Water Well Journal

March 2016

Water Well Journal

Issue link: https://read.dmtmag.com/i/643500

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Page 29 of 85

S o do you know what kills submersible motors the fastest? Heat. "It's the number one reason for water system failure," says Rick Campbell, manager of inside technical support at Franklin Electric in Fort Wayne, Indiana. Heat is caused by one of two things: electrical conditions or mechanical conditions. By protecting a pump against both, you'll ensure a system's longevity and create happy and loyal customers. Here are six ways heat could be killing your customers' submersible pump motors too soon. Make sure you know how to combat each of these to make sure customers get the most out of their water systems. No. 1. Improper voltage or voltage surges The motor has to have good voltage in order to operate. Improper voltage or voltage surges are the most common cause of electrical heat. The first thing to do is make certain the voltage coming in matches the motor you're using. "I like to use a lot of automotive industry analogies," Campbell explains. "You have gasoline and diesel fuels. You don't want to put gas in a diesel engine and vice versa." There are two operating systems in the residential market- place: 115 volts and 230 volts. When you get into the indus- trial marketplace, the voltage matters even more because you need to be sure it not only matches, but is also balanced. Three-phase power is created by three individual lines—all being single-phase by themselves—married together in order to operate the motor. Each phase must be balanced. "To use another automotive analogy, it operates like a three-cylinder car engine," Campbell says. "If the cylinders are not firing in proper sequence, the car runs rough. With a submersible motor or any electric motor, if it runs rough it gives off heat. Heat is the ultimate killer." A power surge, which is often caused by lightning, can damage the windings in the motor and seize them up, says Eric Neubecker, MGWC, vice president of Raymer Well Co. in Marne, Michigan. "Typically, we see that after a thunderstorm even though people don't have any other damage," he notices. "Because the submersible motor is right in the groundwater, it's the perfect ground. The current is seeking ground, so it inevitably goes to the motor." Storms can cause one leg of a three-phase motor to go out, which causes single-phasing. "If a storm outage occurs, we may not lose all three phases; we may only lose one of the three," Campbell ob- serves. "When that happens, the motor will try to run on any voltage it gets even though it will not run correctly. It will at- tempt to run until it sacrifices itself or somebody turns off the power." Because the current draw inside the motor increases, it cre- ates heat in the motor windings and eventually kills the motor. To prevent voltage surges from taking out a motor, you can use temperature compensating quick trip overload protection. "Trip class 10 is not always fast enough to respond appro- priately, so they need quick trip protection," Campbell says. "They also need temperature compensating because the motor is at a relatively consistent temperature, but the overload itself could be in extreme conditions from January in Alaska to July in Phoenix. You don't want heat or cold to change the re- sponse of the overload device." Lightning arrestors, surge protection, and good ground rods give voltage somewhere to go—rather than through the well. "We install our VFD pumps with an externally wired lightning arrestor just for safety reasons," says Steve Smith, president of Smith Pump Co. in Hooksett, New Hampshire. Here's why your customers' pump motors are dying too soon. By Jennifer Strawn SUBMERSIBLES continues on page 28 Twitter @WaterWellJournl WWJ March 2016 27 "The larger the tank, the less the pump starts and stops . Starting and stopping is bad for every component of the system." Photo courtesy Miller Well Drilling in Hayesville, North Carolina. Six Reasons Submersibles Submersibles Fail Fail

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