Protection Relays
Voltage Monitoring Relays
HLMU SERIES
Description
The HLMU Series is a universal voltage, encapsulated, 3-phase
voltage monitor. It continuously measures the voltage of each of
the three phases with microcontroller accuracy and compares
the value to preset trip points. It separately senses phase
reversal and loss; over, under and unbalanced voltages; and
over or under frequency. Protection is assured during periods
of large average voltage fluctuations, or when regenerated
voltages are present. The unit trips within 200ms when phase
loss is detected. Adjustable time delays are included to prevent
nuisance tripping and short cycling of sensitive equipment. The
isolated, 10A, DPDT relay contacts trip when a phase voltage
exceeds the trip limits for the trip delay. Nominal line voltage,
voltage unbalance, and time delays are knob adjustable. The
phase loss setpoint and the acceptable frequency range are
fixed. Both delta and wye systems can be monitored; no
connection to neutral is required.
Features & Benefits
Wiring Diagram
L1, L2, L3 = Line Voltage Input
NO = Normally Open Contact
NC = Normally Closed Contact
C = Common, Transfer Contact
CAUTION:
2 amp max. fast acting
fuses are recommended to protect the
equipment‘s wiring. They are not required
to protect the HLMU.
NOTE:
Relay contacts are isolated,
277VAC max.
FEATURES
Proprietary
microcontroller based
circuitry
Universal line
voltage range
DIN rail (35mm) or
surface mounting
LED indication
Encapsulated
Finger-safe
terminal blocks
BENEFITS
Constant monitoring to protect against phase loss,
phase reversal; over, under, and unbalanced voltage;
over and under frequency
Flexibility to work in 200 to 480VAC applications
Installation flexibility
Provides diagnostics of relay, fault and time
delay status
Protects against shock, vibration, and humidity
Meets IEC 61000 safety requirements
Ordering Information
MODEL
OUTPUT
RESTART
FUNCTION
VOLTAGE
UNBALANCE
TRIP
DELAY
RESTART
DELAY
HLMUDLAAA
DPDT
Lockout,
min off
time
No restart
delay
No restart
delay
Staggered
restart
Adjust.
2 - 10%
Fixed, 4%
Adjust.
2 - 10%
Adjust.
2 - 10%
Adjust.
1 - 30s
Fixed, 5s
Adjust.
1 - 30s
Adjust.
1 - 30s
Adjust.
0.6 - 300s
None
None
Adjust.
0.6 - 300s
HLMUDN0405N DPDT
HLMUDNAAN
HLMUDRAAA
DPDT
DPDT
Operation
Upon application of line voltage, the output is de-energized
and the restart delay begins. If all the three-phase voltages are
within the acceptable range, the output energizes at the end
of the restart delay. The microcontroller circuitry automatically
senses the voltage range, and selects the correct operating
frequency (50 or 60Hz). The over and under voltage trip points
are set at ± 10% of the adjusted line voltage. When the
measured value of any phase voltage exceeds the acceptable
range limits (lower or upper) the trip delay begins. At the end of
the trip delay the output relay de-energizes. If the phase voltage
returns to an acceptable value before the trip delay expires, the
trip delay is reset and the output remains energized. Under, over,
and unbalanced voltages plus over or under frequency must be
sensed for the complete trip delay before the unit trips. The unit
trips in 200ms when phase loss or reversal are sensed. The unit
will not energize if a fault is sensed as the line voltage is applied.
Reset:
Reset is automatic upon correction of the voltage or
frequency fault or phase sequence.
Restart Delay Options
L =
Lockout or minimum OFF time. The restart delay begins
when the output trips. The unit cannot be re-energized until the
restart delay is complete. This provides a minimum off time
or lockout time to allow equipment sensitive to short cycling,
Rev: 1-A-062716
If you don’t find the part you need, call us for a custom product 800-843-8848
© 2016 Littelfuse Protection Relays & Controls
www.littelfuse.com/hlmu
www.littelfuse.com/
Protection Relays
Voltage Monitoring Relays
HLMU SERIES
time to reset. If the fault is corrected after the restart delay is
complete, the output energizes immediately. The restart delay
also occurs when line voltage is applied/reapplied.
R =
Restart Delay on fault correction. The restart delay begins
when line voltage is reapplied or when a voltage fault is
corrected. This option is normally selected when staggered
restarting of multiple motors on a power system is required.
