Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-08-10
2001-12-18
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S641000, C340S654000, C340S657000, C340S664000, C361S029000, C361S031000, C361S093500, C361S094000, C361S115000, C361S118000
Reexamination Certificate
active
06331821
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a housing for a combination current sensor and relay.
One of the trends in many industrial environments is to use an ever increasing number of electrical devices that include small motors, such as motors incorporated with fans. Typically such small motors only draw a limited amount of current, such as 1-10 amps. To provide fault detection for electrical devices having limited current requirements, a current sensor is electrically interconnected with the power cable to the electrical device to sense the electrical load current. The current sensor may include an electrical interconnection to a remotely located control panel to provide a signal to the control panel representative of the current within the power cable. It is desirable to locate such a current sensor within a housing, such as a starter housing within a substation. The current sensor or an associated relay may be interconnected to a separate starter, if desired. A relay is typically electrically interconnected between the remotely located control panel and the electrical device to receive a control signal from the control panel and in response selectively enable or disable power to the electrical device. Like the current sensor, such a relay may be located within the starter housing. In addition, the relay may function as the starter if the power rating of the relay is appropriate. Because of decreasing starter housing sizing, the relay and current sensor may be enclosed within a single unitary housing. Such a device is disclosed in U.S. Pat. No. 5,808,846, incorporated by reference herein.
Referring to
FIG. 1
, Functional Devices, Inc. of Russiaville, Ind., manufacturers a Model RIBXLSA combination current sensor and relay
10
. Referring to
FIG. 1
, the device
10
includes a start/stop relay
12
that is energized or otherwise controlled by the digital output of a controller
14
. Power from a power source
16
is provided by a wire
18
which is interconnected to the start/stop relay
12
of the device
10
. The start/stop relay
12
is likewise interconnected to an internal sensor
20
by a wire
22
, namely, a current sensor in the form of a transformer. The output of the internal sensor
20
is interconnected to a load
24
by a wire
26
. The load
24
is interconnected to the source
16
by a wire
28
. Accordingly, a loop for current flow is provided by wire
18
, the start/stop relay
12
, the wire
22
, the internal sensor
20
, the wire
26
, and the wire
28
. When the start/stop relay
12
is open, as a result of the controller
14
, the power to the load
24
is interrupted (open circuit). Likewise, when the start/stop relay
12
is closed, as a result of the controller
14
, power is provided to the load
24
(short circuit). Accordingly, the controller
14
may control power to the load
24
by energizing and de-energizing the start/stop relay
12
. The device
10
may include a closed/open/auto switch
21
for enabling the operation of the start/stop relay
12
. Other applications of the device
10
, are illustrated in
FIGS. 2 and 3
. A solid state switch
21
measures the current level to the load
24
and provides an open/closed signal to the controller
14
based on the current level.
Referring to
FIG. 4
, the combination current sensor and relay
10
Model RIBXLSA from Functional Devices, Inc. is packaged in a rectangular housing
40
with a threaded opening
42
on the lower portion though which are passed a pair of wires
18
and
26
. The wires
18
and
26
are connected in series with the power cable to the load as shown in
FIGS. 1-3
. Internal to the housing
40
are a set of four wire connectors
110
to which the control wires to the controller
14
are attached. To access the four wire connectors
110
the rear panel
44
is removed. The control wires may be passed through an opening
46
in the upper left hand side, an opening
48
in the upper right hand side, or both, as desired. The textual and graphical indication for which connectors correspond to the solid state switch
21
and to the relay
12
are provided on the back panel of the device. A set of three light-emitting-diodes
50
,
52
and
54
are provided on the top of the housing
40
. The right hand diode
54
provides an indication as to whether the relay is energized. The left hand pair of diodes
50
and
52
provides assistance in adjusting the set point for the current level of the solid state switch
21
. When the central diode
54
is activated the current is over the trip point. When the left hand diode
50
is activated the current is under the tri point. A potentiometer that is accessed within the housing
40
when the back
44
is removed adjusts the set point for the switch
21
. The switch
21
includes some hysteresis. To adjust the device
10
, the potentiometer is decreased (turned counterclockwise) until the central diode
52
turns on (may already be on). The potentiometer is then increased (turned clockwise) until the left hand diode
50
turns on. Then the potentiometer is decreased (turned counterclockwise) until the central diode
52
turns on. This properly adjusts the current level. The instructions for adjusting and the meaning for the light emitting diodes are provided within the housing
40
. A closed/open/auto switch
56
is provided on the left hand panel of the housing
40
. Likewise, the instructions for the settings of the switch
56
are provided on the back panel of the housing
40
. The entire housing
40
is secured to a wall by a set of four screws at the corners thereof.
SUMMARY OF THE INVENTION
The present invention overcomes the aforementioned drawbacks of the prior art by providing a combination current sensor and relay with an improved housing. The housing has several aspects which result in improved functionality. In one aspect, the housing includes light emitting diodes on an upper surface that indicate open circuit and short circuit conditions. In another aspect, the housing includes a securement structure for a circuit board that includes the transformer and switches for device operation, together with aligned openings therein for routing wires to external devices. In another aspect, a multiple position switch is included on the upper surface that indicates multiple modes of operation of the device. In another aspect, the housing may be assembled in multiple parts by affixing a first portion to a support, a circuit board to the first portion, and a second portion to the first portion. In another aspect, the housing is suitable for engagement to alternatively a junction box and a duplex box. In another aspect, the configuration of the upper surface provides usability advantages.
REFERENCES:
patent: 4124030 (1978-11-01), Roberts
patent: 5502374 (1996-03-01), Cota
patent: 5808846 (1998-09-01), Holce et al.
patent: 6005760 (1999-12-01), Holce et al.
Bowman Mark
Holce Kent
Morey Frank
Rupert Matt
Chernoff Vilhauer McClung & Stenzel LLP
Nguyen Tai T.
Veris Industries, Inc.
Wu Daniel J.
LandOfFree
Combination current sensor and relay does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Combination current sensor and relay, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Combination current sensor and relay will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2590605