MicroVersaTrip Plus™ and MicroVersaTrip PM™ Trip Units
Chapter 5. Maintenance and Trouble-Shooting
35
SS
SS
yy
yy
mm
mm
pp
pp
tt
tt
oo
oo
mm
mm
PP
PP
oo
oo
ss
ss
ss
ss
ii
ii
bb
bb
ll
ll
ee
ee
CC
CC
aa
aa
uu
uu
ss
ss
ee
ee
CC
CC
oo
oo
rr
rr
rr
rr
ee
ee
cc
cc
tt
tt
ii
ii
vv
vv
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AA
AA
cc
cc
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ii
oo
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nn
nn
1. The Trip Unit display is
blank.
Line current is below 20% of
the breaker sensor rating
(MicroVersaTrip Plus).
External +24 Vdc is absent
(MicroVersaTrip PM).
At least 20% of the current sensor rating,
xCT
, must
be flowing through the breaker to activate the display.
If not, power the Trip Unit with the internal battery
or the Portable Power Pack. The battery power supply
is disabled when any current is sensed through the
current sensors.
Check that the control power supply is present and
operational.
2. The Trip Unit display
flashes.
Can occur on Plus-style Trip
Units when the load current
fluctuates near 20% of the
breaker sensor rating.
Power the Trip Unit with the internal battery or the
Portable Power Pack.
3. The Trip Unit display
flashes ERR.
The built-in self test has
detected an error.
Replace the Trip Unit.
4. The trip indication
target will not clear.
Trip Unit is not in Status
mode.
Press FUNCTION until STATUS is displayed. Hold
down the VALUE key and press the SELECT key to
clear the target.
5. Unit does not com-
municate with the
Monitor, POWER
LEADER Distribution
Software, or FPU.
The commnet wires are
shorted or improperly
connected.
FPU version is lower than 2.0.
The Trip Unit address is
incorrect.
Locate and repair the short or the incorrect con-
nection.
Update the FPU to version 2.0 or higher.
Check that the address assigned to the Trip Unit, as
in Chapter 2, agrees with the address at the host.
6. Current readings are
incorrect.
The rating plug value was
defined incorrectly.
Read the
X
value from the rating plug name plate
and enter this as the
xIn
value with the rating plug
current set point procedure in Chapter 2.
Do not
enter the sensor rating, S.
7. Voltage readings are
incorrect.
The potential transformer
(PT) primary voltage was
defined incorrectly.
The PT connection was
defined incorrectly.
Read the PT primary rating from the PT name plate
and enter this value with the PT primary voltage
procedure in Chapter 2.
Follow the PT connection procedure in Chapter 2 to
enter Ph-N for a wye-connected PT primary or Ph-Ph
for a delta-connected PT.
8. The display is blank or
the Low Battery symbol
appears when the
BATTERY key is pressed.
The battery is discharged.
The battery was stored too
long with no power applied to
the Trip Unit
Replace the battery.
Power the Trip Unit with external power or by
energizing the breaker for several days to freshen the
battery.
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