Bender VMD460-NA - Page 75

Maintenance, troubleshooting, messages
75
VMD460-NA_D00001_05_M_XXEN/01.2020
At least one undervoltage limit value must have been set because a measured value of
0 V is simulated at L
1-N
for the duration of the self test. The test continues until the dis-
connection time for "Undervoltage" t
(OFF)
has elapsed but no more than two minutes.
• During the self test, the time is measured that passes until the disconnection command
is given by the VMD460-NA (t
(OFF) DEVICE
).
• When contact monitoring is activated for K1, the time until the interface switch K1 has
actually disconnected is additionally measured (t
(OFF) TOT
).
The times measured will be indicated on the display as an alarm for 10 seconds. In ad-
dition, the times can be viewed in the Menu: 1. Alarm/measured values under channel 16
(t
(OFF) TOT
) and channel 17 (t
(OFF) DEVICE
).
Fig. 7.1: Comments on the timing diagram:
• Times (*) are measured during the self test
– t
(OFF) DEVICE
is the disconnection time of the VMD460-NA;
– t
(OFF) TOT
will only be measured when contact monitoring is activated by K1
and has been connected..
•t
interface switch 1
= t
(OFF) TOT
- t
(OFF) DEVICE
• All standards (with the exception of CEI 0-21): When disconnecting the generating plant
the redundancy (K2) switches to the first interface switch K1 with a delay of 50 ms. After
reconnection, K2 closes first and K1 with a delay of 50 ms. In this way, the redundant
interface switch is protected, as it always switches free of load.
• As soon as the system voltage exceeds the switching threshold again, the start-up delay
t
(ON)
begins.
t
off
t
off
U<
t
on
Relais K1
* t
off GERAET
* t
off(GES)
t
Kuppelschalter 1
Rückmelde-
kontakt D1
50 ms
Relais K2
Rückmelde-
kontakt D2
Redundanz (Kuppelschalter 2)
t
Kuppelschalter 2
Diagramm Schaltzeiten: Relais und Rückmeldekontakte
Netzspannung
t
Kuppelschalter 1
t
Kuppelschalter 2
50 ms