Isolation Transformers

The engineering and design features of Equi=Tech isolation transformers are an ever evolving process.  Over the past 10 years and still going strong, there have been over fifteen revisions to the basic transformer design.  We are constantly striving to improve our products as more balanced power applications are studied and better understood.  We often hear from customers how well our products perform with spectacular results where others with similar products have failed.  We are meticulous and exacting with our designs and specifications.  We routinely provide superb customer support and our track record of success speaks for itself.

From the smallest 650VA toroid we offer to the largest 500kVA 3-phase E-frame model, every transformer is engineered and manufactured to the highest standards and most exacting specifications that have given Equi=Tech balanced isolation transformers a reputation for quality and superb performance among top professionals.  If there were a better way to make it, we would already be doing it.  Our proprietary transformer technology provides the most accurately balanced isolation transformers possible with today’s modern manufacturing methods.  Special winding designs and manufacturing procedures insure that every aspect of the secondary impedance is as perfectly balanced as possible.  This provides for minimal phase shift and as a result, the broadest possible bandwidth of common mode noise attenuation.  Some models have proprietary alloys used in the transformer’s magnet wire, some have a unique core composition.  This means that sensitive electronic signal processing equipment will operate with more clarity, greater definition and far fewer digital errors than ever before.  These are truly precision made instruments designed and built for today’s most sensitive electronics.

Every transformer is tested by the manufacturer well beyond its UL/CSA/CE listing requirements to insure many years of reliable service.  And, only Equi=Tech backs every system it sells with comprehensive technical support to insure the best results in any application.  No one has as much experience or understands balanced power transformers better than Equi=Tech “The Pioneer of Balanced Power”

Equi=Tech provides a full line of transformers, tested to the most rigorous standards, that convert commercial power into balanced technical power for both single- and three-phase locations.  There are three ways that Equi=Tech offers balanced technical power isolation transformers:

1.)  Toroid “Transformer in a Box” – wall mounted cabinet (Sizes range from 1 to 12.5 kVA).  A single-phase toroid transformer is mounted in a fan cooled (as required) NEMA 12 enclosure and terminated with heavy duty landing lugs for easy electrical hook-up.  These are by far the most efficient isolation transformers available today and include Equi=Tech’s state of the art balanced power transformer technology.  Like portable rack systems, an optional voltmeter and an input voltage selector switch is available for remote truck power systems or for monitoring and matching house voltage wherever put to use.

2.)  Single-phase dry-type transformers for large single-phase technical power systems (Sizes from 15 to 250 kVA).  The Equi=Tech “Spec Series” single-phase isolation transformers set the standard for precision-perfect output symmetry and balance.  15kVA transformers and larger are housed in a standard NEMA floor standing enclosure.

3.)  3-phase to 6-phase “wye” transformers for 3-phase systems (Sizes from 15 to 500 kVA) Equi=Tech’s revolutionary “Neptune Series” isolation transformers evenly distribute power from a typical 3-phase power source through three precision-balanced 120-volt output circuits.  Equi=Tech’s patented 3-phase to 6-phase “wye” design has gained the favor of top electrical engineers on technical power projects and is destined to become the industry standard for many years to come.  Here are some of the advantages of the “Neptune Series” transformers:

  • It is very easy to balance the single-phase load while using standard 3-phase commercial power distribution systems.  Our most recent NEC code addendum, now recognized as Article 647 in the 2002 NEC provides for recognized and accepted use of these transformers and the associated wiring methods.  For the purpose of maintaining high power factor and extremely low grounding noise in sensitive technical environments, use of these transformers may also be extended to include most commercial luminaires (such as fluorescent lighting systems) that have in the past been singled out as a prime source of much power distortion and noise as well as producing unacceptable levels of EMI/RFI.
  • There is a single grounding reference point for all three single phase outputs (the center tap) and there are no grounding currents present.  If all of the electronic equipment power supplies are balanced, all of the equipment chassis will be at unity potential.  Massive signal reference grounding systems are rarely required, even in the largest facilities.  Often this savings alone will cover the cost of the transformer and the improvements in noise levels and increased electronic equipment performance will be far more dramatic.
  • When the transformer is operated with a typical non-linear load, the direction of reactive currents created are opposite (with respect to ground) and equal in the balanced secondary windings of the transformer. Therefore the magnetic field generated by the reactive reactive currents cancels out as common mode information and remains isolated from the transformer’s primary circuit.  The outcome insures a higher power factor on the primary side of the transformer, unaffected by the non-linear load.  Neptune transformers are environmentally friendly in more ways than can be counted here.
  • Reactive current and noise is greatly reduced in a very large operation at minimal expense with upkeep cost kept to a bare minimum.  Typical problems associated with reactively loading a 3-phase system with various types of non-linear loads will literally become figments of an engineer’s fading memories.

