The picture below is a 3-phase 25kVA -415/415V, with taps on the output winding. This 3 phase transformer is built using 3 single phase toroid transformers.
A 3 phase transformer designed in this format has all the features of running 3 phase load with some added benefits.
- A normal 3 phase transformer would be much bigger and heavier in size as compared to this design (compact). Mounting 3 toroids horizontally, stacked on top of each other would generate higher thermal runaway parameter.
- The air pockets placed on the top, gives this design a good thermal convection. The cooling characteristics on this design are better than a conventional 3 phase transformer design due to additional air flow paths.
- Toroids placed vertically besides each other with space for air flow helps dissipate heat and prevent losses. A typical core loss in a conventional 3 phase transformer ranges between 1-1.2 watts/kg. The core loss measured in this design is lower than 0.8watts/kg. The design also has low core magnetostriction (core noise during operation)
- The external flux leakage is comparatively low due to close coupling of the primary and secondary winding.
- The application of a full faraday shield between the primary and secondary winding produces a superior capacitor coupling of input noise.