Remanufactured & Refurbished Transformers

RESA Power offers sales and installation of refurbished and remanufactured transformers providing the same performance as original equipment manufacturers new transformers, but at a much lower cost-effective price. On average, our remanufactured transformers are 60% to 70% the cost of a new unit.

RESA Power Service’s remanufacturing program offers quick turnarounds at fantastic prices. Our transformer lead times and deliver schedules are custom fit to your specific needs and site requirements; often beating lead times from the factories by weeks or months.

careers team work icon

Search our Inventory

RESA Power is an established supply leader known for providing high quality components assisting clients with life extension of electrical equipment at a reasonable price. Click view products online to view our large inventory of electrical equipment now or at your convenience. You can also request a quote from RESA Power directly and speak with a professional consultant in our sales team that will gladly help you find that elusive piece of equipment to fit your specific needs! Our high-quality products come from a wide variety of recognizable major manufacturers. That same brand recognition will give your clients piece of mind knowing that RESA qualified technicians have restored it to its original equipment manufacturer’s specifications.

line chart numbers increasing icon

Remanufacturing Program Overview

Transformers go through a rigorous process to ensure the equipment is high quality and performs its design functions safely. RESA Power Service revitalizes transformers quickly, offering sustainability for your employees. The decreased delivery times means you won’t have to wait long for a completely rebuilt pre-owned transformer. Reduce, reuse, recycle!

white check mark icon


Our reliable remanufacturing service includes:

  • Electrical testing per IEEE and NETA standards (such as transformer turns ratio (TTR), insulation resistance, winding resistance, power factor, excitation, and over potential – Hi Pot) is performed on equipment prior to cleaning or maintenance work as a baseline report.
  • Top cover and insulating fluid are removed.
  • Internal inspection is conducted to provide an assessment of the condition of the equipment.
  • Busing is cleaned and removed.
  • Gaskets are replaced on all components.
  • Bushings are cleaned, inspected and paddles are re-tinned
  • Windings are inspected, cleaned, and flushed.
  • All electrical connections are verified mechanically and via resistance testing.
  • Insulating fluids are either reclaimed or replaced and vacuum backfilled into the tank.
  • Top cover is reinstalled.
  • 24-hour pressure testing is performed at 5-6 psi (not to exceed tank rating).

  • Paint prepping is executed including sanding, body work, and rust removal.
  • All transformers are painted with a urethane or epoxy two-part topcoat.

Our four distribution and manufacturing centers across the United States provide high-quality service and support to every major metropolitan area.

careers team work icon


All of RESA Power’s Service professionals conduct electrical tests following the standards of NETA, the worldwide expert in electrical power systems and equipment assessment. All equipment is fully tested and warranted.

Electrical Tests Include:

  • Insulation Resistance Test is direct current (DC) test and one of the oldest methods in use today for determining the dielectric strength and moisture content of solid insulation by measuring leakage current (loss current).
    • Polarization Index – When moisture is present in solid insulation the PI will be lower indicating a more deteriorated condition. A ratio of 2.0 is desirable, 1.0 to 2.0 are marginal with values closer to 1.0 being considered poor. typical ratio of is used to indicate motor insulation health and identity accumulation of contaminants and any physical
    • Dielectric Absorption Test – Good insulation will have insulation resistance values that steadily increase as time increases. The Dielectric Absorption Ratio is the 30 second insulation resistance value divided into the 60 second value. The ratio will indicate if indeed the resistance increases over time and if the increase is indicative of good insulation. The same grading of insulation applies to the DAR as to the PI
  • Winding Resistance: this DC test is used to assure that all circuits are wired properly, connections are tight, and as a base for assessing possible damage. In a 3-phase application each phase’s winding resistance measurement is compared to the other 2 phases. Each phase should be in balance with the other 2 phases and should gradually increase or decrease as tap positions are raised or lowered
  • Transformer Turns Ratio: this ratio assures there are no open connections, no shorted or open turns in the windings, incorrect polarity connections, and verify voltage ratio of the transformer in each tap.
  • Power Factor Insulation Test: this maintenance test is similar to insulation resistance testing as it too measures leakage or internal losses but does so with alternating current (AC) and encompasses both solid and liquid insulation by determining the power loss in the insulation This is accomplished by comparing the proportion of power used to the total product of the applied voltage and current as a percentage. Preferred power factors of new or properly dried transformers should be measured and used as a base line for future readings to determine if the internal losses are increasing indicating a deteriorating insulation system.
  • Excitation Test: this AC test checks for abnormal core Conditions such as deterioration of the insulation layers at the core laminations, loose core clamps, multiple core grounds, shorts from the core to the tank, disarrangement or lamination slippage are measured as core losses and compared to original factory test results. Note: on 3 phase transformers the excitation current is typically similar for two phases but notably less for the third phase which is wound on the center leg of the core assembly.
  • Over Potential Testing (Hi Pot): this test (AC or DC) stresses the solid insulation in a transformer by applying higher voltage to the transformer’s windings than their ratings. The voltage applied is dictated by the level of testing desired, the type of current (AC/DC) and capacity of the test equipment. There are 3 levels of Hi Pot testing: Factory, Acceptance and Maintenance levels as described in NETA and IEEE publications. Voltage is applied in steps until the desired voltage is value is achieved. Leakage current is monitored until and while the desired test voltage is achieved. The voltage level is held for a maximum of 1 minute and then gradually decreased to zero.
  • Auxiliary and Functional Checks: will ensure that the instrumentation and accessories are in proper working order and function as desired (fans, gauges, switches, and relays)

Distribution & Power Transformers

RESA Power’s specialties are not limited to selling power transformers! We are transformer experts offering service and maintenance after the sale, too! Special services include refurbishing, rebuilding, and repairing transformers; oil servicing, purification, and reclamation; painting/shot blasting; testing; and customizing to your needs in this dynamic industry. Services and maintenance are unlimited and include step voltage regulators, reclosers, switches, breakers, and capacitors.

With the advent of Western Utilities Transformer Service, a RESA Power company, our transformer services team has provided electrical solutions to thousands of companies throughout the United States and Canada for over 35 years. Since 1985 we have provided quality services and repair of electrical apparatus and systems with a commitment to detail and customer satisfaction. This commitment to quality and service has fostered the development of strong relationships with both domestic and foreign leading manufacturers of electrical power and distribution equipment.

Western Utilities Transformer Service is a complete service center and original equipment manufacturers’ warranty service centrally located in central California. The service center is supported by factory trained service technicians, NETA certified testing centers, insulating fluids laboratory and component distribution centers throughout the state and the continent. Our combined efforts of providing support to the OEM’s for warranty repairs, installations and startups for the contractors and ongoing repairs and maintenance to the end-users has established RESA as the “go to source” for all of your power needs.

Pole Mount, Pad Mount, and Substation-Style Transformers

RESA Power has a wide variety of offerings to fill your transformer requirements. Pad mounted, pole mounted, vault or substation styles of transformers and related equipment are included in the array of equipment sold and serviced by RESA Power. Moreover, our Service Center provides expert in-shop testing, modernization, and upgrade services for transformers and other substation equipment. We provide 24/7 emergency services for most domestic and foreign OEM products, liquid filled or dry, substation type or pad mounted, power or distribution, pole mounted or underground transformers and electrical equipment.

1, 2, and 3-Year Warranties Available

RESA Power offers warranties that cover products sold for either one, two, or three years. See our terms of sale for warranty details as needed.

Reduce your installation lead time with our reliable remanufactured transformers. Save time and money by contacting RESA Power today!