Three phase transformers are used on three phase energy systems either as security - isolation type transformer or  step up -down transformer, in some cases step-up and step down transformers can be produces as auto transformer for reducing the price.     
         •   Nominal Power
         •   Isolation type or auto type
         •   Input-output voltage and current values according to duty factor
         •   Input - output connection types ( delta - star etc )
         •   Galvanic isolation
         •   Input - Output voltage steps
         •   Input-output connection materials
         •   Isolation class
         •   Metal enclosure and ventilation
         •   Mounting type ( horizontal - vertical ) ... etc
GUVEN-IS determines these technical specifications by communicating directly to the customer before designing process in order to avoid any problem.  When every detail is clear a sample transformer is produced and tested by GUVEN-IS and submitted to the customer for the final approving before the ordering.