The precision degree to which these transformers are balanced provides for the least amount of reactive phase shift possible which results in potentially a much broader bandwidth of common mode noise attenuation.  These high frequency harmonics otherwise tend to permeate an entire electrical grid which, aside from having a negative impact on sensitive electronics, are simply a waste of power.

As finer and finer resolution is demanded in todays modern digitial interfaces of all varieties, shapes and sizes, the need for refined balanced power technology will continue to grow.  Perhaps one day it might even become a mandatory requirement because of its environmental as well as its technical advantages.  Often, no other power conditioning device or active filtering system is required to maintain the cleanest possible active current wave form and a noise-free signal reference in any technical facility.  Sensitive electronic systems of all varieties perform more accurately and reliably.  The difference in equipment performance (as reported to us often) can be astonishing.

There is yet another major benefit use of these transformers provides, one that is perhaps even more impacting from a direct financial standpoint.  When reactive load current is cancelled in the manner described here, a higher power factor is maintained.  [kW2 + kVAR2 = kVA2] — (Where kVA => kW as kVAR => 0.)  As reactive currents are cancelled out when the system is under load, current and voltage will therefore remain in phase to a greater degree as more balanced power is applied to more impedance loads on the power grid.

Consequently, with a more phase coherent AC supply now available, all types of AC loads will use electricity more efficiently.  Stated in simple terms, for electrical power to perform any task, both current and voltage must be in phase to each other.  To the degree that they are not, nothing will happen.  To the degree that they are, an effect is achieved.  The bottom line and the major point to understand here is less kVA needs to be generated to perform a task when power remains phase coherent.  Higher power factor systemwide is a characteristic inherent to the balanced power architecture.  Furthermore, the more accurately balanced the system, greater efficiency will be realized.  This is one factor that should not be overlooked on a mass scale.

As has been described here, wide scale use of both Neptune and Spec series transformers across bulk utility power systems at the user level will provide increased power efficiency for everyone.  Less kVAR and high power factor is also more “gentle” on power generation and distribution systems which lowers maintenance and other related power distribution costs.  But perhaps most profound of all, reducing the need for utility companies to “compensate” for low power factor by producing more power to offset low efficiency will result in the savings of untold billions of dollars in fuel costs.

Among the many positive things one can say about Balanced AC, it is also environmentally friendly.


Use the following chart to specify Equi=Tech transformers by part number.  A sample part number is indicated in the heavy red outlined area.  The upper portion of the chart specifies Equi=Tech “Toroid” and “C-core” models.  The lower half specifies the higher capacity Equi=Tech balanced floor mounted dry-type distribution transformers.

Transformer Specifications

Click on a transformer size below for more information
Standard NEMA sizes are listed — for other sizes & voltage ratings consult with factory
“Spec Series” (1ø) – kVA

7.5 – 10 – 152537.550 – 75 – 100 – 167 – 250

“Neptune Series” (3ø) – kVA
openneptune neptunecabinet







15 – 304575112.5 – 150 – 225 – 300 – 500 – 750

Toroid “Transformer in a Box” – kVA
1.5 – 2 – 3 – 5 – 7.5 – 10 – 12.5 – 15 – 20

(Q-Type toroid transformers are offered ranging in size between 2 to 20 kVA)