Parker Hannifin - SSD Drives AC890PX Pump Drive
The Lift Station was constructed in the 1970’s to help accommodate a rapidly growing population, and includes three 200 HP centrifugal pumps, driven by standard AC induction motors. The facility can pump 11 million gallons per day, at a 143 foot lift. Pump flow was controlled by an eddy current clutch from the original installation. When the failure of one of the pumps’ drive systems occurred, the quoted repair cost was prohibitive. The decision was made to update rather than channel any more funds into last generation equipment.
Quick, Clean, and Easy Installation - The inefficient eddy current clutch was removed, and the existing 447T-frame motor directly coupled to the pump shaft, requiring only a simple motor mount modification. The 200 HP AC890PX was then powered up through the existing control panel and pump sequencing logic. The available bottom power entry configuration on the AC890PX made for a clean installation with no visible wiring. No expensive external harmonic filter was required, as the AC890PX includes a 3% line reactor, built into its enclosure, as well as line fuses and a local power disconnect switch with door interlock and lockable handle.
Energy Costs Reduced - Replacing the existing speed control device with a solid state drive provides several tangible benefits to the city of Rock Hill SC, including energy efficiency. Eddy current clutches rely on slip to adjust the speed of their load, and dissipate energy wastefully as heat. Their efficiency drops off significantly with speed. On the other hand, by using an adjustable speed drive like the AC890PX to regulate the speed of the pump directly, there is no energy lost to slippage, and the current draw of the motor declines dramatically with reduction of speed. With a centrifugal pump, reducing the speed to 80% will result in nearly a 50% decrease in power consumption. The annualized energy cost savings after installing a single drive is estimated at $18,000 per year.
Less Wear and Tear - The 200 HP motor is now gently ramped up to speed with current limited by the drive. The old system started the motor across the line, resulting in a floor-shaking jolt and a high peak demand of current. Not only was this rough on the motor, but also on the power bill, as utilities meter their customers’ peak demands and penalizes them with surcharges based on their occurrence.
Higher Reliability - A benefit of the AC890PX drive is its reliability and reduction of down time. In the unlikely event of a component failure, the converter module, phase modules, and capacitor module are quickly removable and lightweight. Replacement of a module does not require a factory service person, nor does it require the return of the drive to the factory for servicing. In a matter of minutes, a module can be replaced, and the drive brought back on line.
For more information on the AC890PX, please visit http://www.ac890px.com
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