Isolation monitoring in IT-systems Isolation monitoring device / Earth

Isolation monitoring in IT-systems Isolation monitoring device / Earth
Isolation monitoring in IT-systems
Isolation monitoring device /
Earth-leakage monitor
The IT system with additional equipotential bonding and isolation monitoring equipment
The IT system is supplied either from an isolation transformer or an
independent voltage source, such as a battery or a generator.
In this system no active conductor is directly connected to earth
ground.The advantage of this is that only a small fault current can
flow in the event of an insulation fault. This current is essentially
caused by the system's leakage capacitance.
The system's fuse does not respond, thus maintaining the voltage
supply - and therefore operation - even in case of a phase-to-earth
fault.
The insulation monitoring device recognizes insulation faults as they
develop, and reports that the value has fallen below the minimum
immediately. This prevents an interuption of power set point caused
by a second more severe insulation fault.
The following illustration shows the typical arrangement of an IT
system.
In IT-N systems additionally the secundary side star point of the
transformer is used as neutral.
1SVC 110 000 F 0459
Measuring and
monitoring relays
The high reliablitity of an IT system is guaranteed thanks to
continuous insulation monitoring.
Insolation
monitoring device
e.g. CM-IWN-AC
additional equipotential
bonding
Application and connection examples CM-IWN AC in IT- and IT-N systems
PE = earth ground conductor
CM-IWN-AC
1SVC 110 000 F 0702
three-phase IT- system
CM-IWN-AC
1SVC 110 000 F 070 1
single-phase IT-N system
CM-IWN-AC
1SVC 110 000 F 0700
three-phase IT-N system
Isolation resistance and
earth-leakage monitor CM-IWN-AC
Ordering details
e
d
c
CM-IWN-AC
a Selector switch
b Response value 1-110kΩ,
c Green LED - supply voltage
d Red LED - state of relay
e Button "Test" - Reset
2 measuring ranges from
1-110kΩ
Manual reset feature
Suitable for insulation
monitoring of single phase
or three phase mains
Function
The CM-IWN-AC is used to monitor the insulation resistance of single-phase or three phase AC supply voltages.
It is primarily used to monitor auxiliary circuits that are electrically isolated from supply voltage circuits.
The CM-IWN-AC monitors insulation resistance between ungrounded AC supply voltages and grounded
conductors. A superposed DC measuring voltage is used for measurement.
Error storage
The tripped state can be stored by connecting terminals S1, S2. Remote reset can be added by
connecting a push-button (n/c contact) in series with S1 and S2: pressing the button resets the unit.
Attention
The CM-IWN-AC is designed for AC supply voltages. Rectifiers, that are connected in series, should be
electrically isolated from the CM-IWN-AC.
Tripping time
1 Function
Supply
A1/A2;
A1/B2
S1/S2
Spring contact
Store,Reset
Front fitted button
or remote button
Reset,
S1/
Check
Isolations resistance R
of the supply
Set response
1,6xRx
value
Rx
c/o contact
15/18
15/16
tT-Test >approx. 300ms
Type
Supply voltage
CM-IWN-AC
24-240VAC/DC
110-130V, 220-240VAC
Order code
Pack. unit
piece
1SVR 450 075 R 0000
1SVR 450 071 R 0000
1
1
Performance check with
front mounted test button or
remote test button
1c/o contact/
opened circuit principle
tA = delay time
Rim = measured isolation resistance
Ris = adjusted isolation resistance
RS 442-9281
Error display by LED
Approvals
,
,
The voltage is supplied via terminals A1-A2 (A1-B2).
This can be the voltage supplied from the mains to be
monitored. The CM-IWN superimposes a phase or neutral
.
(if available) on a DC-voltage between terminals L and
In case of a fault the resistance of the mains to earth
decreases. The resulting earth-leakage current flow is sensed by the unit. When the earth-leakage current exceeds
the set response value, the output relay energizes with delay
(see characteristic) and the red "fault" LED lights.
1SVC 110 000 F 0461
Acc. to VDE 0413 part 2
Operating principle
Examples of use
The earth-leakage monitor CM-IWN-AC is mainly used in
industrial applications with electrically isolated AC-mains
for the measurement of a first isolation fault.
Thus the installation is protected from incorrect operation
caused by an eventual second isolation fault.
Both resistances R1 and R2 correspond to two subsequent
isolation faults (see drawing). When K1 opens, current
continues to flow through R1, , and R2 and K2 will remain
energized.
This incorrect operation may lead to a considerable damage
to the installation or the operator.
Remark: 1c/o = SPDT; 2c/o = DPDT
1SVC 110 000 F 0703
LED to indicate supply
voltage ON
Measuring and
monitoring relays
b
Test
An insulation fault can be simulated with the front mounted "Test" button.
A remote test button can be connected via terminals S1- . Tripping is caused by opening a n/c contact.
