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3.7.3 Changes in Line Voltage (Watch Line)
Motor status alarms associated with the changes in the line conditions are indicated by the "Watch
Line" message on the AES Viewer an AES Configuration and Motor Status 2 having the value of 2.
They are usually temporary in nature and generally the user does not need to take any action.
However, it is recommended that when this status level occurs, the user should at least assess the
extent of the change in the line conditions, as significant changes in the line voltages and currents
may be dangerous to the motor. If the line status change is persistent, the user should assess the
root cause of this change. For instance, it may be due to a problem in the contactors or for inverter
driven motors the settings of the inverter may have been changed. In any case, if the root cause
cannot be remedied easily and quickly and the new voltage supply condition presents no danger to
the motor, the user has the option to send eMCM to the UPDATE mode. This will allow MCM to
learn the new voltage supply conditions, after which the status will eventually return to normal.
3.7.4 Load changes (Watch Load)
Motor status levels associated with changes in the loading conditions occur with the "Watch Load"
Message on the on the AES Viewer an AES Configuration, and Motor Status 2 taking a value of 3.
They are also temporary in nature but they should be treated more carefully than line changes, as
some faults developing in motor-based systems can cause changes in the loading conditions. For
instance, leakages from pump seals can cause pressure drops, which will be interpreted by eMCM
as changes in the loading conditions. Similarly, clogging in a pipe or membrane or an increase in the
friction of moving parts will be detected as changes in the apparent load.
It is, therefore, important to assess the root cause of the load change. In certain cases, (for instance,
closing or opening a valve or changing a pipe), the changes in the loading conditions are intentional
and should already be known by the user. In such cases, the user should send eMCM to the UPDATE
mode so that it will learn the new loading conditions. When no obvious cause can be found, it is
likely that a fault is indeed developing and the situation should be monitored more carefully.
3.7.5 Error Messages
Unlike alarms, errors refer to failures of the eMCM hardware and software rather than the
monitored motor. When eMCM discovers an error condition it makes several attempts to recover,
and only if these attempts are unsuccessful is an error message generated. All errors stop eMCM
from functioning and must be cleared before proceeding further. Errors are indicative of a serious
problem within eMCM and their source should always be investigated. An error indication is
displayed error message on the AES Viewer and AES Configuration. When reporting device
malfunctions, please be sure to include both the message and its associated number. Please refer
to the appendix for a full list of error messages.
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