Insulation Monitoring; Insulation Fault Location - Bender ISOMETER isoPV1685RTU Manual

Function
Following each start-up, a new log file is generated. If the current file size exceeds 10 MByte
during operation, a new file is generated. The file name contains the time and date of the
creation time. The typical time that is needed until the maximum file size is reached is ap-
proximately 2 days. Hence, a µSD card with a memory space of 2 GByte can record data for
approx. 400 days.
When the maximum data limit is reached on your card, the oldest file in each case will be
overwritten. The history memory that is also copied to the µSD card contains all alarms in
csv. format.
3.3.3

Insulation monitoring

For insulation monitoring, a pulsating AC measuring voltage is superimposed onto the IT
system. The measuring pulse consists of positive and negative rectangular impulses of the
same amplitude. The period duration depends on the system leakage capacitances in each
case and the insulation resistances of the system to be monitored.
U
m
t
Pulse sequence of the measuring voltage for insulation fault monitoring
An insulation fault between the IT system and earth closes the measuring circuit. If the in-
sulation resistance between system and earth falls below the set response values R and
an1
(response value R can be set equal or higher than R ), the associated alarm relays
R
an2 an1 an2
K1 (11, 12, 14) or K2 (21, 22, 24) switch. Detected insulation faults are signalled to other bus
devices via the BMS bus. In addition, the alarm LEDs ALARM 1 or ALARM 2 light up.
3.3.4

Insulation fault location

For insulation fault location, a suitable locating current is superimposed onto the faulty IT
system with which insulation fault locators of the EDS... series can locate insulation faults.
The ISOMETER® features an internal locating current injector with I DC 50 mA.
L
I
L
2 s 4 s 2 s 4 s
t
Pulse sequence of the internal locating current injector for insulation fault location
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isoPV1685xxx_D00007_08_M_XXEN/03.2023