Dongan's 50 series industrial control transformers have been designed to the highest NEMA and industrial standards. The product features screw terminal connections, high regulation low temperature rise, a wide variety of voltage combinations up to 5000va in many cases. In addition, we do many specials in this same series. All copper windings.All designs are rated 50/60 Hertz.Rugged coil mounted screw terminals.Primary Fuse blocks and secondary fuse holders are available and are easily installed.Regulation characteristics equal or exceed the highest industry standards.Transformers .750 kVA and below employ a UL Class 105C insulation system with 55Ctemperature rise at a maximum ambient of 40C.Transformers 1.0 kVA and above are designed with a UL Class 180C insulation system with 115C temperature rise at a maximum ambient of 40C.