Power Break
®
Circuit Breakers
Chapter 2. Breaker Operation
7
All breakers provided with tap cards are shipped with both
HIGH
(100% of the current rating
Sensor Amp
on the
breaker name plate) and
low
(50–75% of the current
rating
Sensor Amp
on the breaker name plate). The
low
card is packed and supported on the breaker handle. The
high
card is installed in the breaker frame. To change
settings use the following procedure:
W
W
W
WA
A
A
AR
R
R
RN
N
N
NIIIIN
N
N
NG
G
G
G:::: The circuit breaker must be removed from
the electrical system before attempting any operations
that involve removing the breaker’s cover.
1
1
1
1.... Turn the breaker
off
.
2
2
2
2.... Remove the four cover mounting screws and remove
the top cover. On motor operator-equipped breakers,
remove only the top cover.
3
3
3
3.... Withdraw the card from the tap changer support and
replace with the other card, as shown in Figure 10.
The print on the top of the card should be oriented
the same as the breaker cover name plate.
Figure 10. Cover and trip unit removed from the breaker.
4
4
4
4.... Trip units providing ground fault protection must
also have the tap setting changed on the tapped neu-
tral CT (four-wire systems). Change the black wire
lead from the
high
or
low
terminal to match the
desired tap setting of the breaker frame, as shown in
Figure 11.
5
5
5
5.... Replace the breaker cover.
6
6
6
6.... Operate the breaker manually through the
charge–close–open
cycle to ensure that the breaker is
properly functioning mechanically before energizing
or connecting it to the electrical system.
N
N
N
NO
O
O
OT
T
T
TE
E
E
E:::: A deenergized undervoltage release will not allow
the mechanism to charge and close.
7
7
7
7.... Store the extra tap card in a convenient place.
Figure 11. Neutral CT connection for four-wire ground fault.
Neutral Current Transformer (Four-Wire Ground
Fault System)
Ground fault protection is offered as an optional function
of the MicroVersaTrip® trip unit. However, all MicroVer-
saTrip-generation breaker frames are provided with ter-
minal board points for connection to a neutral CT.
D o
not short these terminals if there is no neutral CT
connected.
Always match the rating of the CT to the rating of the cir-
cuit breaker; specifically, use the following criteria:
•
Fixed-rated breaker frames – match the neutral CT
amp rating to the breaker sensor amp rating.
•
Tapped or high/low-rated breaker frames – match
the neutral CT amp rating to the
high/low
setting of
the breaker sensor amp rating.
Note that MicroVersaTrip RMS-9-equipped breakers are
not available with inverted construction (formerly desig-
nated by Cat. No. suffix B). These breakers may be either
top fed, as illustrated in Figure 12, or bottom fed, as illus-
trated in Figure 13.
N
N
N
NO
O
O
OT
T
T
TE
E
E
E:::: The neutral CT is mounted in reverse in Figure
13 when the breaker is bottom (reverse) fed.
C
C
C
CA
A
A
AU
U
U
UT
T
T
TIIIIO
O
O
ON
N
N
N:::: Match the tapped terminal for the black lead
to the tap setting, if provided, on the breaker frame.
C
C
C
CA
A
A
AU
U
U
UT
T
T
TIIIIO
O
O
ON
N
N
N:::: Observe the polarity markings on the neutral
CT shell and the breaker frame.
C
C
C
CA
A
A
AU
U
U
UT
T
T
TIIIIO
O
O
ON
N
N
N:::: When a neutral CT is not used or not
required (three-wire ground fault),
do not short the
ground fault terminal points on the breaker frame.
Leave them open as supplied by the factory.
Summary of Contents for Power Break
Page 1: ...g Power Break Circuit Breakers 800 2000 A Frames 240 600 Vac GEH 4693D User s Guide ...
Page 2: ......
Page 27: ......
