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PROCESS Worldwide-03-2009
Enabling planned maintenance
KSB is showing off a monitor developed for canned-motor pumps by joint venture partner Nikkiso. To date, Nikkiso has supplied more than 30,000 of these E-Monitor units around the world.
The E-Monitor monitors the status of the axial and radial bearings and flags up any changes in their condition. Provided a canned-motor pump is operated properly, its plain bearings should give reliable service for up to 8–10 years, KSB says—but if a bearing does fail, the result can be costly damage to the can and windings, as well as unplanned downtime. By predicting when it is time to change the bearings, the E-Monitor helps operators schedule their maintenance and avoid failures. The monitor uses eight sensors mounted in the stator space to check the magnetic field of the rotor. Bearing problems cause the rotor to move out of alignment, generating an unbalanced magnetic field that is detected by the monitor. Green, amber and red “traffic lights” show the bearing status, and the monitor can also interface to a distributed control system via 0–5 V and 4–20 mA analog outputs. The E-Monitor takes its power from the motor’s terminal box, so it does not need a separate power cable.
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