TECHNICAL FIELD
[0001] This invention relates to an auxiliary device for a circuit breaker, targeting circuit
breakers for wiring applied to low-voltage power distribution equipment and earth
leakage circuit breakers, and more specifically relates to the configuration of an
undervoltage tripping device and an external operating handle device which are mounted
on a circuit breaker and used as auxiliary devices of the circuit breaker.
BACKGROUND ART
[0002] As is well known, various auxiliary devices are prepared as options for the circuit
breaker of the title; one such device is an undervoltage tripping device.
[0003] This undervoltage tripping device trips the circuit breaker when the voltage of a
circuit for protection (voltage of the main circuit or control circuit) falls below
a voltage stipulated in advance (for example, in the range 35 to 85% of a rated voltage),
thereby shutting off the main circuit. As one example, internal type undervoltage
tripping devices are known which are inserted into and set inside the case of a circuit
breaker for use (see for example Patent Reference 1).
[0004] Such an internal type undervoltage tripping device is provided with a tripping mechanism
that is mounted on a cassette case within the case of the circuit breaker, and is
constituted by an assembly of an electromagnet, an actuator joined to the armature
of the electromagnet so as to be opposed to a tripping crossbar of the circuit breaker,
an armature release spring, and a reset lever linked to the armature.
[0005] Operation and functions of such an undervoltage tripping device are described in
detail in Patent Reference 1; the coil of the electromagnet is excited by a current
passed by a control circuit with the main circuit of the circuit breaker as its power
supply, and attracts the armature of the electromagnet in opposition to the release
spring during stationary operation, so as to hold the actuator in the retracted position.
On the other hand, when the voltage of the main circuit falls below a stipulated range,
the attractive force of the electromagnet is reduced, and restraint of the actuator
is removed. As a result, the actuator receives the biasing force of the release spring,
strikes the trip crossbar, and causes tripping operation of the circuit breaker.
[0006] After tripping operation, when the handle of the circuit breaker is operated from
the OFF to the ON position, the reset lever of the undervoltage tripping device linked
thereto returns the actuator to the retracted position in opposition to the release
spring. In this state, if the main circuit voltage has returned to the stipulated
range, the electromagnet attracts and holds the armature, and the actuator is held
in the retracted position, so that reclosing of the circuit breaker is established.
[0007] As an undervoltage tripping device of a circuit breaker, an undervoltage tripping
device with an early closing contact, which combines the above-described tripping
mechanism with an early closing contact switch, in which this early closing contact
switch is connected to the power supply circuit of the electromagnet coil, is also
known (see for example Patent Reference 2).
[0008] This undervoltage tripping device with an early closing contact performs circuit
breaker closing safely and accurately, and so in the above-described configuration
which combines an early closing contact switch mechanism with a tripping mechanism
including an electromagnet, in a state of use in which this device is mounted on a
circuit breaker, the early closing contact switch mechanism is linked to a driving
lever (cam type lever) or similar provided on the handle of the circuit breaker.
[0009] When, in the process of handle operation for reclosing after a tripping operation
of the circuit breaker, the handle of the circuit breaker, which is halted in the
TRIP position, is returned once to the OFF position and then moved toward the ON position,
the early closing contact is closed before closing of the main circuit contact of
the circuit breaker, and the electromagnetic coil is excited by a current. At this
time, if the voltage of the main circuit has returned to a voltage in the stipulated
range, the armature of the electromagnet of the tripping mechanism is attracted and
held, and the actuator is held in the retracted position, so that when the handle
is moved to the ON position, reclosing of the circuit breaker is established. On the
other hand, if the main circuit voltage has not returned to a stipulated voltage,
the electromagnet armature is not attracted, so that even when the handle is moved
to the ON position, the circuit breaker is not reset, and returns to the tripped state.
[0010] An undervoltage tripping device with an early closing contact is large in size compared
with the internal type undervoltage tripping device disclosed in Patent Reference
1, and without further modification, incorporation within the case of a circuit breaker
would be difficult; hence normally a unit case is external mounted on a side face
of the circuit breaker case, as in Patent Reference 2, and is linked via a driving
lever onto a driving handle, which is a rotary handle of the circuit breaker onto
which the early closing contact switch mechanism is mounted.
