Effective 11/2003
Page 23
I.L. 66A7535H02
an associated time delay is adjustable from 0 to 240
seconds with initial factory default of 10 seconds. The time
setting tolerance is +/- 3% or +/- 0.3 seconds whichever is
greater. A difference between Max phase and Min phase
higher than the Amp Unbalance % settings will cause the
breaker to trip with an AMPERES OUT OF BALANCE
message and red Trip LED illuminated in the right corner of
the Digitrip front panel.
This function does require
external auxiliary power to the Digitrip unit.
To avoid
unnecessary operation of this function the breaker must be
carrying 55% of the
I
r rating on at least one phase before it
will trip via Amp Unbalance.
4.2.1.10.2 Phase Loss
The phase loss trip function can be selected in the Pro-
gram Settings - Program Curve Menu
(See Appendix D-
12).
It is set to OFF initially as a factory default. A Time
Delay of 1 to 30 seconds can be selected. If there exists a
75% difference between the Max phase and Min phase
currents and if maintained for the selected time delay, the
breaker will trip with a PHASE LOSS TRIP message and
red Trip LED illuminated in the right corner of the Digitrip
front panel.
This function does require auxiliary power
to the Digitrip unit.
To avoid unnecessary operation of
this function the breaker must be carrying 55% of the
I
r
rating on at least one phase before it will trip via Phase
Loss.
4.2.2 Voltage-Frequency Protection Settings
Voltage and Frequency tripping and/or Alarming can be set
by entering the VOLTAGE menu under the Program
Setting main menu. Please refer to Appendix D-23 for the
trip settings available and Appendix D-16 for the Alarm
settings available. The Alarms can be mapped to Relay A
and the Trips to Relay B and Relay C for desired relay
contact action.
The Voltage (Frequency) function has a master switch
“voltage setting” [enabled/disabled] that can toggle all
voltage related trip and alarm settings. The individual
selections can be enabled or disabled as desired.
NOTE:
When programming the Voltage or Frequency
setting for Trip or Alarm, there exists a setting
interdependancy feature that prevents the user from
making an “over-lapping” under and over value combination.
When this condition is encountered, change the value or
disable the “opposite” setting temporarily to achieve the
desired setting.
4.2.2.1 Voltage, Frequency Protection
These functions, unlike the LSIG Current protection
functions, do require a reliable source of auxiliary
power available on breaker secondary contacts A-14,
A-15.
If the breaker is equiped with the 24-48VDC Power/
Relay Module, the (+) voltage input is terminal A-14.Refer
to the breaker information label for proper trip unit power
voltage and see also Section 1.6 and Appendix C.
The Voltage is sensed on all three phases. Any phase to
phase voltage exceeding the specified setting will activate
the protection function. The voltage sensing points are via
inputs to secondary contacts B-16, B-17 and B-18.
NOTE:
Frequency is sensed on phase A voltage input.The
frequency Trip, Voltage Trip or Alarm function will not be
active if this voltage falls below 70% phase to phase of the
nominal secondary voltage.
4.2.2.2 Voltage, Frequency Trip
Voltage and Frequency Protection Trip functions, if en-
abled, are active whenever the breaker is closed.These trip
functions are made inactive after a trip or when the breaker
opens. The function will be rearmed when the breaker is
reclosed. Observe the cause of trip message after a trip
event then reset the Digitrip by depressing the Reset
pushbutton. At this time observe the real time data of the
parameter that initiated the trip to see if it is still beyond
the specified limit. Voltage and frequency data in the Meter
menu is real time data independent of whether the breaker
is open or closed. Enter the EventLog menu and observe
the event that initiated the trip. When the parameter
returns to within its limits, reclose the breaker if desired.
4.2.2.3 Voltage, Frequency Alarms
These alarms can be enabled by the user by entering the
Program Settings and then the Alarms submenu. Alarms
are real time and are active when the breaker is in either
the open, closed or trip state. The alarm LED will light to
indicate an alarm condition.
NOTE:
If an UnderFrequency or OverFrequency Trip or
Alarm is enabled, the following restriction applies: Trip
units used on 50 Hz systems have valid frequency sensing
range of 43 to 59 Hz. Trip units used on 60 Hz systems
have a valid frequency sensing range of 51 to 70 Hz. All trip
units leave the factory set for 60 Hz. For frequencies
outside the applicable range, the unit will display the
alarm
message “FREQ OUT OF BOUNDS”.
This alarm message also can occur if the system fre-
quency setpoint does not match the nominal power
system frequency. If this message is encountered, check
or change the frequency setting in the System menu. The
FREQ display screen in the Meter sub-menu will display
dashes, “-----“, instead of a numerical frequency.
