Bender ISOMETER isoHV525, Manual

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isoHV525_D00297_04_M_XXEN/05.2018
3. Function
3.1 isoHV525-M4-4
3.1.1 Features
 
Monitoring the insulation resistance R
F
for unearthed AC/DC systems
 
Automatic adaptation to the system leakage capacitance C
e
up to 150 μF
 
Two separate response values for Alarm 1 and Alarm 2
 
Alarms are signalled via alarm relays ("K1", "K2")
 
0. . . 10 V analogue output (galvanically separated)
3.1.2 Function description
The ISOMETER® measures the insulation resistance R
F
and the system leakage capaci-
tance C
e
between the system to be monitored (L1/+, L2/-) and earth (PE). If the value R
F
exceeds the set response values, this will be indicated by the relays "K1" and "K2".
If the insulation resistance
R
F
exceeds the release value (response value plus hysteresis),
the alarm relays switch back to their initial position.
The device function can be tested using the Test/Reset button.
3.1.2.1 Manual self test
The integrated self test function tests the function of the insulation monitoring device
and the connection to earth. A self test is started by pressing the external Test/Reset
button. Relay 1 ("K1") is switched during a manual self test. In the event of a fault, relay
2 ("K2") switches and the measuring function is interrupted.
Internal device errors can be caused by external disturbances or internal hardware er-
rors. After eliminating the fault, the alarm relays are automatically reset or are reset to
the initial position by pressing the Test/Reset
button. The self test can take a few minu-
tes.
The isoHV525 determines the system leakage capacitance via an
impedance measurement whose frequency is adjusted to the most
accurate insulation measurement. The measurement signal is influenced
by rectifiers or inverters, and can lead to phase errors which in turn can
lead to a distorted system leakage capacitance value.