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High Rise Transformer


For nearly 5 decades, MGM Transformer has specialized in Medium Voltage Dry Substation Transformer design and production. MGM Transformer private labels for many of the most demanding multi-national OEMs in addition to providing its own branding offering.  

MGM Transformer’s standard designs cover the full range or requirements from 5kV to 34.5kV and from 500kVA to 10,000 kVA.  As an engineering-oriented company we are able to design the high voltage/low voltage switchgear interface to assure the proper match in the field. As required, MGM Transformer can offer non-standard substation designs for special situations such as failed unit retrofitting or PCB replacement. 

All manufacturing processes for medium voltage dry substations are completed on premises and all designs are completed in-house by our experienced staff of Engineers. This advantage, along with a large inventory of Electrical Steel and Wire assures customers of the industry’s shortest standard lead times.



Coils are Vacuum Pressure Impregnated (VPI) with solventless polyester resign, ensuring complete impregnation o fthe windings and insulation. The finished VPI coils are incredibly strong, readily dissipate heat and are protected against moisture, dirt, and most industrial contaminants. Winding designs vary based on voltage, BIL and application. For all units the insulation system will be 200 °C


The standard enclosure is NEMA 1, Category C construction. Enclosures are suitable for lifting, jacking, rolling or skidding with provisions for lifting from the transformer base. High voltage and low voltage ANSI ground pads are provided.

The enclosure paint finish is neat, clean and highly resistant to corrosion. Metal surfaces are thoroughly cleaned of scale, oil, grease, rust and other foreign matter before painting. Unless specified otherwise, paint color shall be ANSI 61 (light gray). NEMA 3R outdoor enclosures are available for applications that prohibit indoor installation.


The transformer cores are constructed of non-aging, high grade, grain oriented silicon steel laminations with high magnetic permeability. Magnetic flux densities are kept well below the saturation point. Core laminations are free of burrs and stacked without gaps. Mitered construction cores may be provided when specified. The core clamping brackets are designed to provide even distribution of clamping forces to the core yokes and legs. The core is electrically isolated except for the factory-installed core ground strap, which provides a single path from the core to ground.


All units rated 750 kVA and higher can have added fans, increasing capacity in all current carrying parts for the fan-cooled rating and capability to add a thermometer relay to control fans. When specified, the transformer shall be provided with fans to give a forced air-cooled rating of 33% above the self-cooled rating. Control wiring (wire markers included), a thermal sensor and a fan controller will be supplied.


The transformer shall be designed to meet or exceed ANSI and NEMA sound levels for dry-type transformers. As an option, transformers designed at -3dB below ANSI and NEMA standard sound levels are available.


When specified, transformers can be closecoupled to a multitude of High Voltage and Low Voltage Switchgear.


Each transformer shall receive the following standard production tests in accordance with ANSI C57.12.90

  • Resistance test
  • Polarity & phase relation test
  • Turns ration test
  • No-load loss & exiting current test
  • Impedance and load-loss test
  • Applied potential test
  • Induced potential test
  • Low loss designs
  • Rectifier transformer designs
  • Special ambient designs
  • High overload capacity designs
  • Special/low sound level designs
  • 50 Hz designs
  • Series/parallel windings
  • Retrofit to specific dimensions
  • K-factor ratings
  • Special Paint
  • Auto transformers
  • PCB replacement



Installations of ventilated dry-type transformers do not require a liquid confinement area, automatic fire extinguishing system or fire vault. Drytype transformers use no insulating liquids, virtually eliminating the risk of local environment contamination and simplifying routine maintenance by eliminating the need to check, replace or clean liquid. Dry-type units are relatively lightweight and can be conveniently installed on upper floors, balconies, roof trusses or roofs. Insurance companies generally offer lower premiums for installations of dry-types than for liquid-filled transformers.

Need it fast? We can deliver. Emergencies happen and we can expedite the manufacturing of your units to meet your delivery requirements. Ask about our Bull Rush program when you place your order and we can manufacture and ship your unit in as fast as 2 working days!

MGM Transformer Company can manufacture your units at our 120,000 square foot plant in the U.S. and source the raw materials solely from American companies if required. By doing so we can certify your units to be compliant with any of the various “Buy U.S.” statutes (either state or federal). Please make sure to specify your requirements at the time of order.

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