N =
No Restart Delay. 0.6 second initialization delay on
application of line voltage applies.
Restart Notes:
All restart options remain reset when the
following conditions are detected:
1.
Phase loss (phase unbalance greater than 25%)
2.
Average line voltage less than 120VAC
3.
Phase reversal
The restart delay begins when the condition is corrected.
LED Operation
The LED flashes green during the restart delay, then glows
green when the output energizes. It flashes red during the trip
delay then glows red when the output de-energizes. It flashes
red/green if phase reversal is sensed. If a fault is sensed during
the restart delay, the LED will glow red during that portion or the
full restart delay.
Undervoltage &
Voltage Unbalance
Type
Overvoltage
Trip Voltage
Reset Voltage
Undervoltage
Trip Voltage
Reset Voltage
Voltage Unbalance
Trip Setpoint
Reset on Balance
Trip Delay
Active On
Range
Tolerance
Restart Delay
Range
Tolerance
Over/Under Frequency
Phase Sequence
Response Time-Phase
Reversal & Phase Loss
Reset
Output
Type
Form
Rating
Life
Protection
Phase Reversal/Failure
Motors and Generators
Surge
Isolation Voltage
Circuitry
Mechanical
Mounting
Dimensions
Termination
Environmental
Operating/Storage
Temperature
Humidity
Weight
Voltage detection with delayed trip &
automatic reset
109 - 113% of the adjusted line voltage
≅
-3% of the trip voltage
88 - 92% of the adjusted line voltage
≅
+3% of the trip voltage
Adjustable 2 - 10% or specify fixed unbalance
of 2 - 10% in 1% increments
≅
-0.7% unbalance
Over/undervoltage, voltage unbalance,
over/under frequency
Adjustable from 1 - 30s or specify fixed
delay 1 - 30s in 1s increments
± 15%
Adjustable from 0.6 - 300s; if no restart
delay is selected a 0.6s initialization
delay applies
± 15%
±4%; Reset ±3%; 50/60 Hz
A, B, C, L1, L2, L3
≤200 ms
Automatic
Isolated Electromechanical Relay
DPDT
10A resistive @ 240VAC;
8A resistive @ 277VAC; NO-1/4 hp @ 120VAC;
1/3 hp @ 240VAC
Mechanical - 1 x 10
6
Electrical (at 10A) - DPDT - 1 x 30
3
ASME A17.1 Rule 210.6
NEMA MG1 14:30, 14:35
IEEE C62.41-1991 Level B
≥ 2500V RMS input to output
Encapsulated
Surface mount with one #10 (M5 x 0.7) screw
Note: 0.25 in.(6.35 mm) spacing between
units or other devices is required
H
76.7 mm (3.0”);
W
50.8 mm (2.0”);
D
41.7 mm (1.64”)
Screw terminal connection up to 12 AWG
(3.3 mm
2
) wire
Accessories
LPSM003ZXID (Indicating),
LPSM003Z (Non-indicating) Fuse Holders
Littelfuse POWR-SAFE Dead Front holders
provide optimum protection to personnel for
Class CC and Midget-Style fuses. 600 VAC/DC
0KLK002.T Midget Fuse (2 Amp)
10 x 38 fast acting, high-interrupting capacity,
current-limiting type fuse. 600 VAC/500 VDC
C103PM (AL) DIN Rail
35 mm aluminum DIN rail available in a 36 in.
(91.4 cm) length.
P1023-20 DIN Rail Adapter
Allows module to be mounted on a 35 mm DIN
type rail with two #10 screws.
Specifications
Line Voltage
Type
Operating Voltage
200 - 480VAC
3-phase delta or wye with no connection
to neutral
Range Voltage Adj. Range Frequency
240
200-240VAC
50 or 60Hz
380
340-420VAC
50Hz
480
400-480VAC
60Hz
550VAC
50/60 Hz automatically detected
≥ 25% unbalance
≤200ms
Line Voltage Max.
AC Line Frequency
Phase Loss
Response Time
-40° to 60°C / -40° to 85°C
95% relative, non-condensing
≅
3.9 oz (111 g)
© 2016 Littelfuse Protection Relays & Controls
www.littelfuse.com/hlmu
www.littelfuse.com/
Rev: 1-A-062716
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