Electrical connectors – With insulation other than conductor sheath – Insulating body having plural mutually insulated terminals...
Reexamination Certificate
2000-06-02
2003-03-11
Ta, Tho D. (Department: 2833)
Electrical connectors
With insulation other than conductor sheath
Insulating body having plural mutually insulated terminals...
C439S532000, C439S082000, C361S634000, C361S644000, C361S648000, C361S652000
Reexamination Certificate
active
06530811
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a DC distribution module for mounting a plurality of overcurrent protection devices, such as circuit breakers or fuse modules. More particularly, the present invention is directed to an assembly of one or more modular busbar modules for mounting a plurality of plug-in circuit breakers and fuse modules, wherein the busbar modules contain female receptacles for line and load male plugs, also known as positive and negative power terminals, along with female plugs for auxiliary alarm contact terminals.
BACKGROUND OF THE INVENTION
There are numerous electrical system applications which require the use of a plurality of overcurrent protection devices, such as circuit breakers or fuse modules, to shut off current in one or more portions of the electrical system in response to an overcurrent condition. Fuses typically have a conductive wire element that rapidly heats and melts in response to an overcurrent condition, forming an open circuit. Fuses are often packaged in fuse modules containing additional circuit elements which transmit an alarm signal if the fuse opens in response to an overcurrent condition. Circuit breakers commonly comprise a movable electrical breaker contact and a stationary breaker contact. The movable electrical contact is typically coupled to an actuator mechanism that utilizes an electromagnetic device to open the breaker contacts when an over-current condition is detected. During normal circuit operation, the actuator mechanism electrically couples the breaker contacts so that the circuit breaker is in a conducting, or on-state. However, when an over-current condition is detected, the circuit breaker trips, and enters a non-conducting, or off-state. A handle on the external surface of the circuit breaker is commonly coupled to the actuator mechanism. The actuator-handle provides a visual indication of the state of the circuit breaker (e.g., on, tripped, and off) while also permitting the user to reset the circuit breaker after the circuit breaker has been tripped or to deliberately turn the circuit breaker off during routine repair or maintenance. Some circuit breakers include an additional alarm circuit, which sends an alarm signal to other circuits when the alarm circuit senses that the circuit breaker has been tripped.
FIG. 1
shows a perspective view of a prior art circuit breaker module
100
used in a power distribution module. A plurality of circuit breakers
110
,
120
,
130
are coupled by frictional forces or by mechanical connectors to base
180
and front face plate
122
. Each circuit breaker
110
,
120
,
130
has a corresponding actuator handle
105
. As shown in
FIG. 1
, screw connectors
131
are commonly used to electrically couple circuit breakers
110
,
120
,
130
to busbars
162
,
164
and connectors
160
,
161
,
151
to couple current to a rear connector
134
on panel
124
. Bus bars
162
,
164
couple a negative polarity power terminal, often called a line terminal, of each circuit breaker
110
,
120
,
130
to a negative power terminal. Connectors
160
,
161
,
151
separately couple the load terminal, often called the positive power terminal, of each circuit breaker
110
,
120
,
130
to separate electronic loads.
While circuit breaker module
100
provides the benefit of several circuit breakers
110
,
120
,
130
arranged to control the current or power in different portions of a power distribution module, it has several drawbacks. One drawback is that it may be inconvenient to replace one of the circuit breakers
110
,
120
,
130
. Replacement of circuit breakers may be required if a circuit breaker is damaged. Additionally, circuit breakers may need to be replaced if it is determined that a different response is required by the circuit breaker. For example, the user may determine that a higher amperage circuit breaker is required for a particular application. The time to replace a circuit breaker
110
,
120
,
130
in module
100
may be significant because the total time to replace a circuit breaker includes the time to: 1) withdraw the module; 2) remove any exterior housing elements surrounding the screw connectors
131
; 3) disconnect the screw connectors
131
; 4) extract the old circuit breaker; 5) insert a new circuit breaker; 6) connect screw connectors
131
to the new circuit breaker; 7) attach any exterior housing elements; and 8) re-insert module
100
.
Another drawback with circuit breaker module
100
is that the housing and connector are comparatively bulky. There is a general trend to miniaturize all aspects of power supply and power distribution systems. Unfortunately, the total volume of circuit breaker module
100
, including connectors
131
; busbars
162
,
164
; and connectors
160
,
161
,
151
is significant.
Still another drawback with module
100
is that it does not address the problem of circuit breakers with alarm circuits. Circuit breakers with alarm circuits typically have additional auxiliary terminals for sending an alarm signal that is indicative of the operating state of the circuit breaker. For example, an alarm circuit preferably sends a logical “high” signal from an alarm terminal to indicate that the circuit breaker has been tripped due to an overcurrent event. The alarm signal may, for example, be used to trigger an indicator light to alert the user that a circuit breaker has been tripped. Circuit breakers have two alarm contact terminals. More commonly, however, circuit breakers have three alarm contact terminals corresponding to normal-off, normal-closed, and common terminals. An electrical connection must be provided to each alarm contact terminal of each circuit breaker of a circuit breaker module. Unfortunately, this increases the complexity of the electrical connection required in a circuit breaker module.
FIG. 2
is a prior art side-view drawing of a circuit breaker
210
with an alarm circuit
220
providing an alarm signal via stab-type alarm terminal
216
. Line contact
212
and load contact
214
also comprise stab-type connectors. Stab-type connectors are a type of connector that has a comparatively thin, blade-like connector surface which is pressed into a female connector slot or socket (i.e., “stabbed”) to form a tight mechanical and electrical coupling. Stab-type connectors have the advantage that the small surface area of a male stab-type connector permits a significant penetration pressure to be applied in inserting the male connector. However, stab-type connectors have the disadvantage of having a comparatively small cross-sectional area for current to flow.
FIG. 3A
is a perspective view of a prior art circuit breaker module
254
designed to be loaded with a plurality of circuit breakers
210
having stab-type line and load terminal connectors
212
,
214
(not shown) and stab-type alarm contact terminal connectors
216
(not shown) as illustrated on the circuit breaker
210
of FIG.
2
. For the purposes of illustration, three circuit breakers
210
are shown installed in a module
254
designed to hold a total of four circuit breakers. A busbar
288
is used to provide an electrical connection to line contacts
212
. Contacts
256
are spring-biased receptacles configured to contact load contacts
214
. Additional connector legs
282
facilitate installation of module
254
as an integral unit.
FIG. 3B
is a top view of module
254
with circuit breaker
210
removed, to more clearly show the electrical connectors. Each aperture
260
allows passage of a line contact
212
(not shown) in order to receive power from a power source. Spring biased alarm contacts
262
are dimensioned to mate with corresponding alarm terminals
216
(not shown) for respective circuit breakers
210
. The alarm contacts
262
are electrically connected to each other by alarm contact line
264
. Load connectors
258
provide a bolt and screw connection site to secure external electrical lines.
While circuit breaker module
254
provides several benefits, it has several drawbacks. One drawback of stab-type conn
Ghanem Imad
Mayer Denis
Padulo Michael
Astec International Limited
Coudert Brothers LLP
Ta Tho D.
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