Wiring Diagram

Dimensional Drawing

All specification subject to change without notice. Please contact MIDWEST for certified drawings.

Purchasing used, reconditioned, and new transformers

Used vs. new low voltage general purpose transformers

MIDWEST has tested, maintained, and reconditioned electrical switchgear, including low voltage general purpose transformers, for over 30 years.  When asked if one should purchase a used or reconditioned transformer, instead of a new transformer, MIDWEST recommends purchasing the new transformer.  The availability of used transformers in the secondary market does not suggest a used or reconditioned or new surplus transformer is better than a transformer new from the manufacturer.  Transformers have a reliable life expectancy, say 40 years, and there is an expectation that new transformers are designed better, are built with better dielectric materials, and are more energy efficient.  We know that select older used transformers may be more reliable in some cases because many of the older used transformers were overbuilt.  They might endure the overloading and abusive environments of some installations possibly better than a new transformer.  But this single statement does not permit a blanket statement suggesting used and reconditioned transformers are better than new transformers.  There is one additional caution relative to new transformers.  In a market driven by financial decision makers and in facilities not having staff engineers, MIDWEST often sees a facility purchase transformers totally unacceptable to their application.  A transformer may appear to be a dumb metal box to an outsider, but it is important to specify a transformer appropriate in design and quality for your application.  There is a difference in the design of a transformer for a mission critical facility or hospital or data processing center and the design of a transformer for a shopping center.  All used and new transformers are not alike in reliability and design application.  MIDWEST has electrical power engineers who have the experience and technical expertise to determine the proper transformer for your needs.

Who purchases used, reconditioned, and new surplus transformers

The marketplace for used, reconditioned, rewound, remanufactured, new surplus transformers exists because of several critical challenges to the market for new equipment.  The most critical challenge is the availability.  Many transformers are not available from stock and may take weeks to deliver.  Large transformers may take months.  Transformers come in so many different sizes and voltages that there may be no immediate stock of some voltage size combinations.  And if a manufacturing facility operates using a "just in time supply chain," they require immediate availability.  The only apparent choice may be a used or reconditioned transformer.  Another choice may be to rent a used transformer until you are able to specify and obtain the proper new transformer.

How do you know the transformer is reliable

When purchasing a used or reconditioned transformer, it is extremely important to purchase it from a company that completely tests the transformer.  There are standard specifications for testing transformers.  But MIDWEST goes far beyond the industry standard.  Because of our long history of servicing and selling new and used switchgear, MIDWEST has additional special load, voltage and function tests that assure the reliability of used and reconditioned transformers.  MIDWEST’s Quality Control Program (QCP) is your quality assurance.  MIDWEST must express caution because many used equipment suppliers, internet auction sites, and resellers do no more than clean and paint the transformer.  Some service companies might also perform turns ratio and insulation resistance tests on the windings.  These tests are not assurance of reliable operation.  MIDWEST recommends purchasing only from an experienced service company that has an exceptional Quality Control Program.