5–44 MM300 MOTOR MANAGEMENT SYSTEM – INSTRUCTION MANUAL
PROTECTION ELEMENTS CHAPTER 5: SETPOINTS
could be set to “70%” and the Undercurrent Alarm Level to “75%”. The Undercurrent Trip
Delay
and Undercurrent Alarm Delay setpoints are typically set as quick as possible (that is,
1 second).
NOTE:
This protection function can be bypassed while the device is in Test Mode. This feature is
available by setting the setpoint 'PRT Func Ignore in Test Mode' to Enabled.
Underpower
protection
Underpower protection is available whether or not a type I0_B module (3 x VT) is included
in the order code. When this option is included, the power is calculated using the voltages
connected to this card. When this option is not included, the power is calculated using the
auxiliary voltage and assumes that the missing voltages are balanced.
When the motor is in the running state, a trip or alarm will occur if the magnitude of the
real power falls below the pickup level for the time specified by the
Underpower Alarm
Delay
setpoint. The pickup levels should be less than the lowest motor loading during
normal operations.
Setpoint levels are a percentage of MNR, where MNR is the "Motor Rating Setpoint."
The following setpoints are available for the underpower protection feature.
Underpower Trip Level
Range: 1 to 100% MNR in steps of 1 or OFF
Default: OFF
This setpoint specifies the underpower trip pickup level. A value of “OFF” disables the
underpower trip function.
Underpower Trip Delay
Range: 1 to 60 seconds in steps of 1
Default: 1 second
The setpoint specifies the amount of time the motor power must meet or exceed the trip
pickup level to generate a trip.
Underpower Alarm Level
Range: 1 to 100% MNR in steps of 1 or OFF
Default: OFF
This setpoint specifies the underpower alarm pickup level. A value of “OFF” disables the
underpower alarm function.
Underpower Alarm Delay
Range: 1 to 60 seconds in steps of 1
Default: 1 second
The setpoint specifies the amount of time the motor current must exceed the alarm
pickup level to generate an alarm.
For example, underpower may be used to detect loss-of-load conditions. A loss-of-load
condition will not always cause a significant loss of current. Power is a more accurate
representation of loading and may be used for more sensitive detection of load loss or
pump cavitation. This may be especially useful for detecting process related problems.
NOTE:
This protection function can be bypassed while the device is in Test Mode. This feature is
available by setting the setpoint 'PRT Func Ignore in Test Mode' to Enabled.
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