supervision current is maintained through the trip path with the breaker in either state, therefore providing pre-
closing supervision.
4.3.1 RESISTOR VALUES
Resistors R1 and R2 are used to prevent false tripping, if the opto-input is accidentally shorted. However, unlike the
other two schemes. This scheme is dependent upon the position and value of these resistors. Removing them
would result in incomplete trip circuit monitoring. The table below shows the resistor values and voltage settings
required for satisfactory operation.
Trip Circuit Voltage
Opto Voltage Setting with R1
Fitted
Resistor R1 & R2 (ohms) Resistor R3 (ohms)
48/54 24/27 1.2k 600
110/250 48/54 2.7k 1.2k
220/250 110/125 5.0k 2.5k
Warning:
This Scheme is not compatible with Trip Circuit voltages of less than 48 V.
4.3.2 PSL FOR TCS SCHEME 3
Opto Input
V01217
&
*Output Relay
LED
User Alarm
pickup
0
50
0
400
dropoff
Straight
0
0
Latching
*NC stands for Normally Closed.
Figure 253: PSL for TCS Scheme 3
P446SV Chapter 17 - Supervision
P446SV-TM-EN-1 457
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