23
The schematic shown in Figure 14: Typical
circuit breaker schematic on page 24 is
intended to aid in understanding the
mechanism operation discussed in this
instruction manual. Refer to the schematic
diagram furnished with your circuit breaker
for specific information.
Also, refer to Figure 12: Operator sequential
flow diagram on page 19 and Figure 13:
Magnetic-actuator controller flow diagram
on pages 20-21.
Electrical operations are performed through
the magnetic-actuator controller using the
stored energy in the capacitor boards.
Local electrical operation is initiated using
the black Close (53.0) or Open (54.0)
pushbuttons (refer to Figure 3: Operator
panel controls on page 10), designated as
S2 and S3 in Figure 14: Typical circuit
breaker schematic on page 24. External
commands (for example, from protective
relays or remote circuits) for closing or
opening can be connected through
terminals A2/C3 and A4/D3 as shown.
Electronic controller binary inputs/
outputs
The status output contacts (for controller
energy status and circuit breaker position)
available from the electronic controller are
shown on the schematic diagrams (Figures
14 on page 24 and 15 on page 25). These
status output contacts have ratings as
follows:
N.O. contacts (terminals 1-6, 2-6, 4-6 and
5-6 on -ST2):
Switching capability: 375 VA ac/
90 W dc (resistive)
Current rating: 3 A
Voltage rating: up to 240 Vac or
250 Vdc.
N.C. contacts (terminals 3-6 on -ST2):
Switching capability: 5 A@24 Vdc;
0.4 A@48 Vdc; 0.2 A@125 Vdc;
0.15 A@250 Vdc (all resistive)
Current rating: 3 A
Voltage rating up to 240 Vac or
250 Vdc.
The alarm contact (ST2-3/ST2-6 in Figure
15: Controller schematic on page 25) opens
when an alarm condition begins.
Approximately five seconds after all error
conditions cease, the red LED is turned off
and the alarm contact opens. If the control
voltage fails or is removed, the alarm
contact closes and remains closed until
control power is restored.
The binary inputs (for electrical closing or
opening commands from pushbuttons,
protective relays, etc.) have a threshold of
response as follows:
For high-range model, input voltage to
the binary inputs must be at least 53 Vac
or 69 Vdc for operation
For low-range model, input voltage must
be at least 17 Vac or 17 Vdc for
operation.
For increased security of close and open
operations, the control signal to initiate a
close or open action must exceed the
threshold response voltage above for at
least 10 ms (for dc power) or 20 ms (for ac
power) to be considered a valid command.
Commands which do not persist for at least
10 ms (for dc power) or 20 ms (for ac
power) are ignored by the microprocessor.
To allow for microprocessor processes and
circuit breaker function, a minimum signal
duration of 100 ms is recommended.
If controller power fails, capacitors retain
sufficient charge to open the circuit breaker
within 300 seconds, with minimum
command duration of 100 ms (mandatory).
Auxiliary switch (52a/b)
Figure 8: Magnetic-actuator operating
mechanism on page 15 shows the circuit
breaker mounted auxiliary switch (68.0).
This switch provides auxiliary contacts for
use in control and protection circuits.
Contacts are available for use in relaying
and external logic circuits. This switch is
driven by linkage (68.1) connected to the
jack shaft (63.0). The auxiliary switch
contains both “b” (normally closed) and “a”
(normally open) contacts. When the circuit
breaker is open, the “b” contacts are closed
and the “a” contacts are open.
