Patent ID: 7907039
Filing Date: 2011-03-15
Classification: H01F

Abstract:
1. An improved compact dry transformer comprising a magnetic material core and a coil assembly assembled onto the core, the core comprising heat dissipating covers with cooling fins snug fitted over the core, the covers being made of non-magnetic material having good thermal conductivity, the coil assembly comprising a low voltage winding and a high voltage winding with electric insulation layers between the layers of conductors of each of the windings and between the windings, the coil assembly being mounted on the core over a heat dissipating inner jacket made of non-magnetic material having good thermal conductivity in close contact with the inner jacket, the inner jacket having a slit along the length thereof, at least one first heat pipe located between the core and inner jacket in close contact therewith, the first heat pipe protruding out of the coil assembly and being provided with cooling fins at the protruding thereof, the coil assembly further comprising a heat dissipating outer jacket made of non-magnetic material having good thermal conductivity snug fitted over the high voltage winding, the outer jacket being provided with a slit along the length thereof, at least one second heat pipe located against the outer jacket in close contact therewith, the coil assembly with the outer jacket and second heat pipe being encapsulated with a resin casting with the second heat pipe protruding out of bushings cast with the resin casting, the protruding outer end of the second heat pipe being isolated from the ground potential by the bushings and provided with cooling fins, the terminals of the transformer being located in the bushings and connected to the windings ends.