U.S. patent number 3,693,045 [Application Number 05/011,202] was granted by the patent office on 1972-09-19 for illumination.
This patent grant is currently assigned to The Edwin F. Guth Company. Invention is credited to Lorenzo S. Price.
United States Patent |
3,693,045 |
Price |
September 19, 1972 |
ILLUMINATION
Abstract
Illumination system utilizing H.I.D. (high intensity discharge)
lamps, and having a subordinate lamp automatically activated to
establish immediate illumination when the H.I.D. lamp circuit is
turned on, i.e., without awaiting the usual warm-up period, and to
maintain illumination during periods of voltage dip (which normally
extinguishes H.I.D. lamps) in the circuit supplying them, as well
as during subsequent recovery and restarting the H.I.D. lamps after
extinguishment as a result of voltage dip or other outage
condition.
Inventors: |
Price; Lorenzo S. (Creve Coeur,
MO) |
Assignee: |
The Edwin F. Guth Company (St.
Louis, MO)
|
Family
ID: |
21749294 |
Appl.
No.: |
05/011,202 |
Filed: |
February 13, 1970 |
Current U.S.
Class: |
315/91; 315/92;
315/87 |
Current CPC
Class: |
H05B
41/46 (20130101); H05B 41/231 (20130101) |
Current International
Class: |
H05B
41/46 (20060101); H05B 41/20 (20060101); H05B
41/14 (20060101); H05B 41/231 (20060101); H05b
039/10 () |
Field of
Search: |
;315/87,91,88 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kaufman; Nathan
Claims
Having thus described the invention, what is claimed and desired to
be secured by Letters Patent is:
1. A lighting fixture and circuitry for an illuminating system
comprising in combination: a reflector, a first receptacle for
accommodating a high intensity discharge lamp having a light
emitting surface disposed within said reflector, a second
receptacle for accommodating a lamp of different type having a
light emitting surface disposed within said reflector, said first
receptacle and second receptacle being connected to a normal source
of voltage supply and subordinate source of voltage supply
respectively, a transformer having a primary winding connected to
be energized by said normal source of supply, and a secondary
winding connected to feed said high intensity discharge lamp, a
capacitor intervening said secondary winding and said high
intensity discharge lamp, a diode connected in parallel circuit
relation with said high intensity discharge lamp, said diode being
connected on the side of said capacitor remote from said secondary
winding, and being normally disposed for conducting charge in a
direction towards said capacitor, a first relay coil connected in
parallel circuit relation with said high intensity discharge lamp,
said coil being connected on the side of said capacitor remote from
said secondary winding and being in series circuit relation with
said diode, said diode designed for interrupting the flow of
current to said relay coil when the voltage condition across said
diode senses a voltage condition signifying extinguishment of said
high intensity discharge lamp, said subordinate source of voltage
supply being substantially independent of said normal source of
voltage supply and connected to selectively energize said lamp of
different type, normally closed relay contacts responsive to said
relay coil controlling the flow of current between said subordinate
source of supply and said lamp of different type, said relay
contacts being normally closed to provide for conduct of charge
from said subordinate source of voltage supply to said lamp of
different type during initial ignition of said high intensity
discharge lamp until it emits normal light, and said relay coil
responsive to the voltage condition across said diode for opening
said relay contacts when the voltage across said high intensity
discharge lamp is within the range at which it emits normal light.
Description
The invention relates to illumination, and particularly to a system
which utilizes H.I.D. (high intensity discharge) lamps, and to a
fixture embodying such system.
H.I.D. lamps are being widely used in industrial and commercial
lighting, as well as in street lighting, but they are possessed of
certain characteristics which render them undesirable where
instantaneous and continuous illumination is required. The source
of illumination in such lamps is a translucent envelope charged
with ionizable gas usually argon, and containing a modicum of metal
or metal compound, such as mercury, sodium, or a metal halide,
which is conductive when cold (i.e., in its liquid or solid state)
but is vaporizable, in time, when a sufficient voltage is impressed
across the electrodes at opposite ends of the translucent envelope.
After energization of an H.I.D. lamp at the appropriate voltage,
the time required for the contents of the envelope to begin to emit
substantial light is noticeably long to persons accustomed to the
instantaneity of incandescent light. The time lag varies with the
materials employed, e.g., 2 minutes with sodium, 4 minutes with
mercury, and up to 20 minutes with the halides. Such slow starting
breeds impatience and dissatisfaction with the lighting system.
