Abstract: An oil-filled, high temperature, submergible electric pump motor comprises an unvarnished stator structure having stator windings formed of conductors coated with hydrolytically stable, oil-resistant, and abrasion-resistant insulation exposed to the oil of the motor, and preferably selected from the group consisting PEEK, PEK, and PBI. The stator windings have end turns mounted on rigid, hydrolytically stable, oil-resistant electrically insulating blocks that support the weight of the stator windings and immobilize the end turns. The end turns are attached to the blocks by hydrolytically stable, oil-resistant electrically insulating tape. Other components of the insulation system are selected for their hydrolytic stability and oil resistance, and in some instances for their non-abrasive properties.