Bender LINETRAXX VMD461, Руководство пользователя

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Function
17 VMD461_D00314_01_M_XXEN/10.2018
3.3 Functional description
Once the supply voltage is applied, the start-up delay t
start-up
begins. Meas-
ured voltage and frequency values changing during this time do not influence
the switching state of the alarm relays K1 and K2.
The devices feature three separately adjustable limit values for overvoltage/
undervoltage as well as overfrequency/underfrequency which are respective-
ly linked to their own response delay
t
off
.
If the measured quantity exceeds or falls below the set response value and the
related response delay
t
off
has elapsed, the relay assigned to the response val-
ue switches and the corresponding LED lights.
Fault memory
When the fault memory is disabled, the device automatically attempts to
switch on:
If the measured quantity falls below or exceeds the release value after the
alarm relays have switched, the set switch-on delay
t
on
starts.
When the fault memory is enabled, the fault must be manually reset on the
device.
df/dt
A passive method for islanding detection (three-phase voltage and frequency
monitoring).
Nominal voltage and overvoltage limit values U>, U>>
and U>>> (ANSI code 59)
By means of the nominal voltage and the overvoltage pa-
rameters, limit values above the maximum voltages of the
measuring circuit (compare "Chapter 8. Technical data
VMD461) can be set.
The user must ensure that the overvoltage limit values
do not exceed the maximum voltages.
CAUTION