Core Construction
HPS cores are manufactured from the highest quality non-aging, cold rolled, silicon
steel laminations. Cores are precision cut to close tolerances to eliminate burrs and
interleaved to improve performance. Full mitre stepped core construction is used for
our very high efficiency transformers.
Coil Construction
Coils are available in either aluminum or copper construction. Coils are precision
wound with continuous copper or aluminum conductors and are electrically balanced
to minimize axial short-circuit forces. The use of duct stick permits the flow of air, thus providing excellent cooling in addition to providing superior radial mechanical strength.
Insulation System
The insulation rating is the maximum allowable winding (hot spot) temperature of a
transformer operating at an ambient temperature of 40°C. Insulation systems are
classified by the temperature rating. HPS energy efficient distribution transformers
utilize superior insulation materials which meet or exceed UL standards. Higher
ambient temperatures and/or continuous overload characteristics can be achieved
with low temperature rise design.
Terminations
HPS transformers are provided (where applicable) with both high and low voltage
terminal lug connectors suitable for both copper and aluminum cables. These
connectors allow for easy field installation without the need to purchase connectors
separately, saving the installer both time and money.
Vacuum Pressure Impregnation (VPI)
Regardless of voltage class, our polyester resin impregnation system is preferred.
This material is a blend of a vinyl-toluene polyester resin and exhibits much higher
dielectric strength and bonding properties than most varnishes previously used, or
other encapsulations including oil modified epoxies. The VPI process ensures that
the insulating resin penetrates all voids completely, and provides a superior result
compared to simple dip and bake operations.
Testing
HPS has testing facilities in all manufacturing locations to ensure product quality.
These testing capabilities include: Heat Run, Ratio, Polarity, Partial Discharge,
Induced Voltage Test, Sound Level, Transformer Losses under linear and nonlinear
load conditions, Applied Power Frequency Voltage Test, EMF, BIL, Insulation
Resistance, Inductance and Resistance. HPS has a state-of-the-art test bench that
can test transformer efficiencies with non-linear load profile up to K-Factor 20.