[0011] On the other hand, the above-described circuit breakers (circuit breakers for wiring,
earth leakage circuit breakers) are generally installed on and used in wiring boards,
distribution boards, and similar, and as auxiliary devices, externally operated handle
devices which perform operations to open and close the circuit breaker from the front
of the panel door are used. As one such example, a design is known in which a rocker
handle of the circuit breaker is driven to the ON, OFF and RESET positions by operation
of the rotary handle mounted on an external operating handle device (see for example
Patent Reference 3).
[0012] Next, the structure of a conventional example of an external operating handle device
is explained using Fig. 8. In Figs. 8(a) to 8(c), 1 is a circuit breaker (wiring circuit
breaker), and 2 is an external operating handle device, mounted on the case of the
circuit breaker as an auxiliary device of the circuit breaker 1. Here, the circuit
breaker 1 is configured comprising, installed in a case 1a, an open/close mechanism
1b, movable contact point 1c, open/close mechanism 1d comprising a reversal operation
type toggling mechanism, rocker handle 1e disposed on the top of the case 1a and linked
to the open/close mechanism 1d, and overcurrent tripping device 1f, and similar. 5a
is a nameplate displaying the positions ON, OFF, TRIP, RESET of the handle 4.
[0013] The open/close operation of the above circuit breaker 1 is well known; when the rocker
handle 1e is switched by moving from the ON position as shown to the right and downward
to the OFF position, in the midst of this stroke the open/close mechanism 1d performs
a reversal operation, receiving the biasing force of the open/close spring of the
open/close mechanism 1d to open the movable contact point 1c. Further, when a main
circuit overcurrent is detected and the overcurrent tripping device 1f operates, the
open/close mechanism 1d performs a release operation, the movable contact point 1c
is opened, and the main circuit current is cut off. Through this tripping operation,
the rocker handle 1e moves to a position intermediate between the ON position and
the OFF position, and displays the trip operation state.
[0014] On the other hand, the external operating handle device 2 comprises, mounted on a
base 3 fixed in place by fastening with screws to the top of the case 1a of the circuit
breaker 1, a rotary handle 4, handle cover 5, sliding base 6 and other driving components;
a turning base 4b linked to a support shaft 4a of the handle 4 comprises a crank pin
4c. The sliding base 6 is slidably guided and supported in a direction parallel to
the rocker handle 1e of the circuit breaker 1, and a long hole 6a directed perpendicular
to the sliding direction is opened in the plate face thereof; the crank pin 4c is
mated with this long hole 6a and linked with the rotary handle 4. Further, in a state
in which the external operating handle device 2 is mounted on the circuit breaker
1, the sliding base 6 comprises a pusher 6b which opposes, from the ON side, the knob
of the rocker handle 1e protruding from the case 1a of the circuit breaker 1, and
a biasing spring 6c which presses the pusher 6b from behind toward the knob of the
handle 1e.
[0015] In the above configuration, when the rotary handle 4 is rotated in manual operation
from the ON position to the OFF position, the sliding base 6 slides rightward via
the crank pin 4c, and the rocker handle 1e of the circuit breaker 1 is driven toward
the OFF position via the pusher 6b. Here, when the handle 1e is displaced to substantially
the intermediate position of the movement stroke, the toggling mechanism of the open/close
mechanism 1d provided in the circuit breaker 1 performs reversal operation. By this
means, the movable contact point 1 c recedes from the fixed contact point 1 b and
moves to the open position, and the circuit breaker 1 is turned OFF.
[0016] Further, when the circuit breaker 1 detects and overcurrent and performs tripping
operation, the handle 4 of the external operating handle device 2 linked to the rocker
handle 1e moves to the TRIP position intermediate between the ON position and the
OFF position, and halts. And, in order to reclose the circuit breaker 1 from this
state, first the rotary handle 4 is turned to the RESET position. By this means, the
tripping mechanism linked to the open/close mechanism 1d of the circuit breaker 1
is reset, and then when the rotary handle 4 reversed and turned to the ON position,
the rocker handle 1 e of the circuit breaker 1 moves to the OFF position, and the
movable contact point 1 c makes contact with the fixed contact point 1 b, establishing
reclosing of the circuit breaker 1.