1SVC 110 000 F 0737
a
1SVC 110 000 F 0736
1SVR 450 075 F 0000
The CM-IWN-AC is designed for an insulation resistance range of 1...110 kΩ in 2 ranges. The desired
range - 1...11 kΩ and 10...110 kΩ - is set with a front mounted switch.
The setting range switch helps to adapt the IWN to most application requirements.
The output relay energizes and the yellow LED lights up as soon as insulation resistance is 0.9x of the set
response value and resets as soon as insulation resistance exceeds 1.6 times the response value.
Isolation resistance and Earth leakage monitors
Technical data and standards / directives
Input circuit
Supply voltage - power consumption
24-240VAC/DC
110-130VAC
220-240VAC
Tolerance of the supply voltage
Supply voltage frequency AC/DC
Supply voltage frequency AC
Duty cycle
A1-A2
A1-B2
A1-A2
Measuring and
monitoring relays
Measuring circuit
Monitoring function
Measuring range, threshold value min-max.
Internal resistance min.
AC current internal resistance min.
DC current internal resistance min.
Test resistance
Max. isolation voltage (L-PE)
Measuring DC voltage max.
Cable length for delete- check button max.
Delay time
Display of operating status
Supply voltage
Isolation fault
Output circuits
No. of contacts
Operational principle 1)
Contact material
Rated voltage acc. to VDE0110, IEC664-1, IEC947-1
Switching voltage min.
Switching voltage max.
Switching current min.
Utilzation categories acc. to IEC60947-5-1, EN60947-5-1
Rated switching current AC12 (resistive)
230V
Rated switching current AC15 (inductive)
230V
Rated switching current DC12 (resistive)
24V
Rated switching current DC13 (inductive)
24V
Max. mechanical life
Max. electrical life (acc. to AC12, 230V, 4A)
Short circuit proof, max. fuse rating
n/c contact
n/o contact
General Data
Width of enclosure
Wire size
Weight
Mounting position
Degree of protection housing / terminals
Operating temperature
Storage temperature
Mounting
Standards / directives
Product standard
Electromagnetic compatibility
EMC-tests acc. to EN50082-2
ESD acc. to IEC61000-4-2, EN61000-4-2
HF radiation resistance acc. to IEC61000-4-3, EN61000-4-3
Burst acc. to IEC61000-4-4, EN61000-4-4
Surge acc. to IEC61000-4-5, EN61000-4-5
HF line emission acc. to IEC61000-4-6, EN61000-4-6
Low voltage directive
Vibration resistance acc. to IEC 68-2-6 Fc
Operating safety
Environmental tests acc. to IEC68-2-30 Db
CM-IWN-AC
CM-IWN-DC
approx. 8VA/2W
approx. 3VA
approx. 3VA
approx. 8VA/2W
-15%...+10%
15-400Hz or DC
50-60Hz
100%
isolation monitoring resistive
isolated AC mains
isolated DC mains
1-11kΩ, 10-110kΩ
10-110kΩ
57kΩ
100kΩ
100kΩ
820Ω
415VAC
300VDC
30VDC
24-240VDC
10m
see page ordering details
<1s at isolation, <0.9x response value
green LED
red LED / output relay energized
open-circuit principle
green LED
error L+ red LED, error L- red LED
15-16/18
1c/o contact
open- or closed-circuit principle, selectable
AgCdO
250V
400VAC, 300VDC
5A
3A
5A
2A
30 x 106
0.1 x 106
4A fast, operating class gL
6A fast, operating class gL
45mm
2x2.5mm2 (2x14 AWG) stranded with wire end ferrule
approx. 300g
any
IP50 / IP20
-25°C...+65°C
-40°C...+85°C
DIN rail (EN50022)
IEC60255-6, EN60255-6
89/336 EWG, 91/263 EWG, 92/31 EWG, 93/68 EWG, 93/67 EWG
level 3 - 6kV/8kV
level 3 - 10 (3)V/m
level 3 - 2(1)kV / 5kHz
level 3 - 2(1)kV L-L
level 3 - 10(3)V
93/68/EWG
mechanical resistance 10G, f = 55Hz, a = 0.95mm, t = 2h per level
4G
24h cycle, 55°C, 93% rel., 96h
Approvals
cULus, GL, GOST
Isolation data
Rating acc. to HD625.1 S1, VDE0110, IEC664-1, IEC60255-5
Rated isolation voltage between supply, meas. and output circuits
Rated impulse withstand voltage between all isolated circuits
Test voltage between all isolated circuits
Pollution category
Overvoltage category
250V
4kV / 1.2 - 50µs
2.5kV, 50Hz, 1 min.
3
3
1)
Open-circuit principle: Output relay energizes when the set threshold value is exceeded or passes below the measured value
Closed-circuit principle: Output relay de-energizes when the set threshold value is exceeded or passes below the measured value
Remark: 1c/o = SPDT; 2c/o = DPDT
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