Order No.: 3ZX1012-0NJ60-1AA1
3
SENTRON
Electronic Fuse Monitoring EFM 20/25
3NJ69
EN 60 947 / IEC 60 947
Operating Instructions
English
The electronic fuse monitoring (EFM) is eitheralready installed in the 3NJ62 or it
is an accessory which must be installed by the customer in the corresponding
3NJ62 in-line fuse switch disconnector (see EFM installation)
.
The fuse monitoring functions with its own power supply via the phases. The
LCD display indicates that the voltage supply to the EFM is ensured.
The fuse monitoring records, signals and displays the states of the fuses. The
EFM operates according to the closed-circuit principle (presettings), which
means that the signaling relay is picked up if there is no fault.
Fuse faults are detected by measuring the voltage upstream and downstream
from the fuse. If the voltage drop falls below a voltage of approximately 13 V
with AC or approximately 20 V with DC at any one of the fuses, the fuse monitor
trips, i.e. the relay opens and the display indicates the affected fuse.
The LCD display of the signaling relay indicates the current status of the fuses
(presettings) and/or the line monitoring. With active line monitoring,
the voltages are monitored for the voltage limits. If one of the voltages is below or
above the limit, then relay 2 drops out (with closed-circuit principle). Undervoltage or
overvoltage is displayed. In the case of faults, the relays react according to the set
operating principle after the set fault suppression time (Del). The memory function
can be activated via the Setup functions. Every message must then be
acknowledged, even if the message is no longer pending. If several messages are
pending, only the message with the highest priority is displayed. A message
signaling a faulty fuse has the highest priority. (see message priorities)
EFM is suitable for 3-phase, sinusoidal AC networks (50 / 60 Hz) or for DC
networks. In connection with an EFM, the 3NJ62 switch disconnector with fuses
may only be used to ensure safe isolation in the following networks:
• in networks with neutral point grounding up to 480 V AC
• in networks without neutral point grounding and one-sided grounding up to
277 V AC
• in 1-phase networks without grounding up to 220 V AC/DC
• in 2-phase networks with grounding up to 440 V AC/DC
Signaling relay 1
1 changeover contact for fuse monitoring only
Signaling relay 2
1 changeover contact as output for group fault messages
OR as signaling relay 1 (presettings)
Capacity of the signaling relay
Relay 1
Relay 2
Short-circuit protection: max. fuse DIAZED 2 A gLgG
Message priorities
Apparent power consumption
S approx. 2.5 VA
Internal resistance of the measuring circuit
Rin > 6 MOhm
Storage temperature
–20 °C to +80 °C
Operating temperature
–5 °C to +55 °C
Operating temperature (from 500 V or 500 A)
–5 °C to +35 °C
Degree of protection with closed
in-line fuse switch disconnector
IP40
Rated operating voltage
of the main switching devices
230 – 690 V AC, 50 / 60 Hz
Voltage limits
+/– 15 %
Undervoltage
375 V
Overvoltage
425 V
Voltage drop for faulty fuse:
> 13 V
Delay time
0.1 s
Relay 2:
as relay 1 (fuse monitoring)
Memory function
off
Open-circuit/closed-circuit current
Closed-circuit current principle
Mode
Run mode
Menu item:
Display of the voltage values / messages
Rated operating voltage
of the main switching devices
220 – 440 V DC
Voltage limits
+/– 15 %
Presettings:
Undervoltage
200 V
Overvoltage
240 V
Voltage drop for faulty fuse:
> 20 V
Delay time
0.1 s
Relay 2:
as relay 1 (fuse monitoring)
Memory function
off
Open-circuit/closed-circuit current
Closed-circuit current principle
Mode
Run mode
Menu item:
Display of the voltage values / messages
Read and understand these instructions before installing,
operating, or maintaining the equipment.
DANGER
Hazardous voltage.
Will cause death or serious injury.
Turn off and lock out all power supplying this device before
working on this device.
CAUTION
Reliable functioning of the equipment is only ensured with
certified components.
1. Description
WARNING
If the display does not light up despite a live infeed and correct
connection of the electronic fuse monitoring, the electronic fuse
monitoring MUST be exchanged immediately.
Signaling relays according to IEC 60947-5-1:
I
th
= 1.5 A
U
imp
= 4 kV
U
i
= 250 V
!
U
e
[V]
24
125
240
DC - 13; I
e
[A]
1
0.2
0.1
AC - 15; I
e
[A]
1.5
1.5
1.5
Priority
Message
Type of function
Comment
1
Phase failure
Line monitoring
Only for AC version. The fault
(phase or fuse failure) which is
first detected in the monitoring
sequence from L1 to L2 to L3 is
displayed.
2
Faulty fuse
Fuse monitoring
DC version: a faulty fuse can only
be detected in a closed circuit.
3
Overvoltage
Line monitoring
—
4
Undervoltage
Line monitoring
—
2. Technische Daten
Technical data - AC version EFM 20 (presettings)
Technical data - DC version EFM 25 (presettings)
12
14
(22)(32) (24)(34)
11 (21)(31)
42
44
(52)(62) (54)(64)
41 (51)(61)