Reliable Power Must Be Maintained In Critical Systems
September 10, 2013
It might not be economical for most facilities to collect detailed data about motors and drives to populate a CMMS, so the next best approach is to create a plan managers can use consistently when making repair-or-replace decisions. The plan should address such questions as:
How large is the motor or VFD?
What does the motor or VFD serve?
About how old is the motor or drive?
What is the component's expected service life?
What is known about the maintenance history?
For small motors, it is generally most economical to simply replace the motor. For large motors used in some institutional facilities or campuses, the most cost-effective decision can be to repair or rebuild both small and large motors. The key is to estimate when the cost of repair and current levels of maintenance exceed the cost of replacement.
If a manager does not know the installation date of the motor or drive, the next step is to estimate the date by determining the installation date of the parent asset and comparing the visual appearance and any wear on the motor or drive to the parent asset. For example, if a chilled-water pump was installed when the building was constructed and the motor looks to be the same age as the pump, it might be safe to assume the motor and the pump are the same age. Asking the maintenance technicians who have been at the facility for the longest time about the history also can be especially valuable.
Whether or not to repair VFDs will depend on their condition. VFDs are electronic, so they have fewer moving parts that can fail. But if the drive has truly failed — if its control panel no longer functions, for example — the general practice is to replace it.
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