Technology Benefits
The 3D distribution transformer with the revolutionary delta (3D) wound core is the ideal “green” transformer:
- Increased electricity savings, lower Total Owning Cost (TOC) and reduced CO2 emissions (in SILVER and GOLD energy saving models)
- More robust and durable
- Quieter
- Promotes better stability in electrical network
Technology History
In 1880, a European engineer and inventor theorized that the optimal three-phase transformer should have a symmetrical delta-shaped (3D) core. However, his theories could not be transformed into reality because there was no manufacturing technology available at the time that could make it commercially viable.
Technology Introduction
The core: 3D wound core
The active part: 3D wound core + coil winding
The transformer: 3D energy saving oil-immersed hermetically sealed distribution transformer (outdoor installation)
- The 3D transformer has been commercially available in Europe since 2004 and is billed as the “transformers of the future”
- Thai Maxwell Electric (TME) began its 3D transformer development program in 2008 and is the first manufacturer in ASEAN to introduce the 3D energy saving oil-immersed distribution transformer in 2012
- The innovative 3D wound core can only be manufactured using the latest wound core technology (TME has employed similar wound core technology since 1979)
The revolutionary 3D wound core
The conventional stacked core
Technology Highlights
Better core construction
3D wound core – Single wound core ring with one-turn cut manufactured using automatic core slitting / winding / cutting machine (only 1 joint and much lower air gaps present results in low stray magnetic loss). 3 identical core rings are combined to make a 3 phase core.
Stacked core – Comprises of 3 core limbs & 2 yokes assembled together to make a complete 3 phase core (numerous number of joints and air gaps present results in higher stray magnetic loss).
3D wound core – Each core ring limb resembles a semi-circle allowing 2 core ring limbs of equal cross section to combine to make a core limb. Cross section of core limbs takes closer shape of a circle, with a higher filling factor of approx. 98% resulting in magnetic flux being almost fully utilized.
Stacked core – Cross section of core limbs are stacked type, with a lower filling factor of approx. 93% resulting in magnetic flux not being fully utilized.
Better core construction
3D wound core – Core limbs are in symmetrical delta shape (symmetrical 3 phase magnetic circuit) resulting in optimized magnetic flux distribution.
Stacked core – Core limbs are not in symmetry (non-symmetrical 3 phase magnetic circuit) resulting in under optimized magnetic flux distribution.
3D wound core – The different magnetic path directions (red arrow) of both core ring limbs that make a core limb combine to achieve zero vector sum for the magnetic flux (green arrow), resulting in magnetic flux being balanced in each phase. Magnetic path of 3 phases are of equal distance (red arrows), resulting in 3 phases having better balanced magnetic circuits and reduced exciting currents.
Stacked core – The stacked core design is unable to achieve zero vector sum for magnetic flux, hence magnetic flux is distorted in the direction of silicon steel resulting in magnetic flux not being fully utilized.
Magnetic path of 3 phases are of unequal distance (red arrows – magnetic path A and C are longer than magnetic path B), resulting in 3 phases having unbalanced magnetic circuits and higher exciting currents.
