Hydraulics

Multi-stage submersible pump with semi-axial hydraulics. Housing parts and impellers made of stainless steel investment casting (1.4408). Discharge port with threaded or flange connection available with or without integrated non-return valve. Motor connection as standard NEMA connection (up to 8″) or standard Wilo connection (from 10″).

Motor

Asynchronous and synchronous motors can be selected as the drive:

• Asynchronous three-phase AC motors for direct and star-delta starting:
  • NU 501, NU 701: Hermetically sealed motor with enamel-insulated winding, resin-impregnated
  • NU 611, NU 811, NU 911, NU 122, NU 160: Rewindable motor with insulated PE2 or PVC winding
  • Operation on the frequency converter is permitted!
• Synchronous three-phase permanent magnet motor for direct starting:
  • NU 512: Hermetically sealed motor with enamel-insulated winding, resin-impregnated
  • NU 612, NU 711, NU 812: Rewindable motor with insulated PE2 winding
  • A frequency converter is absolutely necessary!

Motor shroud made of steel, stainless steel or bronze casting. Hydraulic connection as standard NEMA connection (up to 8″) or standard Wilo connection (from 10″). The motor shaft is sealed with a mechanical seal made of solid silicon carbide material. The motor bearings are self-lubricating. The thrust bearing is equipped with rockers to absorb the high axial thrust. The counter-thrust bearing absorbs the negative axial thrust.

Motors in the NU 5 … and NU 7 … series are filled with a water-glycol mixture. All other motors are filled with a water-glycerine mixture.

Cooling

• The motor is cooled by the pumped fluid. The motor must always be immersed.
• The limit values for maximum fluid temperature and minimum flow velocity must be adhered to.
• Vertical installation is possible with or without cooling shroud.
• In horizontal installation, the unit is supported by bearing blocks. An anti-vortex plate or cooling shroud may be used to improve the inlet flow.

Options