14/1/98 Page 16 Issue H
7.3.12. Undercurrent Setting
This setting determines the pickup upon an undercurrent, this is generally used to protect against an
unloaded machine, e.g. Drive belt failure. A setting of OFF here will disable the feature.
7.3.13. Undercurrent Time
This sets a time between the unit registering an undercurrent level and the actual tripping of the unit.
7.3.14. High Set Overcurrent
This feature is normally enabled when the motor is being controlled by a circuit breaker allowing a
much quicker trip time for high fault currents. A setting of OFF here will disable the feature, it is
recommended that this feature is disabled for fused contactors.
7.3.15. High Set Overcurrent Time
This setting determines the trip time following the measured current exceeding the pickup value.
Note: The High set overcurrent setting is DOUBLED during starting. This feature allows more
sensitive short circuit protection on circuit breaker controlled motors whilst avoiding trips due to the
asymmetrical transient portion of the starting current.
7.3.16 Low Set Overcurrent
This feature allows a quicker trip time for fault currents, or overloads of a medium magnitude. A
setting of OFF here will disable the feature
7.3.17 Low Set Overcurrent Time
This setting determines the trip time following the measured current exceeding the pickup value.
NOTE: The Low set feature is not in service during starting. This feature can therefore be used to
provide a quick operating definite time stall protection once the motor is running.
7.3.19 Set Password
This allows the user to password protect the Relay to avoid unauthorised changing of parameters.
Any four of the pushbuttons may be selected in any order. After pressing <ENTER> the new
password is saved. If you intend to change from the default password, please a make a careful note of
the new password. If you forget the new password, consult your local agent or P&B Engineering for
help on how to restore the default password.
7.3.20 Serial Link Address, RSnn
This setting in the range of 1 to 32 or “OFF” identifies the MPR 3E5 unit to the communications
hardware on the RS485 Data Highway.
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General