As a public water provider, Loudon Water, a water and wastewater authority in Loudon, Va., must be able to supply water to meet the community's needs. As a non-profit organization, it needs to prevent lost revenue that can result when a pump fails or is subject to unplanned downtime. To maximize uptime and customer satisfaction, Loudon Water teamed with a manufacturer of accelerometers and vibration monitoring products to install vibration sensors on four pumps to maximize uptime at a new pumping station.

Loudon Water chose to implement simplified continuous pump monitoring that interfaced with its existing SCADA system. Four separate motor/pump combinations at a single remote pumping station were chosen for monitoring. Three pumps were impeller between bearing pumps. The remaining unit was an overhung impeller pump. For maximum protection, permanently installed accelerometers were mounted on the inboard and outboard bearings of the motor and pump. Because of its broad application potential, general purpose (100 mV/g) industrial accelerometers were chosen. The signal was then fed to DIN rail mountable intelligent transmitters. These vibration transmitters were housed in an enclosure local to the machine. This provided a termination point for the vibration signal conditioners, power supply and cables as well as a means of determining present condition at the machine.

Each of the 16 general purpose sensors captures a unique signal from its bearing location. The sensor signal is forwarded to a dedicated intelligent transmitter where the time domain signal from the accelerometer is processed into a 4-20 mA signal. This 4-20 mA signal, which represents the overall vibration velocity, is then tied into the water authority's existing SCADA system. The result is 24/7 online vibration monitoring at the pumping station with both local and remote monitoring capabilities. Loudon Water chose an intelligent transmitter because it includes a 4-20 mA output signal for simple trending and a front-panel BNC connector to access the dynamic data when additional vibration analysis is needed.

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Loudon Water had already experienced a catastrophic failure because it had no monitoring equipment on its pumps. If a vibration monitoring program had been in place to detect a failure, the water authority may have saved thousands on pump repair and parts replacement as well as downtime and lost revenue. It implemented vibration monitoring for condition based maintenance as an investment in reliability to help detect and prevent problems and better serve customers.

As a result of implementing this system, Loudon Water has maximized uptime and minimized unscheduled maintenance. Its belief in this system is evidenced by including continuous vibration monitoring requirements into planned station upgrades.

Dynamic Accelerometer and Velocity Sensor Options

  • Sensitivities from 10 mV/g to 500 mV/g and from 20 mV/ips to 500 mV/ips
  • 3 dB frequency response from 0.1 Hz to 25 kHz
  • Top or side exit
  • Maximum temperatures from 120 deg C to 150 deg C

Intelligent Transmitter Options

  • Monitor acceleration, velocity or displacement
  • Measure root-mean-square, peak, true peak or peak-to-peak
  • 3 dB frequency response from 0.3 Hz to 20 kHz
  • Selectable full scale range
  • Buffered dynamic output for portable data collectors and analyzers
  • 4-20 mA signal transmission
  • Eight-pole low pass filter and two-pole high pass filter

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Pumps & Systems, May 2010