A Division of Transfactor Industries Inc. Concord, Ontario, Canada

A GUIDE ON HOW TO COMPARE TRANSFORMERS FOR MAXIMUM VALUE

How quickly will an ultra high efficiency unit pay for itself? How much more should you be willing to pay for such a unit? The transformer’s payback is simply a function of loading on the transformer, and cost of the electricity. Increasing either will result in sooner payback. A study on Rex 3-phase copper distribution trans-formers across a broad range of kVAs revealed the following*: *Using a sample of 45, 225, and 500 kVA transformers, assumed electrical cost of $0.10 / kWh

In nearly all cases, a Z2 design will pay for the difference in price in less than 2 years! Depending on loading or increased electrical cost, payback on Z3 transformers is also within 2 years.

Existing energy efficiency legislation has defined mini-mum performance standards for transformers. In the past, transformers have been considered an unavoidable contributor to the total energy losses of a system, be-cause the added material and labour costs associated with higher efficiency levels were not justifiable by sav-ings in electricity costs. Today, advances in transformer core materials, improved design methodologies, and enhanced manufacturing techniques have changed all that. With the rising costs of electricity, units that achieve higher-than-legislated efficiency levels can certainly re-duce total ownership costs by minimizing the operating costs of electrical systems.

Even when the load connected to a transformer is off, the power needed to keep the transformer energized con-sumes electricity (core losses). When the loading is in-creased, the resistance of the conductors in the windings begin to contribute and becomes the primary source of loss (load losses).

Rex Transformers utilize cutting edge materials and superior construction methods to achieve ultra-high efficiency levels. Lower flux densities, advanced mod-eling techniques, and manufacturing control tech-niques allow for cooler operation. As a further bene-fit of this approach, Rex transformers gain overload capability and short circuit withstand strength. The following core construction methods are instrumental for achieving the sought-after performance:

Butt-Lap Cut Core: Rectangular strips of high grade grain oriented silicon steel arranged to minimize core reluctance to flux.

Mitre or Step-Lap Mitre Cut Core: Mitre cuts at cor-ners reduces flux crowding aiding in efficiency. Step overlapping further reduces losses at transition spots.

UnicoreTM Distributed Gap Core: A highly specialized machine precisely bends core steel to a shape that gives the flux a continuous path, maximizing the grain orientation of the steel.

Download our free efficiency comparator tool. The Rex Power Magnetics website features a free efficiency cal-culation tool that helps analyze the economic payback for your specific application, taking into account the cost of electricity and the percentage-loading. Also, it can help you fine tune the core (no-load) and load-losses you may want to specify to our engineering department. Enter competitors’ loss and cost data to compare to Rex designs! Use the tool to arrive at your ideal tradeoff for efficiency. Available at: www.rexpowermagnetics.com

Z2 vs Z Z3 vs Z 35% loading 1.97 years 3.40 years

70% loading 1.48 years 1.38 years

Does it pay back?

Understanding transformer losses

How does a Green Line transformer reduce losses?

SIN

GLE

PHA

SE

THRE

E PH

ASE

This is the legislated efficiency standard in Canada and USA (NEMA TP-1 & CSA C802.2), which took ef-fect in 2010. For transformers intended for sale in the US, there will be a new standard in 2016 (see three star standard, below).

Green Line Energy Efficient Transformer Meets or exceeds NEMA TP-1 & CSA C802.2 (CSL-1) 2010 efficiency requirements

Green Line Premium transformers are at an interme-diate level of efficiency, between the 2010 standard and the 2016 levels. For most customers, these very efficient units are an economically wise choice which offer payback in electricity savings.

Green Line Premium Energy Efficient Transformer Meets or exceeds DOE “CSL-2” efficiency guidelines

Green Line Ultra-Premium transformers are the cut-ting edge in design and materials, which result in ex-tremely low core and load losses. As of January 1st, 2016, this will be the minimum efficiency level for transformers for sale in the USA

Green Line Ultra Premium Energy Efficient Transformer Meets or exceeds US DOE 2016 Efficiency (DOE 10 CFR Part 431, released 2013)

There are three options for the efficiency level, which are explained to the right. Your selection will be indicated in the final suffix in the part num-ber ordered (Shown as blanks, in the table below).

For single phase transformers, there is only one currently legislated minimum efficiency which will remain unchanged even after 2016. Use suffix ‘Z’.

For special efficiencies, use ’X’ and specify the effi-ciency.

