21/07/2010
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MRAR 01/96 C
4. Design
4.1 Circuit Diagram
28
27
21
22
23
24
25
26
15
Supply
Reserve
External Reset
External Block
Sync. Check
CB Energy
Start Protection
Trip Protection
CB Status
Supply
POWER
SUPPLY
1
2
CASE
Supply
MRAR
54
55
53
External Reset
Blocking Input
L
N
L
CLOSE CB
33
31
29
32
30
34
48
52
50
45
43
41
44
42
46
40
38
36
37
35
39
+
7
9
10
Gnd
-
47
51
49
SELF SUPERVISION
AR BLOCKED
AR IN PROGRESS
HIGH SET BLOCK
RS485
Note:
Terminals 1 and 2, and inputs 21 - 28 and 15 are not to be tested by the application of a high
voltage power frequency input ("flash tested"), as this will cause damage to the unit.
Explanation of the Circuit Diagram
4.1.1 Information Inputs
Using the information inputs the
MRAR
relay decides whether and when auto-reclosing will take place.
Circuit Breaker Status (28)
With input terminal 28, the position of the circuit breaker can be supervised. When the circuit breaker is
closed, mains supply uninterrupted, the auxiliary voltage is connected to terminal 28.
Protection Energised (21)
When protection is energised, e.g. from over current time protection, a fault timer is started. The
MRAR
relay changes from a "Ready" status to a "Starting" status. (see also para 4.3.4).
