Chapter 6—Motor Protection
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
www.eaton.com
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Using the C445UM user interface or the Power Xpert
in
Control Software Tool, navigate to the following parameter.
Password settings are in the PRG
R
Security menu in
C445UM.
USB Password – to set the password (default 0). Register
5004
USB Password – to login (enter password). Register 5006
Note:
The USB Password parameter USB Password will
display a value of 0 if a no password has been
programmed into the unit (default). If the C445 has
been programmed with a password, a value of 0 will
be displayed if logged out, or a value of 4,294,976,295
will be displayed when logged in, in order to obscure
the set password value.
Fault Trip, Fault No Trip and Fault Warning
A Fault Trip event occurs when any enabled protective
parameter causes motor stoppage. A Fault Trip must be
corrected or cleared, before the C445 can enable return to
running operation.
A Fault No Trip event may be configurable for all protections
or combination of protections. When “Fault No Trip” is
configured for a protection, the C445 shall perform the same
protection logic as a “Fault trip” except the C445 shall not
stop the motor when the fault is issued.
A Fault Warning message will remain as long as the fault
condition is active. When the condition clears the Fault
Warning message is removed. A Fault Warning reset is not
required. There are five protection Fault Warnings that will
change to Fault Trip status if the RUN command is active
during the time in which Fault Warning occurs.
●
Backspin
●
Undervoltage
●
Overvoltage
●
Voltage Imbalance
●
Starts Per Hour
All other protections have Fault Trip parameters that may be
enabled or disabled. Any parameter set to Fault and Fault No
Trip will require a reset when the trip condition occurs. Fault
Trip parameters may be configured to enable an automatic
restart when the Fault Trip condition clears or is reset. Motor
status will indicate a Fault trip or Fault Warning condition.
Then the Active Fault and Active Inhibit registers will indicate
the reason for the motor stop.
Fault Trip and Fault No Trip are both written to the fault
queue and both appear in the Fault Snapshot. Warnings
are not written to the queue or the snapshot.
Register 312: Active Fault will indicate faults that must be
cleared. Both user interface families will indicate a fault or
warning condition is present with the FAULT/WARN LEDs.
The C445UM monitoring user interface will also immediately
provide a complete fault description with access to the trip
snapshot and fault queue.
Note:
Register 312: Active Fault and Value 25:
Communication Loss on Active Fieldbus, may be
configured to stop the operation of the C445 but not
cause a fault. In this case when communications
resume, the C445 will not need to be reset.
This behavior can also be modified in the user
interface by going to PRG
R
Operation Mode
R
Comm Loss Behavior and Comm Idle Behavior.
Motor Control Operation
The Base Control Module monitors the motor during periods
of normal operation (see
Table 23
). Normal operation
includes the Start cycle, Run cycle, and Stop cycle. A Fault
Trip event prior to the RUN command will prevent a motor
start. A Fault Trip event during the Start cycle will abort the
Start attempt, and a Fault Trip event during RUN will cause a
motor coast-to-stop. For example, the mains voltage may dip
due to the starting load imposed by the motor Start cycle. If
the dip causes a Fault Trip, the Start cycle will be aborted and
the motor will coast-to-stop.
Note:
The thermal overload and residual ground fault
functions are active at all times.
Start Cycle and Transition Timing
Motor Start, Motor Stop, and Motor Transition parameters
are used by the C445 to recognize modes of operation for
protection functions. The Transition Threshold does not
control any external devices, but only changes protection/
operation parameters based on Start or Run profiles. The
following figure shows an example of how the C445
recognizes the stages in a normal operating-cycle current
profile. Initially, the motor is stopped and the current is zero.
As long as the C445 is not in a Fault Trip condition, it will
permit contactor energization by closing its trip contact in
series with the contactor coil. The contactor can be
energized by the operator or by a Modbus command. The
C445 recognizes a motor Start when it measures motor
current exceeding 30% of the FLA setting. A motor Stop is
recognized when the current falls below 5% of FLA. During
the Start cycle the C445 detects a transition point, when the
large starting currents have fallen below a transition level.
The parameters that control the transition profile are defined
below.
Note:
The C445 transition from the Start cycle to the Run
cycle is based on set time or current value, whichever
occurs first.
Note:
The start cycle time limit is also used as the stall
inhibit time. See Stall protection for details.
