Voltage
Monitors
7.10
Low Voltage Products & Systems
1TRC 001 009 C0202
ABB Inc. • 888-385-1221 • Technical assistance 800-377-7722 • www.ssac.com
Accessories
Description
The PLMU Series continuously measures the voltage of each of the three phases to provide protection for
three phase motors and sensitive loads. Its microcontroller senses under and over voltage, voltage unbalance,
phase loss, and phase reversal. Protection is provided even when regenerated voltages are present. Universal
voltage operation and standard base connection allows the PLMU to replace hundreds of competitive part
numbers.
Operation
Upon application of power, a 0.6 s random start delay
begins and the PLMU measures the voltage levels
and line frequency and selects the voltage range. The
output relay is energized and the LED glows green when
all voltages are acceptable and the phase sequence
is correct. LED flashes green during trip delay,
glows red when output de-energizes. Undervoltage,
overvoltage, and voltage unbalance must be sensed
for continuous trip delay before the relay de-energizes.
Re-energization is automatic upon fault correction.
The output relay will not energize if a fault condition is
sensed as three phase input voltage is applied. Line
voltage is selected with the knob, setting the over and
under voltage trip points. Voltage range is automatically
selected by the microcontroller.
See accessory pages for
specifications.
Protects Against: Phase Loss,
Phase Reversal, Overvoltage,
Undervoltage,
& Unbalanced Voltages
Octal Plug-in with SPDT
Isolated 10 A Contacts
Operates from 200 ... 480 V AC
LED Indicator Glows Green
when Voltages are
Acceptable, Red for Faults
Simple 3-Wire Connection for
Delta or Wye Systems
ASME A17.1 rule 210.6
NEMA MG1 14:30, 14:35
IEEE C62.41-1991 Level B
Approvals:
3 Phase Voltage Monitor
PLMU Series
Universal Plug-in Monitor
Connection
F = Fuses
ØA = Phase A = L1
ØB = Phase B = L2
ØC = Phase C = L3NO = Normally Open
NC = Normally Closed
Relay contacts are isolated. Dashed lines are
internal connections.
Panel mount kit
P/N:
BZ1
Octal 8 pin socket
P/N:
OT08PC
3-phase fuse
block/disconnect
P/N:
P0700-241
2 AMP fuse
P/N:
P0600-11
DIN rail P/Ns:
017322005
(Steel)
C103PM
(Al)
Part Number
Voltage Unbalance
Trip Delay
Adjustable 2 ... 10%
PLMU11
Adjustable 0.25 ... 30 s
Available with Fixed Unbalance and Trip Delay
Faceplate View
2 Amp
Fast Acting
Fuses
Recommen-
ded For Safety
(Not Required)
ANSI Device #27/47/59
Ordering Table
PLMU2B01
06.08.04
