4" Single-phase oil-cooled O3.DRP Motor (220-230V / 50Hz)

PSC single-phase submersible O3.DRP motors are manufactured to ISO 9001 standards and are designed to operate coupled to hydraulic parts with the same coupling dimensions.  Parts in contact with water  are made of stainless steel; cooling and lubrication of ball bearings are guaranteed by a FDA approved dielectric fluid.  O3.DRP motor requires a start and run control box (CBO, which includes capacitor and manual reset amperometric protection - see Accessories section for more information).  Supply cable connector, removable for quick and easy maintenance is equipped with the DRP protection device. The DRP is an electronic device, integrated into the connection cable that guarantees optimal protection of the submersible pump against dry running and other possible installation faults or operation failures. In case of water shortage, the DRP stops the pump when the water is below its sensor. The DRP (observing a programmed time) restarts the motor when the water rises above its sensor.



O3.DRP motors ensure reliable working in 4” or larger diameter wells. The axial and radial oil-lubricated bearings allow for maintenance-free operation. The pressure compensation inside the motor is ensured by a special internal membrane. Compared with traditional solutions, no additional cables or other dry-running sensors are needed when using O3 motors with DRP protection device.



  • The rewindable coated stator is inlaid into a 304L stainless steel casing, the design of 24 slots ensures more flexibility and smooth operation, it is varnished and  immersed in dielectric fluid to guarantee optimal cooling capacity of temperature during operation
  • The AISI 420B integral shaft ensures optimal performance thanks to the special surface hardening . The squirrel cage rotor is made of aluminium for all motor powers
  • Oversized ball bearings are completely silent and of high axial load
  • Motors ready to use, prefilled with dielectric fluid
  • Sand protection and mechanical seal designed to guarantee optimal operation even with high quantity of sand in the pumped liquid
  • Safety motor bottom cover for extra protection   
  • All motors are 100% tested
  • DRP protection device integrated into the connection cable available for all powers

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  • kW: 0,37 - 2,2
  • Voltage range: 220-230V / 50Hz
  • Flange: 4" NEMA standard dimensions
  • Voltage tolerance 50Hz from nominal: +6% / -10% Un
  • Rotation: ccw, facing shaft end
  • Degree of protection: IP 68
  • Insulation: F
  • Rated ambient temperature: max 40° C
  • Cooling flow: min 8 cm/sec
  • Maximum starts/h: 150, equally distributed
  • Mounting: vertical/horizontal, shaft upwards
  • Maximum immersion depth: 150 m
  • Allowed range of water pH: 6,4 - 8,0
  • Thrust: 1.500 N, 2.500 N, 4.500 N (according to ranges)
  • Protection requirements: For O3 motors without the control box CBO an overload protection and a control unit for motor start and run must be installed according to EN 60947-4-1 trip time < 10 sec. at 5xIn

Automatic protections

Dry-running protection

Dry-running protection

The DRP completely protects the O3.DRP motor against lack of water in the well, without the aid of other equipment (probes, cables, sensors, control panels etc.). In case of dry running, the DRP automatically stops the pump. When the water level is restored in the well, the DRP restarts the motor after a programmed cycle time.

Protection against too frequent start&stops

Protection against too frequent start&stops

The DRP protects the O3.DRP motor against leaks in the piping system (also when the pressure tank is exhausted or its membrane is defective, or when there is a defective pressure switch) and too frequent starts and stops (for example if the tank is too small for the system). In such cases, to avoid potential damages, the DRP makes the pump enter the stand-by mode.

Low voltage protection

Low voltage protection

The DRP protects the O3.DRP motor against low voltage. Low voltage can occur, for example, if the section of the power cable is not adequate considering the motor power and the distance between the plug and the pump itself; or if a generator is faulty or undersized for the pump.

Voltage peaks protection

Voltage peaks protection

The DRP protects the O3.DRP motor against voltage peaks, which can be caused by electric abnormalities in the supply network or by other various electrical interferences. It reduces overvoltage, keeping the correct operating voltage range.

Model performance


Information on a proper installation

  • Before installation, it is necessary to verify technical requirements of the given hydraulic part (thrust, power) to select the correct motor.
  • During installation of a motor, it is necessary to verify if the power supply voltage is correct.
  • The correct motor operation is guaranteed when the power cable section is correctly selected, considering the motor power and the distance between the pump and the plug itself.
  • If you are using a generator with an internal combustion engine, it is necessary that the generator’s power measured in kW (in continuous delivery) is three times the rated power in kW of the submersible pump.
  • To guarantee automatic operation mode (the pump starts and stops when open and close the tap) it is necessary to connect a pressure switch and a pressure tank of the correct size, if the plant is not already provided with them.
  • We recommend to install a proper cooling jacket in installations bigger than 10 cm, to guarantee the correct motor cooling flow.
  • The maximum quantity of sand allowed in the pumped water is 120g/m³.
  • The DRP must NOT be used with a frequency inverter.
  • DRP doesn’t work with demineralized water (such as rain water).
  • DRP must not be used as a float.
  • The DRP must be immersed in the same water as the pump in order to ensure continuity between the DRP and the pump casing.
  • In order to reset the electronic protection, disconnect the pump power, wait 10 seconds, then plug it in again.


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