KEPCO BOP 5-20DL, Operator'S Manual

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3-22
BOP 5-20DL 081915
new SLAVE, front panel VOLTAGE PROGRAMMING INPUT. Place the MODE switch on the
BOP added to the series combination to VOLTAGE and the VOLTAGE CONTROL switch OFF.
1. Connect the BOP supplies as shown in Figure 3-24. Set the MODE switches and the VOLT-
AGE CONTROL switches as directed in the set-up diagram, Figure 3-24.
a. Load-wire size should be rated to at least the maximum load current and load-wire pairs
should be twisted or tied together to keep the inductance and EMI as low as possible. For
remote sensing, use #22 AWG twisted pair wires.
b. Use shielded cable for connecting the coupling resistor (R
T
). Connect shield to chassis-
ground. Either the positive or the negative output side of the system can be grounded.
c. The coupling resistor (R
T
) should be either a wirewound or a metal film component with a
low temperature coefficient. For BOP 5-20DL this value is 2.49K (either 1/4 or 1/2 Watt).
This value of R
T
will be able to drive the BOP Slave unit to its (±) maximum output voltage
as the BOP Master is controlled through its range.
d. Both BOP power supplies should be connected to the power line using a common circuit
breaker. Alternatively, the BOP Circuit Breaker Control Circuit, as described in PAR.
3.6.2, can be used to interconnect both BOP’s in such a way that if one of them should
fail, the other one is automatically shut down also.
2. Turn BOP‘s on and begin operation. The system as shown in Figure 3-24 operates in Volt-
age Mode, since the Master MODE switch is in VOLTAGE position. For operation in Current
Mode, transfer the Master MODE switch to CURRENT.
3.6.2 CIRCUIT BREAKER CONTROL CIRCUIT
The BOP is protected by the dual-coil circuit breaker/ON-OFF switch (CB101) as shown in Fig-
ure 3-25. The current sensing coil of CB101 is connected in series with the primary winding of
T201, thus detecting overcurrent reflected into the primary circuit and subsequently tripping the
circuit breaker. The voltage sensing coil of CB101 is connected in series with an SCR (CR4)
across the driver collector supply. If the SCR is triggered on, the voltage sensing coil is ener-
gized and trips the circuit breaker. The SCR (CR4) can be triggered in several ways:
• On a-c line power loss or interruption, Q1 will loose its turn-on bias first, due to the small
time-constant provided in its base circuit (not shown in the simplified block diagram). As
a result, Q2 is turned on, energizing the diode in the optical isolator (LC-1) and providing
a turn-on signal for the SCR (CR4).
• In the event of an excessive heat rise on the power stage assembly, the thermal switch
(S401) will close, energizing the diode in the optical isolator (LC-1) and providing thus
the turn-on signal for the SCR (CR4).
• An input signal applied across terminals 49 (+) and 47 (–) of the Rear Programming
Connector energizes the diode in the second optical isolator (LC-2) which, in turn, ener-
gizes the diode in the first optical isolator (LC-1), thus providing for SCR turn-on.
NOTE: Upon turn-off, an isolated output signal is available at Rear Programming Connector
terminals 26 (+) and 36 (–). This output signal can be used to turn off other equipment
when the BOP is turned off. As an example, applying it across terminals 49 and 47 of
the Rear Programming Connector of a second BOP allows the master of a parallel or
series configuration to turn off the slave when the master is turned off.