Preformed Windings Ltd are a high-quality manufacturer of HV diamond coils based in England. As an independent manufacturer, Preformed Windings are uniquely positioned to partner with OEM’s and service companies to offer world class product and technical support. Preformed Windings diamond coils have been used in thousands of HV motor and hydro generator rewinds all over North America as well as globally and we are trusted partners to repair companies and end users alike.
As specialists in coil manufacturing for over 50 years we work with our customers and end users to optimize coil design and in many cases, coils can be manufactured to not only replace existing coils but upgrade them. This can result in greater efficiency and significant increases in output which is proving very popular as the demand for renewable energy increases and a large proportion of the installed base approaches the age of major service requirements. Our range of HV coils includes coils with the lowest partial discharge available which are designed to work for decades. Additionally, ‘QualCoil H’, the first resin rich coil specification suitable for class H applications which has passed rigorous testing such as Voltage Endurance (VE) and Thermal Cycle (TC) testing, with the coils successfully passing 2,000 hours on VE test.