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3. Diagnostic Function
3.1 Introduction
Having configured eMCM for a particular motor, it can now be used for its intended purpose of
monitoring and assessing the condition of the motor. In general, this involves first running eMCM
to measure and learn the properties of the motor and then running eMCM in its test mode to
perform the actual monitoring.
Without the learning period eMCM has insufficient
information on which to base its decisions as the motor
ages and will not perform to its specifications.
For this reason, e MCM ensures that a valid learning period is first performed before allowing the
user to request the device to monitor the motor.
3.2 Alarm messages and status indication
3.2.1 Alarms specific to the motor
eMCM divides warning messages into the categories of warnings, alarms and errors. Warnings
inform the user that non-critical conditions have arisen that the user should be aware of but do not
affect the performance of eMCM. Alarms provide information specific to the motor being tested
and are indications of faults caused by incorrect connections to the motor, the supplied line voltage
and/or motor currents being outside the specified limits and other conditions that prevent eMCM
from correctly determining the state of the motor. Alarms do not cause eMCM to stop monitoring
completely, but generally are indications that there is something that needs to be investigated and
possibly changed before eMCM can function to its full extent. In some cases, an alarm may indicate
a transient event such as high line voltages, which although damaging to the motor in the long term,
do not indicate an immediate need for action. Of course, if the frequency of such events is
sufficiently high, the cause should be located and corrective action taken to remedy the problem.
It is important to realize that when an alarm is displayed,
eMCM does not process the data taken from current and
voltage channels. Therefore, eMCM cannot monitor the
motor status.
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