Design

Application

• Drinking water supply and water supply from boreholes and rainwater storage tanks
• Process water supply
• Municipal water supply
• Sprinkling and irrigation
• Pressure boosting
• Pumping water in industrial applications and for water control
• Utilisation of geothermal energy
• Utilisation in offshore areas

Equipment/function

• Multistage submersible pump with radial or semi-axial impellers
• Hydraulics and motor freely configurable, depending on power requirements
• Non-return valve can be integrated (depending on type)
• Three-phase motor for direct or star-delta start
• Hermetically sealed motors
• Rewindable motors

Type key

Technical data

• Mains connection: 3~400 V, 50 Hz
• Submerged operating mode: S1
• Max. fluid temperature (higher temperatures on request):
  • NU 5... / NU 6… / NU 7… / NU 811 = 30 °C
  • NU 801 / NU 9... / NU 12.. / NU 16… / U… = 20 °C
• Minimum flow rate at motor:
  • NU 5... / NU 7... = 0.16 m/s
  • NU 611 = 0.1 - 0.5 m/s
  • NU 811 = 0.5 m/s
  • NU 801 / NU 9... / NU 12… / NU 16… / U... = 0.1 m/s
• Max. sand content: 35 g/m³
• Max. number of starts: 10/h
• Max. immersion depth:
  • NU 5…, NU 7…= 350 m
  • NU 611, NU 811 = 100 m
  • Remaining motors = 300 m
• IP rating: IP68
• Control range for frequency converter:
  • NU 5... / NU 6… / NU 7… / NU 811 / U 21… = 30-50 Hz
  • NU 801 / NU 911 / NU 12… / NU 16… (2-pole) = 25-50 Hz
  • NU 801 / NU 911 / NU 12… / NU 16… (4-pole) = 30-50 Hz

Construction

Hydraulics

Multistage submersible-motor pump with radial – semi-axial hydraulics. Housing parts made of EN‐GJL or EN‐GJS with 2K coating or G-CuSn10, impellers made of G-CuSn10 or NiAl‐Bz.

Pressure port as threaded connection (up to K 12...) or as flange connection. A non-return valve can be installed instead of the pressure port on types K 12..., K 14…. For the remaining types, a non-return valve can be mounted directly on the pressure outlet.

Motor

Three-phase motor for direct and star-delta start. Sealed, hermetically cast motor with enamel-insulated winding, resin-impregnated (NU 5…, NU 7…) or rewindable motor with PVC‐insulated winding (NU 611, NU 8…, NU 9…, NU 12…, NU 16…, U…).

Standardised pump connection. Sealing of the motor shaft is achieved through the use of a mechanical seal (NU… series) made of solid silicon carbide material or through the use of rotary shaft seals (U… series). Self-lubricating motor bearings. Thrust bearing with rockers for absorption of high axial thrust. Negative axial thrust is absorbed by the counter-thrust bearing.

Motors in the NU 5…-, NU 7...-, NU 801, NU 9…, NU 12… and NU 16… series are filled with a water‐glycol mixture, motors in the NU 611 and NU 811 series are filled with a water-glycerine mixture. NU 611-, NU 8…-, NU 9…-, NU 12… and NU 16… series motors can also be filled with drinking water (T version). U… series motors generally have to be filled with drinking water. Frequency converter operation is permitted (SF 1.1).

Cooling

The motor is cooled by the pumped fluid. The motor must always be immersed when operated. The limit values for maximum fluid temperature and minimum flow velocity must be adhered to. Vertical installation is possible with or without cooling jacket. For horizontal installation, bearing brackets must be used for reinforcement of the unit. An anti-vortex plate or cooling jacket may be used to improve the inlet flow.

Pressure shroud

The pressure shroud is used for the direct installation of the unit in the pipe system. Standard models are without mounted non-return valves. The maximum inlet pressure is 10 bar or 5 bar, starting from a pressure shroud diameter of 559 mm.

Scope of delivery

• Hydraulics + motor completely assembled
• Connection cable approved for drinking water, cable cross-section and length per standard design or per customer request
• Installation and operating instructions

Options

• Special materials
• Drinking water version with ACS approval
• 60 Hz version
• PT100 sensor for thermal motor monitoring

Accessories

• Cooling shrouds
• Pressure shroud
• Bearing brackets and anti-vortex plate
• Non-return valve
• Transitions
• Switchgears
• Plastic cable connector set