Auxiliary Switch - Figure 18
shows the breaker mounted
auxiliary switch. This switch provides auxiliary contacts
for control of circuit breaker closing and tripping functions.
Contacts are available for use in relaying and external logic
circuits. This switch is driven by linkages connected to the
jack shaft. The auxiliary switch contains both “b” (Nor-
mally Closed) and “a” (Normally Open) contacts. When
the circuit breaker is open, the “b” switches are closed and
the “a” switches are open.
Figure 18.
Auxiliary Switch.
Limit Switches (Figure 19) - The motor cutoff switch (LS1)
is used to sense the position of the drive mechanism. This
switch de-energizes the charging motor when the Charged
position of the closing springs is reached. When the clos-
ing springs are discharged, this switch energizes the con-
trol circuit powering the spring charging motor.
Spring charged switch (LS2) operates simultaneously with
motor cutoff switch (LS1). The spring charged switch al-
lows the close solenoid to be energized only when the
springs are charged, and also is part of the anti-pump cir-
cuitry.
The trip latch check switch (LS3) operates when the trip
latch linkage is in the reset position.
Standard Schematic Diagrams
Note: Figure 20a shows a typical schematic for a circuit
breaker which is specifically intended for reclosing appli-
cation (standard for SDV breakers). Figure 20b shows a
breaker with capacitor tripping. These are typical - refer to
the specific drawing for your project.
Spring Charging Motor - Figure 15 shows the spring charg-
ing motor mounted at the top of the right side of the circuit
breaker operator housing. A mounting bracket holds the
motor firmly in place. A universal motor is used to permit
operation on either AC or DC control power.
The motor control circuits call for automatic charging of
the springs by the motor whenever control power is avail-
able and the springs are discharged. The springs auto-
matically recharge following a closing operation.
Electrical connections to the motor utilize a quick discon-
nect termination for easy inspection or removal.
Close Solenoid, Trip Solenoid and Anti-Pump Relay - Fig-
ure 17 shows the two solenoids controlling operation of
the circuit breaker by external electrical signals.
When the close solenoid is energized, it causes the two
closing springs to be released from their extended or
charged state. This forces the three insulating coupling
rods to move the movable vacuum interrupter contacts
toward the fixed contacts and close the circuit breaker.
The anti-pump relay (Figure 32) electrically isolates signals
to the close solenoid such that only one releasing action
by the close solenoid can occur during each application of
the close command. The circuit breaker must be tripped,
the springs recharged and the closing signal removed (in-
terrupted) before the close solenoid can be energized a
second time.
When the trip solenoid is energized, it allows rotation of
the jack shaft by the tripping spring. This rotation pushes
the insulating coupling rods attached to the movable con-
tacts of the three vacuum interrupters, and the circuit
breaker contacts are opened.
Electrical connections to the close solenoid and trip sole-
noid are made through quick disconnect terminations.
Figure 17.
Close (Left) and Trip (Right) Solenoids.
Interrupter/Operator Description
2093-98
Trip
Solenoid
Close
Solenoid
2092-98
17
