Open-well and fluctuating-level pumps are designed for use in open wells and tanks. These devices, which are located at the bottom of these voids, work under water; their prime movers—water cooled and rewindable when necessary—are powered by motors (or engines). Winding wires in the stators are insulated with a synthetic resin and lubricated under pressure, reducing energy loss by minimizing wear on laminates made of silicon steel.