The drives are permanent magnet excited synchronous motors. KSB says their output per size clearly exceeds that of conventional asynchronous motors. With efficiencies being much higher, KSB adds that large savings and relatively short payback periods compared with asynchronous machines can be realised.

The motors are operated on a frequency inverter. The adjusted flow rates reduce the frequency of starts and, with that, the load on the winding. As this optimised operating mode also keeps the frequency of pump starts to a minimum, it decreases wear and extends the pump’s service life.

A mechanical seal prevents the fluid handled from mixing with the fluid in the motor space. The motor’s thrust bearing is water-lubricated and has self-adjusting tilting pads. Requiring no maintenance, KSB says it easily copes with the stresses and strains of continuous operation thanks to the material combination of stainless steel and hard carbon.

While the pump set is started up, the counter thrust bearing absorbs the axial thrust caused by the hydraulic system of the pump and prevents the impellers from coming into contact with the stage casings. This results in a high operating reliability and achieves the long service life customary for submersible borehole pumps.

UPA pumps with new energy-saving motors are characterised by a low power input and a long service life. (KSB Aktiengesellschaft)