Motor-pump unit for horizontal pond installation with cooling jacket and temperature sensor

Our customer, Pumpentechnik und Elektro Pauli GmbH, recently delivered a high-performance motor/pump unit to an agricultural operation. The system, consisting of a submersible motor with PT100 temperature sensor, a submersible pump and a cooling shroud, is a key component of a modern field irrigation system. It is used to supply a Rollomat irrigation machine, ensuring efficient and reliable watering.

Installed Components:

• 10" submersible pump VSI 254/03
• 8" rewindable submersible motor, 67 kW, ΥΔ with 6 m connection cable
• PT100 temperature sensor
• Stainless steel cooling shroud
• Suction strainer

The high-performance VSI series pumps achieve efficiencies of up to 85% and are known for their excellent corrosion resistance. Both the casings and impellers are made of highquality precision-cast stainless steel. Depending on the configuration, they can deliver flow rates up to 650 m³/h and heads of up to 600 meters.
The 10-inch version used in this application delivers up to 350 m³/h, depending on the total head.

Franklin Electric’s rewindable motors are available with power ratings up to 400 kW. The 8-inch rewindable submersible motor used in the system from Pumpentechnik und Elektro Pauli delivers a power output of up to 67 kW. These motors feature premium-grade, rewindable windings that can be replaced if needed. Thanks to hydrodynamic, liquid-lubricated radial bearings and heavy-duty Kingsbury type thrust bearings, the motors are completely maintenancefree. The electrical design ensures high efficiency and low operating costs.
The SandFighter™ sealing system with SiC/SiC mechanical seal provides optimal protection against abrasive media such as sand.

Horizontal Pond Installation with Cooling Shroud

Instead of being installed in a conventional well, the motor/ pump unit was mounted horizontally in a pond with a
depth of approximately 4 meters. To ensure adequate motor cooling, a cooling shroud was used. This separate
metal sleeve is sealed above the pump intake. The pumped medium is thus drawn in from below and directed along the motor, allowing the generated motor heat losses to be dissipated via convection.

The heat loss produced by the submersible motor is transferred to the pumped medium through convection. If the minimum cooling velocity along the motor is not maintained, the installation of a cooling shroud becomes essential to ensure proper heat dissipation. This is particularly important in open water bodies such as lakes, reservoirs, rivers, or tanks. A cooling shroud is also often required when the well diameter is too large, inflow occurs from above, or the flow rate is insufficient.

Components of the cooling sleeve kit
1 Cooling sleeve tube (Stainless steel)
2 Pump sealing ring (EPDM) with drinking water approval
3 Motor spacer
4 Pipe clamps
5 Filter strainer (accessories)
6 Console (accessory for horizontal mounting)

PT100 temperature sensor
The customer opted to install an additional PT100 temperature sensor. This is a high-precision platinum sensor with a linear resistance-to-temperature characteristic. The sensor is installed in the upper endbell, measures the temperature above the winding head, and thus continuously monitors the winding temperature.
The PT100 temperature sensor is equipped with a 4-core shielded cable, available in various lengths, providing additional protection against high-frequency interference that can occur in applications with frequency converters.