MicroVersaTrip Plus™ and MicroVersaTrip PM™ Trip Units
Chapter 1. Introduction
6
1-6 Equipment Interfaces
MicroVersaTrip Plus Trip Units
MicroVersaTrip Plus Trip Units do not usually
require connections within the equipment, since all
wiring is contained within the circuit breaker. The
only two connections are for optional zone-selective
interlock (Z1 and Z2), made by secondary discon-
nect, and the neutral sensor, which uses a special
dedicated disconnect.
Zone-selective interlocking coordinates breakers, so
that the downstream breaker is allowed the first
opportunity to clear a disturbance. The two types of
available zone-selective interlocking are Z1, which
reacts only to ground faults, and Z2, which reacts to
both ground faults and short-time overcurrent pick-
ups.
Neutral Current Sensors
C
C
C
CA
A
A
AU
U
U
UT
T
T
TIIIIO
O
O
ON
N
N
N:::: Neutral current sensors are required for
single-phase, three-wire and three-phase, four-wire
systems. When the Trip Unit is connected to a three-
phase, three-wire system, the neutral sensor
terminals of the breaker are left open. Do not short
any neutral current sensor terminals in a three-
phase, three-wire system, as this could result in dam-
age to, or malfunction of, the electrical system.
A
A
A
AT
T
T
TT
T
T
TE
E
E
EN
N
N
NT
T
T
TIIIIO
O
O
ON
N
N
N:::: Un transformateur de courant de
neutre est nécessaire pour les réseaux 3
neutre. Si le neutre n’est pas distribué, les bornes de
neutre du déclencheur doivent être laissées ouvertes.
Ne pas les court-circuiter (ceci peut endommager le
d é c l e n c h e u r e t e n t r a i n e r u n m a u v a i s
fonctionnement du système électrique.
MicroVersaTrip PM Trip Units
In addition to the inputs received by MicroVersaTrip
Plus Trip Units, MicroVersaTrip PM Trip Units also
receive inputs from external voltage conditioners, a
+24 Vdc control power supply, and communication
connections. Ex24 Vdc control power is
required for operation.
RMS9C-type MicroVersaTrip PM Trip Units require
a connection to an auxiliary switch within the
breaker that senses the breaker position. This
connection is not required for RMS9D-type
MicroVersaTrip PM Trip Units used on Power
Break® II breakers.
POWER LEADER™ Communication Network
The POWER LEADER Communication Network
(commnet) transmits data and instructions between
the Trip Unit and an external intelligent device. The
external device may be the POWER LEADER system,
the Epic system, or a POWER LEADER Monitor.
Devices on commnet may be up to 1000 feet apart
without signal repeaters, subject to certain con-
straints. A maximum of 30 devices can be connected
without a signal repeater. Refer to GEH-5943 for
installation and operation of the POWER LEADER
system.
Commnet connections are made directly to wiring
terminations on breaker frames. All commnet con-
nections to the Trip Units are made through the 36-
pin or 50-pin plug on the Trip Unit, which mates
with a receptacle on the breaker frame. These addi-
tional connections are made to the equipment
through the secondary disconnects of the breaker.
Voltage Inputs
Voltage inputs are sensed by conventional instru-
ment potential transformers(PTs). PTs have 120 Vac
secondaries and must always be used in groups of
three; no open-delta connections are permitted. PT
primaries are connected either line-to-line or line-to-
neutral, as required.
PTs may be used for other monitoring functions,
subject to reasonable burden limitations. Note that
PTs must be connected in a specific sequence to
ensure proper phase relations and power-flow sens-
ing.
Each PT output feeds an individual voltage condi-
tioner that scales the nominal voltage to approxi-
mately 1.76 Vac for use by the Trip Unit.