[0018] Patent Reference 4 discloses an under-voltage tripping device installed on a main
body of a circuit breaker including an electromagnetic under-voltage tripping mechanism,
an early-operation auxiliary switch for switching a conductive path of an electromagnet
of the electromagnetic under-voltage tripping mechanism in connection with a handle
mechanism of the circuit breaker, and a unit case having two opposite ends and external
connection terminals at the two opposite ends.
[0019] Patent Reference 5 discloses a circuit breaker and an auxiliary device including
an undervoltage tripping mechanism and an early closing contact mechanism. Both mechanism
are coupled to each other.
[0020] Patent Reference 6 teaches an auxiliary device for a circuit breaker, comprising
an electrical protection unit that cooperates, by means of a mechanism, with an opening
slider biased by a return spring. In case of a voltage drop, the opening slider is
released acting on a safety release lever of an enclosed circuit breaker.
[0021] However, the above-described conventional undervoltage tripping devices and external
operating handle devices prepared by manufacturers as auxiliary devices for circuit
breakers have the following problems in accommodating optional specifications specified
by users.
[0022] That is, various auxiliary devices prepared by manufacturers as options for the above-described
circuit breakers are adopted to accommodate the specifications of users. In such cases,
optional undervoltage tripping device products include, as described above, normal
internal type undervoltage tripping devices not provided with an early closing contact
(see Patent Reference 1), and undervoltage tripping devices with an early closing
contact (see Patent Reference 2); these specifications further differ according to
the type, rated voltage, and other parameters of the circuit breaker. In addition,
there are also cases in which a circuit breaker is combined for use with an external
operating handle device, and in these and other ways, auxiliary device types vary
according to the environment of use of the circuit breaker, user specifications, and
similar.
[0023] Hence circuit breaker manufacturers must prepare various types of undervoltage tripping
devices with different specifications and designs in anticipation of options specified
by users, and costs are entailed in stocking and managing such optional products.
[0024] However, when adopting the above-described undervoltage tripping device with an early
closing contact (see Patent Reference 2) as an auxiliary device for a circuit breaker,
it is necessary to equip the circuit breaker in advance with a dedicated rotary handle
provided with a driving lever which is linked to the early closing contact switch
mechanism.
[0025] However, in an ordinary circuit breaker (see Fig. 8) a rocker handle is not provided
as standard, and when adopting an undervoltage tripping device with an early closing
contact, various circuit breakers provided with dedicated rotary handles must be used.
If the above-described dedicated rotary handle is provided as standard in a circuit
breaker in advance, in anticipation of accommodating an undervoltage tripping device
with an early closing contact, there is the problem that in cases where an undervoltage
tripping device with an early closing contact is not used, specifications are excessive,
and the cost of the circuit breaker product is increased.
DISCLOSURE OF THE INVENTION
[0026] This invention was devised in light of the above problems, and has as an object the
provision of an auxiliary device for a circuit breaker wherein, with respect to an
undervoltage tripping device applied to a circuit breaker, optional products related
to the undervoltage tripping device can be divided into a plurality of units and configured
in advance, and units selected according to option specifications specified by a user
can be combined and used with a circuit breaker, to enable accommodation of specifications
with various options specified by simple means.
[0027] In order to attain the above object, an auxiliary device of a circuit breaker according
to one embodiment of the invention is an auxiliary device of a circuit breaker which
has, as the auxiliary device, an external operating handle device and an undervoltage
tripping device, wherein the undervoltage tripping device is divided into two modules,
which are a tripping unit comprising a tripping mechanism and an early closing contact
unit comprising an early closing contact; the tripping unit is internally provided
in a case of the circuit breaker, the early closing contact unit is externally provided
on the external operating handle device such that the early closing contact is linked
to an internal mechanism of the external operating handle device, and the early closing
contact is closed midway during ON operation of the external operating handle device
and before a main circuit contact of the circuit breaker closes.
[0028] Further, the auxiliary device of a circuit breaker according to one embodiment of
the invention is the external operating handle device, comprising a base mounted on
the case of the circuit breaker; a rotary type handle; a sliding base which converts
rotation of the handle into linear motion and drives a rocker type handle of the circuit
breaker in ON and OFF directions; a pusher, installed on the sliding base and opposed
to the rocker type handle from the ON operation direction; and a spring which biases
the pusher from the rear, the external operating handle device being configured with
a backlash stroke set between the sliding base and the pusher, and the movement of
the sliding base corresponding to the backlash stroke is captured, and the early closing
contact of the early closing contact unit is caused to perform open/close operation,
in the process of turning on the circuit breaker.
