufacture arc-resistant insulating panels and covers that protect critical connections from electrical discharge and mechanical shock. In addition, we provide custom spacers and standoffs from rod and tube stock for electrical insulation, heat dissipation, and support of components in a condensed and vibrating environment. The generation of power in diesel generators is typically forged in oil and fuel exposure, and with temperature cycling, so we choose materials that will resist these conditions, allowing them to reliably perform for projects in medical, actual construction, military, and emergency needs.
We fabricate a wide range of components essential to generator performance and safety. Our materials are carefully selected and processed to withstand arcing, thermal cycling, vibration, and mechanical stress, ensuring both safety and longevity in demanding environments.
Our insulating bushings are precision-machined from high-dielectric tubing to maintain electrical separation between conductors. These bushings serve a vital role in preventing tracking and flashover between phases, especially in high-voltage environments. Designed to fit seamlessly within generator housings, they maintain consistent performance over time despite exposure to elevated temperatures and continuous electrical load. Their dimensional integrity ensures a reliable fit, which contributes to system stability and reduces the risk of insulation failure.
Rotor and stator spacers are fabricated from robust composite rods and serve a dual purpose: maintaining proper air gap and providing rigid mechanical support. These spacers resist deformation under high torque and thermal expansion, making them ideal for use in rotating electrical machines. Their exact tolerances support balanced rotor movement, minimize energy loss, and help preserve generator efficiency. Whether used in high-speed turbines or stationary power generators, these spacers enhance structural integrity and insulation reliability.
Slot wedges and liners are crafted from thermally stable insulating sheets and play a crucial role in securing windings within stator slots. Wedges are cut to lock the coils in place under vibration and magnetic force, while liners serve as a dielectric buffer to prevent shorts. These parts are knife-cut or die-cut for a clean finish and tailored to tight specifications to reduce movement and degradation over time. Their function is essential for maintaining electrical clearance and long-term generator performance.
Phase barriers and end caps are critical in controlling electrical flow and minimizing arcing at termination points. Designed for custom fit, they are cut and formed from arc-resistant materials that provide robust separation between energized sections. These components not only prevent unintended contact and discharge but also offer mechanical support that simplifies assembly and improves system reliability. Whether used in compact or large-scale generator setups, they enhance the overall safety and durability of the system.
We bring decades of expertise to every generator insulation solution. Our materials are rigorously tested for arc resistance, electrical insulation, and thermal stability. Whether you need custom spacers, barriers, or bushings, we deliver fast turnaround with high-quality precision. Every part is engineered to meet demanding generator applications, ensuring long service life and dependable performance. Partner with us for material reliability that powers performance.
Let Wm. F. McGraw & Co. help bring your generator system to life with materials engineered for safety, endurance, and electrical integrity. Located in Rivervie, MI, we support OEMs and service teams with fast, reliable custom fabrication. Contact us today for expert consultation or a quote on your next generator insulation or support project.
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