Motor Information


Reliable Insulation Wire

The coil conductor itself is coated with insulating materials of outstanding waterproof properties. Polypropylene insulation is generally used for water tight insulated magnet wire for submersible motors, A nylon sheath is used for mechanical protection over the Polypropylene insulation layer. We use specially developed denatured Polypropylene which offers very stable waterproof characteristics. The unique insulation structure shown below is as a result of extensive development and has proven to be of a far superior quality. Thus resulting in long insulation life under severe operating conditions.

770 F (260 C) Water Temperature

The motors operate with a flow rate O.5 ft/sec. (0.15 m/sec) in water temperature up to 770 F (260C) without any derating of horsepower. This 770 F (260 C) temperature is within NEMA standards. For applications where water temperature is elevated, consult Pumps Unlimited for correct application of motors. Motors can be provided for higher temperature applications.

High Torque Characteristics

The high quality electrical grade silicone steel laminations and proper design for allowance of voltage variation make up the high torque qualities of the submersible motor.


The rotor balance ring (one on each end of the rotor) allows for excellent dynamic balance for the rotating element of the motor.

Carbon Sleeve Bearings

Two carbon, water lubricated, bearings are used as guide bearings. These have an extremely large surface area and results in extra alignment supportless whipping and acts as a steady bushing.

Complete Corrosion and Water Tight Protection

All main motor components are made of stainless steel: including the can housing, shaft and bolts.

Quality Control

All submersible motors are manufactured and tested under the most stringent quality control procedures. This assures that you receive a motor that will give long service life and trouble free operation.


The well established KINGSBURY design thrust bearing creates a wedge of water between the pivot shoe and carbon disc. Our innovative design permits high thrust loads to be placed on the bearings while showing no measurable wear after several years of severe duty operation. This allows for long pumping life, virtual trouble free operation and low maintenance. For all 8″ and 10″ motors, the 1,000 lbs. maximum continuous up-thrust is carried between the upper slide plate and the separate upthrust carbon bearing.

The reliability of submersible motors depends upon their insulation characteristics. We have carried out continuous research and development of submersible motors for many years, drawing upon its total corporate technology.
These efforts have resulted in new patented water tight insulated magnet wire having excellent insulation characteristics. This patented technology is being applied to all water tight submersible motors. For the insulation material, specially developed denatured polypropylene is applied over a special enamel layer. An external nylon sheath is applied over this polypropylene layer for extra mechanical protection. These three insulation barriers are applied to copper conductors for complete insulation from the cooling fluid. This guarantees that submersible motors will have an extremely long service life.