Cleaning of Dry Type Transformers
If excessive accumulations of dirt are found on the transformer windings or insulators this material should be removed to permit free circulation of air and to guard against the possibility of insulation breakdown. Particular attention should be given to thoroughly cleaning each end of winding assemblies, as well as ventilating ducts.
The windings may be cleaned with a vacuum cleaner, blower, or compressed air. The use of a vacuum cleaner is preferred. The compressed air should be clean, dry and should be applied at a relatively low pressure, (not over 25 psi.). Lead supports, tap-changers, terminal boards, bushings, and other major insulating surfaces should be brushed or wiped with a dry cloth. The use of liquid cleaners is not recommended due to solvents or other corrosive materials which could harm insulating materials. It is recommended that the manufacturer be consulted before any liquid cleaners are used.