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Smart sump system: pump system boosted by motor & control electronics.

As a large manufacturer of sump and utility pumps, Wayne Water Systems, Harrison, OH, has had its share of product innovations. The latest is their SmartPump, which can serve as both a primary and a backup system. This "intelligent" pump features a microprocessor-based system controller able to run a self-diagnostics test daily, detect pump jams, clear itself of debris, and alert homeowners to pump problems via a remote display.

Inside the SmartPump's cast-iron motor housing (potted in urethane), customized ELCOM ST slotted brushless DC motor components from Pittman, Harleysville, PA, supply the spin. Operation is further enhanced with Pittman's On-Motor control electronics, which are mounted onto a PC board within the motor assembly.

"The goal was to marry the performance of SmartPump and Pittman motor," notes Phil Mayleben, senior project manager for Wayne. "It worked."

From the outset, motor construction and ease of configuration with the SmartPump design rose to the top among decision-making criteria that would influence the project's success. Design engineers from both Wayne and Pittman partnered early and often throughout system development. As a result, pump and motor components became integrated as one unit. Pittman provided complete "unhoused" ELCOM ST slotless brushless DC motor assemblies (including stator, rotor featuring bonded neodymium iron boron magnets, and On-Motor electronics), which were then incorporated into SmartPump by Wayne.

The motor's 8-pole rotor is integrated with the SmartPump's impeller. The impeller/motor rotor rotates about the motor's 2.5-in. long stainless steel stationary shaft. The durability of the rotor's magnets is especially appreciated, reports Mayleben, since the rotor gets exposed to water.

"In terms of the impeller, the ring-type magnet arrangement further serves a dual purpose," adds Mayleben. "It works to turn the impeller and acts as a leakage-control device." in the SmartPump, the magnet is used as a replacement for the "wear ring" required in centrifugal pumps, and is located in the front, instead of the back, of the pump.

If required, SmartPump's system can convert from electrical to battery power, so it can operate without interruption even when electricity is unavailable. Pittman's brushless motor assembly is credited for contributing to system efficiency, helping to pump "the most gallons on a single battery charge," according to the company.

By taking advantage of Pittman's integrated On-Motor control electronics, according to Mayleben, potentially complicated hookups were eliminated. The PC board serving as a platform in the SmartPump application is circular and mounted concentrically on the motor's stator. The motor's controller communicates digitally with the SmartPump's system controller across ground and negative power wires. More than 20 different troubleshooting, warning, and test-related codes are programmed for dialogue between motor and system controllers.

"As examples," Mayleben explains, "should the rotor become locked or if the pump were to jam, the motor's controller would relay these conditions to the pump's system controller. Alerts then would be posted immediately on the SmartPump display unit for action."

The communication link runs from system controller to motor, as well. For instance, were the "sell-test" or "test" mode keys to be pressed on the keypad of the remote display unit, the pump's controller would send the proper command to the motor to perform and verify.

SmartPump's motor assembly allows it to operate independently of the pump's system controller. This setup enables service as a stand-alone 24 VDC sump pump, maintaining basic ability to turn on and shut off using dual magnetic reed float switches built into the system.

Pittman's ELCOM ST (Series N2300) slotted brushless DC motor achieves commutation electronically by utilizing a permanent-magnet rotor, wound stator, and rotor-position Hall feedback sensing scheme, instead of a mechanical commutator and brushes found in brush-type DC motor products. The stator features 6-slot steel laminations, each thousandths of an inch thick, which are fused to form a solid uniform stack and create a series of teeth. Wound copper coils, which produce electromagnetic fields, are inserted into each of the slots. Together, the laminated stack and wound copper coil form the stator assembly. The return path completing the magnetic circuit consists of the laminated material surrounding the copper windings in the stator and the motor housing.

With brush wear and arcing factored out of the performance equation, the motor can provide rapid acceleration and high speed, generate less audible noise and less electromagnetic interference, and promote long life with low maintenance. Speeds up to 8000 rpm can be achieved with continuous torque output up to 49 oz-in. (up to 75 oz-in. with heat sink).

"No matter how demanding the conditions," Mayleben observes. "we've been able to realize with this system the highest levels of functionality and performance consistent with our standards."--SG

Circle 224--Wayne Water Systems, Harrison, OH. www.rsleads.com/ 312df-224

Circle 225--Pittman, Harleysville, PA. www.rsleads.com/312df-225

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Title Annotation:Revision X
Publication:Designfax
Date:Dec 1, 2003
Words:789
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