Figure 5.4-2:Trip Circuit Supervision Scheme 2 (H6); Figure 5.4-3:Trip Circuit Supervision Scheme 3 (H7) - Siemens 7SR21 Manual

Scheme 2 (Intermediate)
+
R
Scheme 2 provides continuous Trip Circuit Supervision of trip coil with the circuit breaker Open or Closed. It does
not provide pre-closing supervision of the connections and links between the tripping contacts and the circuit
breaker and may not therefore be suitable for some circuits which include an isolating link.
Scheme 3 (Comprehensive)
Scheme 3 provides full Trip supervision with the circuit breaker Open or Closed.
©2010 Siemens Protection Devices Limited
BO
TRIP CCT n FAIL
BI
+ve -ve
BO 1 BO n
Remote
Alarm
Figure 5.4-2: Trip Circuit Supervision Scheme 2 (H6)
Figure 5.4-3: Trip Circuit Supervision Scheme 3 (H7)
7SR21 & 7SR22 Argus Applications Guide
52a
TRIP COIL
52a
Circuit
Breaker
52b
H6 Scheme Notes:
Resistor:
30V dc Nominal: R = 3K9
48V dc Nominal: R = 5K6
110V dc Nominal: R = 15K0
Chapter 7 Page 38 of 39
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