Case Study: True Submersible Motor Ends Repeated Grinder Motor Maintenance Problem

The Franklin Township Sewer Authority had a repeated problem with an immersible motor on one of their grinders that was subject to flooding.
The Authority runs a pump station collection system in Somerset, New Jersey that handles 6 mgd of domestic and industrial wastewater. Grinders play an important role, finely grinding up incoming debris. This allows the wastewater to pass easily through the pumps and pipelines to the treatment plant. But at one of the pump stations the sewage grinder was supplied with an immersible type of motor that was a cause of reoccurring problems.

“The grinder was a bad engineering decision for that particular location,” said Assistant Superintendent, Scott Nocero. “The motor on the grinder we chose was immersible only as were the replacement motors. During heavy rain storms, the station’s wet-well was often flooded and we had to replace the motor several times. I did some research and my thinking was that if you install a truly submersible motor, you will not have to deal with the problem over and over again.”

“I became acquainted with Franklin Miller after two of our other pump stations installed the TASKMASTER® TITAN® Duplex grinders that feature submersible motors,” said Nocero. “I spoke to the Franklin Miller salesman who told me I could retrofit our grinder, even though it wasn’t a Franklin Miller, with a submersible motor. And that’s what we did.”

“The motor was custom fit to our grinder with some parts that were made in- house,” Nocero continued. “Everyone was very helpful, expediting everything because they knew the urgency of having a working grinder. Since the installation there have been no issues and no problems.” “We’ve been very satisfied,” he concluded.
Franklin Miller’s submersible motors have unique design and construction features that make them suitable for fully submerged operation in up to 200 feet (61m) of water and sewage as well as continuous in air operation under full load operating conditions. This provides an optimal solution for trouble-free grinder operation in applications subject to flooding.

Unlike immersible motors, FMI true submersible explosion proof motors offer dependable, submerged operation in either continuous or intermittent use. These motors are designed to provide high mechanical integrity under adverse operating conditions for maximum life and minimum life cycle costs. Their design requires no internal or external liquid cooling system.

These (IP68) motors are suitable for grinders and comminutors as well as other applications, as defined by the National Electric Code as Class 1; Division 1, hazardous locations section 501-8 (a) requiring submersible explosion proof construction.