Figure 150: Tcs Scheme 3; Figure 151: Psl For Tcs Scheme 3 - GE P4A Technical Manual

Chapter 13 - Supervision
+ve
Output Relay
Opto-input
V01216

Figure 150: TCS Scheme 3

When the CB is closed, supervision current passes through the opto-input, resistor R2 and the trip coil. When the
CB is open, current flows through the opto-input, resistors R1 and R2 (in parallel), resistor R3 and the trip coil. The
supervision current is maintained through the trip path with the breaker in either state, therefore providing pre-
closing supervision.
5.3.1 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
48/54
110/250
220/250
Warning:
This Scheme is not compatible with Trip Circuit voltages of less than 48 V.
5.3.2 PSL FOR TCS SCHEME 3
Opto Input
*NC stands for Normally Closed.

Figure 151: PSL for TCS Scheme 3

296
Trip path
Opto Voltage Setting with R1
Fitted
24/27
48/54
110/125
0
dropoff
400
&
R3
52A
R2
52B
R1
Resistor R1 & R2 (ohms)
1.2k
2.7k
5.0k
50
pickup
0
Trip coil
Circuit Breaker
Resistor R3 (ohms)
600
1.2k
2.5k
0
Straight
0
Latching
P54xMED-TM-EN-1
P54A/B/C/E
-ve
*Output Relay
LED
User Alarm
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