[0029] Further, in the auxiliary device of a circuit breaker according to one embodiment
of the invention, the early closing contact unit comprises an assembly of a limit
switch provided with the early closing contact, and a frame with a terminal which
holds the limit switch; the frame is detachably mounted on a base of the external
operating handle device, and an operation end of the limit switch is linked to the
sliding base of the external operating handle device at this mounted position.
[0030] By means of an auxiliary device of a circuit breaker of this invention, by configuring
an undervoltage tripping device as described above as an auxiliary device of a circuit
breaker, the minimum number of types of optional products can be selected appropriately
and applied to the circuit breaker, so that various specified option specifications
can be accommodated by simple means.
[0031] That is, when a normal undervoltage tripping device not having an early closing contact
function is applied as an auxiliary device of a circuit breaker, immediate accommodation
is possible by providing the tripping unit internally in the case of the circuit breaker.
Further, in this case an external operating handle device can be mounted on the circuit
breaker as necessary.
[0032] On the other hand, as an undervoltage tripping device, when the option specifications
are changed to include an early closing contact function, the above-described existing
tripping unit is internally provided without modification in the case of the circuit
breaker, and an early closing contact unit can be added as an optional product, externally
mounted on the external operating handle device mounted on the circuit breaker, to
accommodate specifications by simple means. Hence circuit breaker manufacturers may
prepare a smaller number of optional products than in the prior art, and the costs
entailed in stocking and managing such optional products can be greatly reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033]
Fig. 1 is an exploded perspective view of an example of this invention, in which the
auxiliary devices of an external operating handle device and an undervoltage tripping
device are mounted on a circuit breaker;
Fig. 2 shows the configuration of an undervoltage tripping device with an early closing
contact applied to the circuit breaker of Fig. 1, in which Figs. 2(a) and 2(b) are
perspective views of the tripping unit and the early closing contact unit respectively;
Fig. 3 shows the assembled structure of the external operating handle device in Fig.
1, in which Fig. 3(a) is an exploded perspective view of the entire device, and Fig.
3(b) is an exploded perspective view of the sliding base in Fig. 3(a);
Fig. 4 shows states of operation of the external operating handle device shown in
Fig. 3, wherein Figs. 4(a) and 4(b) respectively show the states of rotating the handle
to the ON and OFF positions;
Fig. 5 is an external perspective view of the state of use when the early closing
contact unit of Fig. 2 is externally mounted onto the external operating handle device
of Fig. 3, which is mounted on the circuit breaker;
Fig. 6 is an external perspective view of a state of use with the early closing contact
unit removed in Fig. 5;
Fig. 7 explains handle operation in a state of use of the early closing contact unit
of Fig. 5, in which Figs. 7(a) to 7(d) show transitions in the handle position when
rotating the handle of the external operating handle device from the OFF position
to the ON position, and Figs. 7(e) to 7(h) show transitions in the operation of the
sliding base, pusher, circuit breaker rocker handle and early closing contact unit
corresponding to Figs. 7(a) to 7(d) respectively; and
Fig. 8 shows the structure of the state of use with a conventional external operating
handle device mounted on a circuit breaker, in which Fig. 8(a) is a side cross-sectional
view, Fig. 8(b) is a plane view, and Fig. 8(c) is a perspective view showing the internal
mechanism of the external operating handle device.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] Below, embodiments of the invention are explained based on Fig. 1 to Fig. 7. In the
embodiments, members corresponding to members in Fig. 8 are assigned the same symbols,
and explanations are omitted.
[0035] First, Fig. 1 shows an example of this invention, which is an external operating
handle device and undervoltage tripping device mounted as auxiliary devices on a circuit
breaker. In the figure, 1 is the circuit breaker comprising a rocker handle 1e on
the top of a case 1a, 2 is the external operating handle device, 7 is a tripping unit
of the undervoltage tripping device, internally provided in the case 1a of the circuit
breaker 1, and 8 is an early closing contact unit of the undervoltage tripping device,
detachably mounted externally on the rear-face side of the base 3 of the external
operating handle device 2, disposed between [the base 3 and] the circuit breaker 1.
