Next-generation submersible motors to be launched

South Africa-based pumping system solutions provider Franklin Electric South Africa (SA) is working on launching its next generation of 4" submersible motors, following the success of its previous motor, which achieved a life span of 30 years.

Franklin Electric SA product manager Jano Verreynne comments: “The company is one of the oldest submersible motor manufacturers in the world and the Franklin Electric 4" motor has been the worldwide driving force behind residential and light commercial submersible pumps for decades.”

He points out that one of the company’s customers, Chris Prinsloo, a qualified electrician, “did a double take” when he removed the Franklin Electric 4" submersible motor from his borehole after 30 years of use, discovering that it was still in perfect working condition.

Verreynne explains that client testimonials such as these are not unusual for Franklin Electric SA’s product line of submersible waterlubricated motors, with at least two other motors he is aware of still operating faultlessly since they were first bought in 1978 and 1972.

“We’ve exchanged our client’s 30-year-old motor with a new motor, so we could put the old one on display to showcase its long-standing performance,” Verreynne highlights.

Franklin Electric SA application engineering manager Lyon van der Merwe notes that about 1.2-million of the company’s 4" submersible motors have been sold in the country since it was established in South Africa in 1972.

Since then, Verreynne points out, Franklin Electric SA has grown to be the largest supplier of installed submersible borehole pump motors, water pumping systems and submersible petrol pumps in Southern Africa.

New Offering
Verreynne notes that, although no official date has been selected, the company will be launching its next generation of 4" submersible motors, with upgrades that include an all 316 stainless steel design, including the casing and the top and bottom end bells.

He adds that the new design incorporates a novel lead-out plug sleeve for ease of installation and to reduce the risk of water ingress. The new model also has an outer fill solution replenishing option using a syringe.

Verreynne adds that the motor’s design also includes a cable clamp solution that uses only one T25 hexalobular slot combination head screw that can be torqued down to a positive stop with a well-defined torque of 3 Nm to 4.5 Nm.

He explains that, in accordance with the original design, the motors remain water- lubricated as opposed to oil-filled, which reduces the risk of borehole water contamination or the motor malfunctioning should external water leak into its components.

He comments that, in addition, the depth of installation of the motor has no adverse effect on its performance, as the pressure on the exterior of the motor and interior pressure of the water-filled motor are equal.

“Oil-filled motors are cheaper to manufacture, but, in the long term, water-filled motors are much more cost effective with an extensively longer operational life span, as the Franklin Electric motors have demonstrated,” asserts Verreynne.

With the new design, Franklin Electric SA has been able to reduce the amount of dissimilar materials used in motor construction and it expects this to improve not only the look and feel but also the motor’s performance when it is used in slightly aggressive environments.