GE AKR-30 Series Maintenance Manual page 159

SECTIO N 1 4-MicroVersaTrip® Plus and M icroVersaTrip® PM Trip Units
1 4.6 NEUTRAL C U RRENT SENSORS
CAUTION: Neutral current sensors are req uired for three­
phase, four-wire systems . When the trip u n it is con nected
to a three-phase, three-wire system, the neutral sensor
termi nals are left open. Do not short any neural current
sensor terminals in a three-phase, three-wire system , as
this could result in damage to or malfunction of the
electrical system .
F i g . 1 1 8 shows t h e neutral sensor. The neural sensor is
requ i red when i ntegral g round fault protection is used on
single phase-three wire or three phase-four wire systems.
It is i nserted into the neutral cond uctor and therefore is
separately mou nted in the cable or bus compartment.
The outputs of the phase sensors and neutral sensor
are connected to a programmer circuit which sums these
values. The total value will remain zero as long as there is
no g round current flowing.
The neutral sensor is an electrical d u plicate of the phase
sensor. Therefore, when phase sensors are chang ed , the
neutral sensor must be correspondingly be changed.
FIG. 1 1 8 TYPICAL N EUTRAL SENSOR
1 4.7 RATING PLUG REMOVAL AND RE­
PLACEMENT
CAUTION: Removal of the rating plug while the breaker
is carrying current reduces the breaker's current-carrying
capacity to approxi mately 2 5 % of the current sensor
rating.
I nterchangeable rating plugs are removed with a Rating
Plug Extractor, Catalog No. TRTOOL. (Suitable equiva­
lents are commercially available as "integ rated circuit
(DI P) extractors . ") Grasp the rating plug tabs with the
extractor and pull the plug out. Be sure to grab the tabs
and not the front cover of the rating plug , or the plug may
be damaged.
Rejection features are provided on all rating plugs to
prevent appl ication mismatches. Never force a rating
plug i nto place. Refer to Table 1 6 to find the appropriate
rating plugs for each sensor rating and breaker frame.
If a replacement rating plug has a d i fferent rating than
the plug that was removed , follow the appropriate setup
procedure GEH -5891 A to enter the new rating.
Do not attempt to use a rating plug from a Spectra RMS
breaker or a MicroVersaTri p® Plus or M ic roVersaTrip"'
P M Trip U n it.
TABLE 1 6
Sensor
Cat. No. Rating, Amps
TR4B 1 50
TR4B200
TR4B225
400
TR4B250
TR4B300
TR4B400
TR8 B300
TR8 B400
TR8B450
TR8B500 800
TR8B600
TR8B700
TR8 B800
TR1 6 B600
TR1 6 B800
TR1 6 B 1 000
1 600
TR1 6 B 1 1 00
T R 1 6 B 1 200
TR1 6B1 600
TR20B750
TR20B800
TR20B1 000
TR20 B 1 200 2000
TR20 B 1 500
TR20B1 600
TR20 B2000
Plug Breaker
Rating Frames
1 50
200
AKR30,
225
AKR30H,
250
AKR30L
300
400
300
400
AKR30,
450
AKR30H ,
500
AKR50S,
600
AKR50H
700
800
600
800
1 000 AKR50,
1 1 00 AKR50H
1 200
1 600
750
800
1 000
1 200 AKRT50H
1 500
1 600
2000
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