SECTION 1 4-MicroVersaTrip® Plus and MicroVersaTrip® PM Trip Units
1 4.6 NEUTRAL CURRENT SENSORS
CAUTION:
Neutral current sensors are required for three
phase, four-wire systems. When the trip unit is connected
to a three-phase, three-wire system, the neutral sensor
terminals 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.
Fig. 1 1 8 shows the neutral sensor. The neural sensor is
required when integral g round fault protection is used on
single phase-three wire or three phase-four wire systems.
It is i nserted into the neutral conductor and therefore is
separately mounted 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 18 TYPICAL NEUTRAL 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 approximately 25% 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 "integrated 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 application mismatches. Never force a rating
plug into 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 different 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 MicroVersaTrip® Plus or M icroVersaTrip"'
PM Trip U n it.
TABLE 1 6
Sensor
Plug
Breaker
Cat. No.
Rating, Amps
Rating
Frames
TR4B1 50
1 50
TR4B200
200
AKR30,
TR4B225
400
225
AKR30H,
TR4B250
250
AKR30L
TR4B300
300
TR4B400
400
TR8B300
300
TR8B400
400
AKR30,
TR8B450
450
AKR30H,
TR8B500
800
500
AKR50S,
TR8B600
600
AKR50H
TR8B700
700
TR8B800
800
TR1 6 B600
600
TR1 6B800
800
TR1 6B1 000
1 600
1 000
AKR50,
TR1 6B1 1 00
1 1 00
AKR50H
T R 1 6 B 1 200
1 200
TR1 6B1 600
1 600
TR20B750
750
TR20B800
800
TR20B1 000
1 000
TR20B 1 200
2000
1 200
AKRT50H
TR20B1 500
1 500
TR20B1 600
1 600
TR20B2000
2000
81
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