GE AKR-30 Series Maintenance Manual page 155

SECTION 1 4-MicroVersaTrip® Plus and M icroVersaTrip® PM Trip U nits
The MVT-Pius/MVT-PM is a sol id-state d i rect-acting
self-powered trip device system . The system consists of
the MVT- Plus/MVT- PM programmer, current sensors and
a flux sh ifter trip device. Figure 1 1 0 shows location of
features on programmer. See user manual GEH -5891 A.
1 4.1 TRIP UNIT
MicroVersaTrip® Plus Trip Unit
M icroVersaTrip® Plus trip un its util ize a digital , LCD
display with a four-button keypad to provide local set-up
and readout of tri p settings. A 3-phase ammeter and trip
ind icators are standard, as is a clear plastic cover with
provisions for seal ing to allow tamper resistant instal la­
tion. The trip unit digital ly measures the current waveform
in each phase to determine the true RMS value of the
current, regardless of the waveshape. MicroVersaTri p®
Plus tri p units provide accurate, pred ictable overload and
short circuit protection for d istri bution systems that in­
clude ac and de variable speed d rives, rectifiers, ind uction
heating, and other loads that cause high harmonic distor­
tion as well as standard circuit. They provide maxi mum
breaker-to-breaker selectivity and custom load protec­
tion. Short time and g round fault functions include the
flexibility of coordination with or without an l2t ramp and
are also avai lable with high range instantaneous.
MicroVersaTrip® PM Trip Unit
The M icroVersaTrip® PM trip unit adds power manage­
ment system capability, advanced metering, and protective
relays to the basic functions of the MicroVersaTri p® Plus.
MicroVersaTrip® PM tri p units communicate d i rectly on
the G E POWER LEADER'" com mun ications bus.
FIG. 1 1 0
Power Requirements
A small amount of power is necessary to energize the
liq uid crystal disp lay (LCD) during setup , for viewing
breaker status, and for metering d isplays. MicroVersaTrip®
PM trip units require external 24 Vdc control power for
operation . The four sources of such power are the
following.
•
Flow of current - Breaker current sensors provide
sufficient power to energize the LCD when at least
20% of the sensor's ampere rating is flowing.
•
24 Vdc control power-
PM tri p units are supplied with external 24 Vdc power
that, whenever present, energizes the LCD. Some
breaker models that are configured for MicroVeraTri p
Plus trip un its may b e optionally equ i p ped t o accept
an external 24 Vdc supply.
•
Micro VersaTrip Test Kit -
Kit, Cat No. TVRMS, contains a 24 Vdc power supply.
The LCD is energized whenever the test kit jack is
pl ugged into the test receptacle on the rating plug.
•
Micro Versa Trip battery pack
M icroVersaTri p® battery pack contains a 24 Vdc power
source and a jack. The LCD is energized when the
jack is plugged into the rating p lug test receptacle.
Breakers with M icroVersaTrip®
The MicroVersaTrip@ Test
- T h e p o rt a b l e
77