Table of Contents
Advertisement
Supervision Functions
6.5 74TC Trip-Circuit Supervision
Parameter: Delay
•
Default setting: 0.4 s
Time delayed operation prevents failure being incorrectly indicated during circuit‑breaker operation. This
delay should be greater than the operating time of the circuit‑breaker.
Settings Example
Binary inputs may be used to monitor the integrity of the CB trip and close circuit wiring. A small current flows
through the BI and the circuit. This current operates the BI confirming the integrity of the auxiliary supply, CB
coil, auxiliary switch, C.B. secondary isolating contacts and associated wiring. If monitoring current flow
ceases, the BI drops off and if it is user programmed to operate 1 of the output relays, this can provide a
remote alarm. In addition, an LED on the relay can be programmed to operate. A user text label can be used to
define the operated LED e.g. Trip CCT Fail.
The relevant binary input is mapped to 74TCS-n or 74CCS in the Input Config > Input Matrix menu.
To avoid giving spurious alarm messages while the circuit‑breaker is operating the input is given a 0.4 s drop-
off delay in the Input Config > Binary Input Config menu.
To provide an alarm output a normally open binary output is mapped to 74TCS-n or 74CCS-n.
The following circuits are derived from UK ENA S15 standard schemes H5, H6 and H7.
For compliance with this standard:
•
Where more than 1 device is used to trip the CB then connections should be looped between the tripping
contacts. To ensure that all wiring is monitored the binary input must be at the end of the looped wiring.
•
Resistors must be continuously rated and where possible should be of wire-wound construction.
Scheme 1 (Basic)
[dw_7SR5_function74TCSettingExample1, 1, en_US]
Figure 6-12
Scheme 1 provides full trip supervision with the circuit‑breaker Open or Closed. Where a Hand Reset Trip
Contact is used, measures must be taken to inhibit alarm indications after a CB trip.
390
Trip‑Circuit Supervision Scheme 1 (H5)
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
Advertisement
Table of Contents
