Westinghouse DBN-1016 Technical Manual page 15

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solenoid, in electrical operation. The relay
provides a means of closing the Circuit breaker
electrically from a remote point through a con-
trol switch.
The relay base (238) is molded from insu-
lating material. The contact assemblies, coil
assembly and other parts are attached to the
base. Frame (203) holds the coil in place and
serves as part of the magnetic circuit of coil
(206). The frame or yoke is secured to the
molded base by three screws (208). The coil
(206) is held in place by guide tube (207). The
relay is enclosed by molded cover (211) which
is secured
by
screw (239).
The moving core (204) is free to slide up
and down in the guide tube (207). In moving up
in response to the magnetic pull from the sta-
tionary core when the coil is energized, the
moving core pulls up latch (229) which is fas-
tened with pin· (227) to the mOving core. When
the coil (206) is energized, spring (225) bearing
against latch (229) holds the latch in such a
a poSition that it is hooked under latch pin (230),
causing moving contact arm assembly to rotate
counterclockwise around contact arm pin (232),
thereby compressing spring (235). The moving
contacts (236) are thus pulled against the sta-
tionary contacts (237) completing the circuit.
As the pin (230) is moved upward toggle
links (228) and (224) are raised. Toggle link
(228) pivots on pin (223) and toggle link (224)
is attached to the moving contact arm (234)
which pivots on pin (231). As the toggle links
move upward, the contact arm is rotated coun-
terclockwise and the relay contacts are closed.
When the relay contacts close, current starts
flowing through the coil (250) (Figure 1-2-5) of
the closing solenoid. The moving core (245)
of the solenoid moves up closing the circuit
breaker. Trip bracket (257) fastened to the
moving core of the solenoid forces the first
trip lever (225) of the relay trip assembly up;
increased spring tension rotates second trip
lever (253) which strikes the relay trip pin
(201) (Figure 1-2-4) forcing
it
upward. The
trip pin rotates the trip crank (220) which en-
gages the latch (229) and rotates it clockwise
against the torque exerted by torsion spring
(225). The rotation of latch (229) disengages
latch pin (230), the toggle links (224) and (228)
collapse and spring (235) rotates the mOving
contact arm (234) clockwise to snap the mOving
contacts (236) away from the stationary con-
tacts (237).
The main moving contacts (236) are fas-
tened to the contact arm (234) which is molded
CHAPTER l-GENERAL INFORMATION
from insulating material. Silver alloy contact
tips are brazed on the contact legs.
The main stationary contacts are made
from spring material and are
"u"
shaped. They
are secured to the base by screws (240). The
"U" shape arrangement causes a slight rolling
and wiping action on the spherically shaped con-
tact surfaces, as they meet, which helps to in-
sure a positive electrical connection.
With the Circuit breaker in the closed po-
sition, the trip pin (201) of the relay is held in
the trip position. Therefore, even though the
relay coil may be inadvertently energized when
the
circuit breaker is latched, the relay con-
tacts will not close and no current can flow
through the circuit breaker closing coil.
With the Circuit breaker in the closed po-
sition, if the control switch is held closed, the
moving core (204) will remain up with normal
or low control voltage. If breaker is tripped
open, relay latch (229) cannot engage latch pin
(230) until control switch is opened. Thus
breaker is "Anti-Pump" under low voltage con-
ditions and will not reclose until control switch
is opened and closed again.
Two
blowout coils (216) and (217) and two
arc chambers are provided so that the arc
drawn by the separating contacts may be ex-
tinguished and the Circuit opened in the least
possible time. The blowout coils are held in
place by two iron plates and secured by screws
(218). The blowout magnet coil is connected in
series with the contacts, which causes flux to
flow through the magnetic circuit and the air
gap of the blowout magnet assembly. The mag-
netic circuit is positioned so its air gap is
across the arc chamber and the arc. At the
time the contacts part and draw an arc, the arc
is deflected by the magnetic force down into
the arc chamber where it is extinguished due
to the stretching and cooling process. This
arrangement makes possible a small and effi-
Cient relay.
The relay is provided with a "seal-in" fea-
ture through the auxiliary contact (244) which
can be connected in parallel with the control
switch in the relay coil circuit.
If
this connec-
tion is made, once energized the relay will re-
main closed until breaker closing solenoid com-
pletes its stroke.
1-2-1-7 Closing Solonoid-(Soe Figure 1-2-5)
The closing solenoid is designed to operate
on direct current of rectifier (See Paragraph
1 - 2 - 1 - 1 6) and is used to close the circuit
1·9