[0036] Here, the tripping unit 7 is configured with a tripping mechanism, including an electromagnet,
mounted on a cassette-type unit case as shown in Fig. 2(a), similarly to that of Patent
Reference 1 described above. 7a is an actuator opposed to a trip crossbar of the circuit
breaker, protruding from the unit case, and 7b is a reset lever. On the other hand,
as shown in Fig. 2(b), the early closing contact unit 8 comprises an assembly of a
limit switch 8a provided with an early closing contact, and a mounting frame 8b which
holds the limit switch 8a; the mounting frame 8b comprises an external connection
terminal 8c, terminal screws 8d, and a pair of support legs (snap fits) 8e protruding
upward from both ends of the mounting frame 8b.
[0037] Further, the external operating handle device 2 has substantially the same configuration
as the conventional external operating handle device shown in Fig. 8; the detailed
structure thereof is shown in Fig. 3. That is, the sliding base 6 mounted on the base
3 of the external operating handle device, guided in a straight line and supported,
has a pin 6d erected on the upper-face side thereof which mates with a groove 4b-1
in the turning base 4b, and is linked to the rotary handle 4 via a support shaft 4a.
Further, a window hole 6e, with the shape of a small square placed on a large lateral
rectangle, is cut out and opened in the plate face of the sliding base 6, and as explained
below, a pusher 6b, opposed from the ON side by the rocker handle 1e (see Fig. 1)
of the circuit breaker 1, set with a backlash stroke with the sliding base 6, and
a weak spring (coil spring) 6c which biases the pusher 6b from behind, are set in
this window hole 6e. Further, a cam groove 6f which functions as a dog opening and
closing the limit switch 8a (see Fig. 2(b)) of the above-described early closing contact
unit 8 is formed in a side face of the sliding base 6 along the direction of movement.
[0038] Figs. 4(a) and 4(b) show the assembled state of the external operating handle device
2; when the rotary handle 4 is rotated manually to the ON and OFF positions, the sliding
base 6, linked to the handle 4, slides and moves in a straight-line direction, and
as shown in Fig. 8, drives the rocker handle 1e of the circuit breaker 1 to the ON
and OFF positions.
[0039] Further, Fig. 5 shows the state of use in which the early closing contact unit 8
of the undervoltage tripping device is additionally mounted on the external operating
handle device 2, mounted on the circuit breaker 1 (although not shown, the tripping
unit 7 of the above-described undervoltage tripping device is internally set in the
case of the circuit breaker). Here, the early closing contact unit 8 is snap-fit and
detachably joined by pressing, from the rear-face side, the support legs 8e provided
in the frame 8b into engaging holes 3e (see Fig. 1) opened in the base 3 of the external
operating handle device 2. Further, in this assembled state, the terminals 8c of the
early closing contact unit 8 are connected to the exciting circuit of the electromagnet
coil incorporated in the tripping unit 7. On the other hand, Fig. 6 shows the state
of use in which an early closing contact unit 8 is not used, and the tripping unit
7 is internally set in the case of the circuit breaker 1.
[0040] That is, by employing a configuration in which the undervoltage tripping device is
divided into two optional parts, which are the tripping unit 7 and the early closing
contact unit 8, cases where an undervoltage tripping device without an early closing
contact function is applied as an option can immediately be accommodated by inserting,
setting and using the tripping unit 7 in the case 1a of the circuit breaker 1, as
in Fig. 6.
[0041] Further, in cases where this undervoltage tripping device is to be provided with
an early closing contact function, by adding the early closing contact unit 8 and
mounting on the external operating handle device 2 as in Fig. 5, optional specifications
for an undervoltage tripping device with an early closing contact can be accommodated
by simple means.
[0042] Next, in a state of use in which the early closing contact unit 8 is mounted on the
external operating handle device 2, Fig. 7 is used to explain transitions in operation
of the early closing contact corresponding to handle operation.