Efficiency is reported at 35% load, 75 °C rise, with unity power factor

B C 300 J - M S1 / ... / Z2 E3R / /

Base Catalog Number and options - see our distribution transformer catalog to assemble

your correct part number

EXAMPLE REX CAT #

KVA

BC15J-M/__ 15 BC30J-M/__ 30 BC45J-M/__ 45 BC75J-M/__ 75 BC112J-M/__ 112.5 BC150J-M/__ 150 BC225J-M/__ 225 BC300J-M/__ 300 BC500J-M/__ 500 BC750J-M/__ 750

SC15J-K/__ 15 SC25J-K/__ 25 SC37J-K/__ 37.5 SC50J-K/__ 50 SC75J-K/__ 75 SC100J-K/__ 100 SC167J-K/__ 167 SC250J-K/__ 250 SC333J-K/__ 333

‘Z’ 2010 level

‘Z2’ Premium

‘Z3’ Ultra Premium

97.00% 97.50% 97.89% 97.50% 97.90% 98.23% 97.70% 98.10% 98.40% 98.00% 98.33% 98.60% 98.20% 98.49% 98.74% 98.30% 98.60% 98.83% 98.50% 98.73% 98.94% 98.60% 98.82% 99.02% 98.70% 98.96% 99.14% 98.80% 99.07% 99.23%

97.70% 98.00% 98.20% 98.30% 98.50% 98.60% 98.70% 98.80% 98.90%

There remain two other commonly specified efficiency levels: The NEMA Premium level, and the CSL-3 (DOE 2010) efficiency level. Rex can pro-duce to these lev-els or any other custom specified efficiency level. Use suffix “X” in the part number and detail your re-quirements on the Purchase Order.

98.39% 98.23% 98.60% 98.44% 98.74% 98.59% 98.81% 98.69% 98.95% 98.81% 99.02% 98.90% 99.09% 99.03% 99.16% 99.12% 99.23% 99.18%

Specifying the right Rex distribution transformer is easy!

‘ZNP’ NEMA Premium

levels

‘ZCSL3’ DOE CSL-3

levels

97.90% 97.97% 98.25% 98.29% 98.39% 98.46% 98.60% 98.64% 98.74% 98.77% 98.81% 98.86% 98.95% 98.97% 99.02% 99.04% 99.09% 99.16% 99.16% 99.17%

Our distribution catalog helps form the correct part number based on conductor material, pri-mary and secondary volt-ages, and various options. The final suffix of the part number denotes the efficiency level.

‘Z’

‘Z2’

‘Z3’

CAT DATE: 11/13

Contact and Sales info: Tel 905.695.8844 or Fax 905.695.8855 TOLL FREE USA/CANADA 1-800-387-2840 E-mail: sales@rexpowermagnetics.com 65 Basaltic Rd., Concord, ON, L4K 1G4

Contains up to date information on: Drawings and engineering specifications Selection and efficiency calculation tools Ordering information Warranty and terms & conditions

Our 145 000 sq. ft. design, manufacturing, and customer service facility in Concord, Ontario

OUR FULL PRODUCT RANGE: Power Transformers (Up to 15 MVA — 35 000 V) Cast Coil, VPE and VPI Construction Substation Type complete with primary disconnects Traction Power, Rectifier, Crane duty, Special Regulation, Service station distribution Specialty Type and Special Voltage Transformers K-Rated, Electrostatically shielded Ultra Isolating Multiple Shielded Harmonic Mitigating Electromagnetic Field Shielded Epoxy Potted, Hazardous location Marine duty types (with applicable certificates) Mini Power Centres High Efficiency and Ultra High Efficiency On line Tap switching and Auto Voltage Regulating units Hazardous-Location Transformers (Class 1, Div 2) Control & Machine Tool Transformers (50 VA to 7500 VA) Enclosed, open style, or potted DIN rail mountable units

General Purpose Transformers Distribution/Isolation, CE marked transformers Autotransformers Drive Isolation Motor Starting Reactors Input and Output reactors Motor guarding transient filters DC chokes, Saturable-core reactors Inter-bridge reactors High Voltage Iron Core or Air Core Reactors Enclosures NEMA -1, -2, -3R, -4, -4x, -12 Stainless Steel and Special Paint Custom switchgear and specialty industrial enclosures Switchgear Components Low and High voltage standoffs and insulators Surge (lightning) Arresters Transformer Testing, Refurbishment, and Repair Replacement of windings, core, insulation, etc.

View or download all of our product catalogs and brochures from our website: www.rexpowermagnetics.com