EN
Description and operation mode
The relays for permanent control of insulation SRI3/I2 monitors continuously the status of networks with neutral to ground (IT systems). The
instruments can detect insulation faults due to the resistive components, even in the presence of continuous parasitic tensions. The devices are
able to give two different levels of signaling.
The insulation resistance measurement is performed by applying an alternating voltage of less than 24Vp-p (conforms to IEC61557-8) in a self-
adaptive variable frequency.
NOTE
:In the presence of strong interference or discontinuity in the system, on display of device may flash the value of
the insulation resistance or it can be temporary replaced with the written "EVAL". This means, that this value is subject to verification. At final check,
the value of resistance will return as fixed value.During this procedure, the dispersion resistance will not be measured.
Installation Rerquirement and Safety Precaution
All installation and maintenance operations must be performed by qualified personnel, in the absence of voltage and total electrical safety system,
in compliance with the regulations. See the picture on the first page FIG3 and FIG4 for a right installation.
- Before powering the equipment, check that you have correctly performed all the necessary connections.
- The conductors section must be between 1.5 and 2.5 mm2, except those relating to the serial interface.
-
In the case you use the IMD with the expansion SRI3/EXT2, it must mandatory be placed to the left of IMD (insulation monitor device).
TECHNICAL FEATURES
Nominal Voltage
Un
AC/DC 0 - 500V
DC 0 - 700V
Aux Power Supply
Us
Consumed power
115/230Vac(50/60Hz) (for SRI3/I2)
24/60Vdc (for SRI3/I2CC)
<10VA
Distribution System- Type of IMD
IT - AC/DC IMD
Overvoltage category
Pollution degree
CAT II
2
Reference Standard
IEC 61557-8
IEC 61326-2-4
Protection degree
IP40 (Frontal)
IP20 (Terminal)
Working temperature
-10 ÷ 50°C
Storage temperature
-20 ÷ 80°C
Maximum altitude
2000m
Max terminal section
2,5mm²
Insulation Measure
Ran
(Response value)
5KΩ ÷ 2MΩ
Rf
measurable resistance
1KΩ ÷ 10MΩ
Tan in ac
(Response time)
Tan in dc or in dc+ac with Ufg >0
≤10sec (with Cdisp=1μF)
100sec (with Cdisp=1μF)
Relative uncertainty
2kΩ (1kΩ
20kΩ)
10% (20kΩ
2MΩ)
Max external voltage in DC
Ufg
<575Vdc
Max dispersion capacity
≤100μF
Ri
–
Zi
(Internal resistance- Impedance
@ 50 Hz)
≥200KΩ
Measuring voltage
Um
Measuring current
Im
≤24V
≤250uA
Internal temperature and voltage measure
Accuracy of temperature measured
3°C
Measure Range
-10 ÷ 110°C
Threshold values selectable
50 ÷ 90°C
Alarm Response time
~ 5sec
Minimum/ Maximum voltage range
0 ÷ 700V
Accuracy of voltage
measure
±5%
Interfaces
Number of output contacts
3 NO-C-NC
Output breaking capacity
250Vac- 3A PF=1
Serial interface
RS485 Modbus RTU
Galvanic insulation
<1kV @50Hz
Terminating resistance
~ 120Ω
When the instrument is in the normal state of measurement and monitoring, the
following parameters are constantly displayed on the display (green color):
- Insulation Resistance (Ran)
- Line voltage (only if the alarm thresholds are different from zero)
- Symbol of the voltage type
- Internal temperature in °C (only if the thermal alarm threshold is different from zero)
- Graphic representation of the insulation resistance with an histogram which represent
insulation resistance when is between the 2 set thresholds (alarm and fault)
- Contacts status of device
The keys funcions are:
1
:TEST- push to perform the test
2
: SET- push for at least 3 secs to enter/exit in/from SETUP
3
: push for contrast adjustment
4
: i- push for product information
Normal activity of insulation control (Green display)