[0043] First, Figs. 7(a) and 7(e) show a state in which the rotary handle 4 of the external
operating handle device 2 is halted in the OFF position. In this state, the sliding
base 6 is halted on the left end of the movement stroke by the biasing force of a
return spring 9 (tension coil spring), and in this position a backlash stroke L1 is
held between the rear end of the pusher 6b, being biased by the spring 6c, and the
rear end of the window hole 6e opened in the sliding base 6. Further, in this position
the limit switch 8a of the early closing contact unit 8 disposed on a side face of
the sliding base 6 is opposed to the cam groove 6f of the sliding base 6, and the
early closing contact is OFF.
[0044] When, from this state, rotation of the rotary handle 4 toward the ON position is
begun (see Fig. 7(b)), the sliding base 6, driven by this rotation, begins to move
rightward. In this case, in the stroke range immediately after the start of motion
corresponding to the above-described backlash stroke L1 (see Fig. 7(e)), the pusher
6b biased from behind by the weak spring 6c abuts the rocker handle 1e of the circuit
breaker, but the rocker handle 1e remains halted in the OFF position, the limit switch
8a escapes from the cam groove 6f of the sliding base 6, and the early closing contact
is closed (ON operation). By this means, the coil of the electromagnet incorporated
in the tripping unit 7 (see Fig. 2(a)) of the undervoltage tripping device is excited
by a current.
[0045] And, when rotation of the rotary handle 4 is continued from the position of Fig.
7(b) toward the ON position, the sliding base 6 presses the rocker handle 1e of the
circuit breaker which is integral with the pusher 6b, and midway in this movement
stroke, the toggling mechanism (see Fig. 8) of the open/close mechanism 1d of the
circuit breaker rapidly performs a reversal operation. By this means, the main circuit
contact receives the biasing force of the open/close spring of the toggling mechanism
and closes, and at the same time the rocker handle 1e reaches the stroke end shown
in Fig. 7(e), and halts at this ON position. The operation stroke of the rocker handle
1e accompanying this closing operation of the main circuit contact is indicated by
L2 in the figure.
[0046] Further, when the rocker handle 1e of the circuit breaker reaches the ON position,
the rotary handle 4 of the external operating handle device 2 passes the ON position
somewhat, as shown in Fig. 7(c), and after this overrun halts at the ON position of
Fig. 7(d). Further, accompanying this operation of the rotary handle 4, the sliding
base 6 and pusher 8b pass through Fig. 7(g) to halt at the position of Fig. 7(h).
The limit switch 8a of the early closing contact unit 8 holds the ON state even after
the main circuit contact of the circuit breaker has closed, and maintains an excitation
current in the electromagnet coil incorporated in the tripping unit 7 (see Fig. 2(a)).
[0047] As is clear from the above explanation, the undervoltage tripping device of this
embodiment combines a tripping unit 7 and an early closing contact unit 8, and so
can exhibit the same operations and functions as the undervoltage tripping device
with an early closing contact described in Patent Reference 2. Moreover, there is
no need to install a dedicated rotary handle in the circuit breaker which links to
the early closing contact, as described in Patent Reference 2, and merely by somewhat
modifying the sliding base of the external operating handle device and additionally
external mounting the above early closing contact unit 8 on this external operating
handle device, an existing internal type undervoltage tripping device (see Patent
Reference 1) can be used as-is, and optional specifications for an undervoltage tripping
device with an early closing contact function can be accommodated by simple means.
By this means, circuit breaker manufacturers can reduce the number of optional products
prepared as auxiliary devices for undervoltage tripping devices compared with previously,
and costs entailed in stocking and management of such products can be reduced.
INDUSTRIAL APPLICABILITY
[0048] As described above, in an auxiliary device of a circuit breaker of this invention,
an optional product related to an undervoltage tripping device is divided into a plurality
of units and configured in advance, and units selected according to option specifications
specified by a user can be combined and used with a circuit breaker, to enable accommodation
of specifications with various options specified by simple means.
EXPLANATION OF REFERENCE NUMERALS
[0049]
- 1
- Circuit breaker
- 1a
- Circuit breaker case
- 1e
- Rocker handle
- 2
- External operating handle device
- 3
- Base
- 4
- Rotary handle
- 6
- Sliding base
- 6b
- Pusher
- 6c
- Spring
- 6f
- Cam groove
- 7
- Tripping unit
- 8
- Early closing contact unit
- 8a
- Limit switch
- 8b
- Frame
- 8e
- Support leg