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(R) slotted brushless d.c. motor components from Pittman (Harleysville, PA, U.S.) deliver the power. Operation is further optimized due to Pittman's On-Motor(TM) control electronics 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 Water Systems. "It worked."
From the outset, motor construction and ease of configuration with the SmartPump design were at the top among decision-making criteria that would influence the project's success. As a result, pump and motor components become integrated as one unit. Pittman provides complete "unhoused" ELCOM ST slotless brushless d.c. motor assemblies (including stator, rotor featuring bonded neodymium iron boron magnets, and On-Motor electronics), which are then incorporated into SmartPump by Wayne.
The motor's 8-pole rotor is integrated with the SmartPump's impeller. The impeller/motor rotor rotates on the motor's 2.5-in long stainless-steel (corrosion-resistant) shaft. The durability of the rotor's magnets is especially appreciated, reports Mr. Mayleben, since the rotor often is exposed to water.
"In terms of the impeller, the ring-type magnet arrangement further serves a dual purpose," adds Mr. Mayleben. "It works to turn the impeller and acts as a leakage-control device." In the SmartPump, the magnet is utilized 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 Pittman.
By taking advantage of Pittman's integrated On-Motor control electronics, potentially complicated hookups were eliminated, according to Mr. Mayleben. The PC board serving as a platform in the SmartPump application is circular and mounted concentrically onto the motor's stator.
"The customer [Wayne] supplied the basic outline of the pump and the stator location," says Jon Haas, R&D engineer for Pittman. "Our job was to integrate the drive electronics and the interconnection into something that could be potted or molded. It required us to design the PC board in such a way that it would be a mating member to the electronics and the mechanical part of the stator." The final challenge was being able to fit all the electronic components on the PC board. "By custom designing our On-Motor electronics, we were able to fit the necessary components on the PC board," says Mr. Haas.
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," Mr. 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 "self-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 24-V motor assembly offers an added capability to operate independently of the pump's system controller. This enables service as a stand-alone 24-V d.c.-powered sump pump maintaining basic ability to turn on and shut off using dual magnetic reed float switches built into the SmartPump system.
According to Pittman, its ELCOM ST slotted brushless d.c. 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 d.c. motor products.
The stator features 6-slot steel laminations (thousandths of 1-in 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 8,000 rpm and continuous torque output up to 49 oz-in can be achieved.
"No matter how demanding the conditions," Mr. Mayleben observes, "we've been able to realize with this system the highest levels of functionality and performance consistent with our standards."
Special Product Supplement
Motors & Air-Moving
by Peter Simmons, Assistant Editor
- The Art of Providing Savings
- Electric Motor Testing on the Production Line
3 - Integrating Brushless D.C. Motors
Into Plastic Fans for Efficient, Quiet, and
Cost-Effective Appliance Solutions
4 - Design Platforms
5 - Discovering the Use of Tangential Blowers in Low-Noise Applications
Automated and Data-Reliant
7 - Improving IAQ
in the Home
8 - Floor Care
Appliance Boasts 5,000-HR Life
9 - Getting