ABB ISL-A 24 User manual

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INSTRUCTION MANUAL
ISL-A 24/ ISL-A 48
DEVICE FOR INSULATION PERMANENT CONTROL FOR ISOLATED NETWORKS (IT)
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GENERAL
In IT electrical distribution networks with isolated neutral, the high insulation impedance prevents earth faults
from generating currents that would dangerously elevate the potential of exposed conductive parts.
Therefore, in case of earth leakage in an IT network, it is not necessary to interrupt the supply, but it is still
essential to continually monitor the insulation level in order to detect faults and restore optimal functioning
of the system.
The ISL-C 230 is an Insulation Monitoring Device for IT networks with voltages of 24 to 48 V ac/dc. These de-
vices measure the potential variation of two polarities in reference to earth, to signal when the insulation is
decreasing below a fixed value.
Auxiliary supply is taken from the under-control network. On the front panel, there is signaling for the device
being ON, TEST and RESET push-buttons, and three LEDs for signaling a tripping (TRIP) and to indicate the
polarity of the line under control that has low insulation.
The threshold for trip is regulated by a series of micro-switches. There is a changeover contact relay available
to transfer the information of the low insulation signaling to a remote panel.
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INSTALLATION
The installation must be carried out by qualified and authorized personnel and in the absence of voltage.
Make sure that the instrument is O.K. and has not been damaged during transport.
Make sure that the voltage supply is compatible with the operating voltage of the instrument.
For each independent line, it's possible to use only one control device.
The device is a 3 modules (17.5mm) DIN version with snap on 35mm DIN rail.
It has a sealable transparent front protection cover.
The green LED ON will light up after the connections are set and the instrument is powered on.
DESCRIPTION
1. Green LED ON, signaling the instrument is working.
2. Red LED TRIP, signaling a trip for low insulation; in manual reset
mode, it is necessary to press the RESET to cancel the signaling.
3. Red LED TRIP (+ / -), in low insulation status, signals the polarity
under the trip threshold in a direct line, while both LEDs will be on in
an alternating line, functioning in automatic reset.
4. TEST button to test the instrument's functionality.
5. RESET button to cancel the trip signaling (manual reset).
6. Micro-switches to select the threshold for trip.

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MICRO-SWITCHES SETTING
The front micro-switches allow to set the threshold of trip between 10 and 60 kΩas it’s showed in the follow-
ing figure:
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WIRING CONNECTION
INSULATED NETWORK 24-48Vac/dc

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LEGEND
Auxiliary power supply
Terminals 1-3
The auxiliary power supply can be the same as the network to control.
Earth reference connection
Terminal 11
Connection to the earth or the protection conductor for measurement reference.
Relay output connections
Terminals 7-8-9
Changeover contact to indicate there is a fault, max 5A 250V on resistive load.
Remote TEST connection
Terminal 5
For the TEST function, it's possible to connect between this terminal and the ground (or protection conduc-
tor) a normally open contact to replicate the function of the TEST button externally to the device.
Automatic or remote RESET connection
Terminals 4-12
It’s possible to connect between these terminals a RESET button externally to the device, with a normally
closed contact to a remote reset function.
Make a short circuit between these terminals for a manual RESET with only the RESET button on the front of
the device. If the two terminals are not connected the device will operate with automatic RESET when the low
insulation condition stops.
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FUNCTIONALITY
In normal condition, with insulation value higher than the set threshold, the instrument has the green LED on.
Pressing the TEST button the TRIP LED of alarm signalling and the output relay will be activated.
Depending of the connection the RESET will be automatic when the TEST button is reIeased or using a remote
button or manual using the RESET button on the front panel.
If there is a low insulation in a direct line on + polarity (connection to terminal 1) will be activated the TRIP and
+ signalling, while the low insulation is present on the –polarity (connection to terminal 3) will be activated
the TRIP and –signalling.
In a alternate line all LED (TRIP, + and –) will be turned on.
The TRIP signalling will disappear, automatically or manually with RESET button, only when the insulation
come back higher than the set threshold, while the LED + and –work only in automatic RESET.

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TECHNICAL FEATURES
Auxiliary voltage supply
24-48V 50-60Hz/d.c. ± 20%
Maximum consumption
3 VA-3W
Measure current
max 0,5 mA
Internal impedance
50 kΩ
Threshold tripping
Settable 10 ÷ 60 kΩ(5 levels with micro-switches)
Tripping delay
About 0.2 seconds
Signalling and button
led ON, led TRIP, led +, led -
Output
Relay changeover contact NO-C-NC max 250V 5A
Working and storing temperature
-10 ÷ 60°C / -20 ÷ 70°C
Relative humidity
≤ 95 %
Insulation test
2,5 kV 60 sec. / 4 kV imp. 1,2/50μs
Mounting position
Any
Wiring type
Screw terminals / cross section cables 4 mm²
Protection degree
Front with cover: IP 40 –Enclosure: IP 20
Mounting according DIN 50022
Snap on DIN rail 35mm / 3 modules 17,5 mm
Weight
About 300 g
Standards
Safety EN 61010-1
Electromagnetic compatibility IEC-EN 61326-1
For application not described in this manual it’s better to see specific document or to contact the technical
service.
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NOTE
At reason of the evolution of standards and products, the company reserves to modify in every time the features of the product described
in this document, that it’s necessary to verify preventively.
The liability of the producer for damage caused by defect of the product ”can be reduced or deleted (…) when the damage is caused joint
by a defect of product or for blame of the damaged or a person of which the damaged is responsible” (Article 8, 85/374/CEE).
Snap on DIN rail 35mm
(DIN 50022)
3 modules 17,5 mm
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DIMENSIONS