Here is a list of a few things to remember when purchasing a used or surplus transformer:

• First, make sure that the unit is one that suits your application.  If you're not sure, just ask!  A reputable dealer would be happy to answer any questions and steer you in the right direction.
• A transformer is an electrical device that is used to change voltage and amperage.  It does not generate power.
• In addition to pictures of the outside of the unit, ask to see photos of the coil and the core inside the transformer.  The core and the coil rust much faster than the sheet metal on the outside.  Some rust on the outside of the unit does not inhibit the functionality of the transformer and photos of the inside also lets you see if the unit is copper or aluminum.  We typically only post one or two photos of transformers to keep our listing fees down but we are happy to send as many pictures as necessary to a potential buyer so they feel comfortable that they are getting what they pay for.
• Lastly, consider the size of the transformer and the cost of shipping .  These items are very heavy and are almost always shipped by freight carrier.  Make sure that the seller knows how to properly pack and secure the transformer before shipping.