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HOW IS E-RATED EFFICIENCY ACHIEVED ?
To reduce
magnetizing
losses and
load
losses, under
‘real world’ non-linear load conditions, the design of core and
coils requires significant refinement. The
e-Rated
Transformer
Engineering Program™
is used to
optimize the transformer’s losses under
linear
and any
non-linear
load condition.
Conventional Core & Coil Design
Figure 1
e-RatedÒ
Core & Coil Design
Figure
2
With reference
to Figures 1 & 2, an examination of a conventional
transformer and an
e-RatedÒ
transformer will reveal several obvious differences in both the core
and coils.
Figure
3
A
conventional transformer’s butt lap cut core, as shown in
Figure 3, consists of rectangular sheets of core steel arranged
in such a way that the grain orientation of the steel is along the
flux path, except in the corners
where the flux path changes
direction from the legs to the yoke members.
Figure 4
As an alternative, a scrap-less
miter-cut core, as shown in Figure 4, has pieces of core
steel that are cut at 45°
angles and arranged such that the grain orientation is maintained in
line with the flux path, even in the corners of the core. This
design reduces core loss.
Figure
5
As a further improvement, the
e-RatedÒ
transformer’s
full
and step lap miter cut core,
as shown in Figure 5,
ensures that the overlapping of the joints in the corners are
mitered and staggered so that the best possible grain orientation
and flux transition is achieved.
On close examination of Figures 1 & 2, it is also obvious
that there are significantly fewer laminations in each group of
sheets in the full and step lap miter cut core than in the
butt lap cut core. By avoiding crowding of the flux lines at the
corners, the lowest core losses and best efficiency is achieved.
In addition, core and winding materials, and geometry have been
refined to achieve minimum losses under all loading conditions.
These design changes require sophisticated engineering ‘know-how’
and advanced manufacturing methods. |
