ducts through the s tator core and by reduc ing heat transfer f rom the winding in sulation surfaces
to the cooling air. Condu cting contaminant s ca n c han ge or increase electr ic a l stresses on the
insulation and c orrosive cont aminants can che mically attac k and degrade the insulation. This
may lead to shortened insu lation life and failu re.
Several satisfac tory methods of cleaning stator windings and stator cores ar e offered below :
Compressed Air
Low pressure (30 psi max.), clean (no oil) and dry air ca n be used to dislo dge loose dust and
particles in inacce ssible areas such as air vent ducts in the st ator core and vent pass ages in the
winding end-turns. Excessive air pressure can damage insulation and can drive contaminants
into inaccessible cracks and crevices.
Vacuum
Vacuum cleaning can be use d, both before and aft er ot her methods of cleaning , to remove
loose dirt and debris. I t is a v er y ef fective way to remov e loo se surface contamina tion from the
winding without scatt ering it. Vacuum cleanin g tools should be nonm etallic to avoid any damag e
to the winding insulation.
Wiping
Surface contamination on the winding can be removed by wiping, using a soft, lint-free
wiping material. If the c on tamination is oily, the wiping material can be moistened (not drippi ng
wet) with a safety-ty pe pe troleum solvent, suc h as S t oddard solvent. In ha z ar do us locations, a