Furthermore, H.I.D. lamps are prone to "go out" when the voltage
with which they are energized dips to about 70 percent or less of
normal root-mean-square value for a time period of 30 micro-seconds
(0.000030 of a second); and after they "go out", there is a
substantial delay, even if normal voltage is restored within a
second, during which the vaporized cold-conductive material within
the envelope must first cool to condense, and thereafter be
reheated to vaporize before substantial light emission is resumed.
As an antidote for such unexpected and unwanted periods of
darkness, it has heretofore been proposed to provide areas normally
illuminated by H.I.D. lamps with an independent incandescent lamp
lighting system, which may be activated to bring darkness into
light while the H.I.D. illumination is in default. Such activation,
even if accomplished by remote control, must, as a practical
matter, be manually initiated, and hence requires not only time
(sometimes more time than it takes for H.I.D. lamps to cool,
recover, and relight), but groping in the dark to find the right
switch to throw or button to press. It has also been proposed to
provide, in the area to be illuminated by H.I.D. lamps, a
photoelectric cell which is constructed and arranged to turn on the
auxiliary incandescent lamp system after the cell senses darkness,
but since the photoelectric cell cannot discern whether the light
impinging upon it is emanating from an H.I.D. lamp or from an
incandescent lamp, it will either not turn off the incandescent
lamp system when the H.I.D. system comes back on, or it will
immediately turn off the incandescent system which it has just
turned on, unless it is in some way shieled from light emanating
from the incandescent sources, a condition which is difficult, if
not impossible, to achieve if both the H.I.D. lamp and the
auxiliary incandescent lamp are housed in the same reflector.
It is therefore an object of the present invention to provide an
H.I.D. illumination system, and a lighting fixture involving the
same, which will automatically turn on a subordinate incandescent
lamp system during starting of the H.I.D. system, as well as when a
voltage dip of magnitude such as to cause extinguishment of the
H.I.D. lighting system is sensed; and will automatically turn off
the subordinate system when the H.I.D. system comes back on.
To accomplish the aforesaid object, the invention contemplates the
provision of a subordinate system for energizing one or more
incandescent lamps (or other non-H.I.D. lamps) from a source which
may be, but is not necessarily, independent of the source which
energizes the H.I.D. lamps in the system, except that activation
and deactivation of the subordinate incandescent lamp system is
controlled by the transitory voltage condition at the H.I.D. lamps.
The subordinate system may, if desired, make use of one, both or
none of the line conductors which supply energy to the H.I.D. lamp
system. More specifically, the invention contemplates the
provision, in an H.I.D. lamp system, of a voltage sensing means
connected between opposite legs of the supply line from which one
or more H.I.D. lamps are energized. In particular, the voltage
sensing means may be any instrumentality or combination of
instrumentalities which serve to keep the subordinate incandescent
lamp system in open-circuit condition, as long as the voltage drop
in the H.I.D. lamp or lamps is within the range required for the
H.I.D. lamp to continuously emit light, but which operates to
energize the subordinate incandescent lamp circuit when the voltage
drop across the H.I.D. lamp or lamps departs from the aforesaid
range. Typical of the instrumentalities suitable for the purpose
are relays, diodes, semi-conductors and combinations of the same.
For example, two relays, each having a coil and a set of normally
closed contacts, may be provided, with the coil in each relay
separately connected across the legs of the H.I.D. lamp energizing
circuit, and in parallel circuit relation with the lamp or lamps;
the contacts of one relay being in series circuit relationship with
the coil of the other relay, and the contacts of the other relay
being in series circuit relationship with the lamp or lamps in the
subordinate incandescent lamp circuit. Of course, the two relays
may be embodied in the same apparatus as long as the contacts of
one control the flow of current to the coil of the other.
Alternatively, in substitution for the first-mentioned relay, an
appropriate diode or semi-conductor may be inserted in place of the
coil and contacts of the first-mentioned relay in series with the
coil of the second-mentioned relay.
Given a system of the kind described in the preceding paragraph, a
lighting fixture embodying the same may typically comprise an
H.I.D. lamp with appropriate receptacle, and an incandescent lamp
with appropriate receptacle, both mounted within the same reflector
located in a housing which also encloses the ballast (transformer
and capacitor) commonly used for the energization of an H.I.D.
lamp, together with the relays, or other instrumentalities provided
for automatically energizing the incandescent lamp as and when a
voltage condition, which causes the H.I.D. lamp to fail or cease to
emit light, prevails even momentarily.
The accompanying drawings illustrate a typical embodiment of the
invention in a lighting fixture, and diagrammatically illustrate
the voltage conditions likely to occur in an H.I.D. lighting system
which create the utility for the invention, as well as schematic
illustrations of the circuitry involved in several embodiments.
In the drawings:
FIG. 1 is a representation of an oscillogram illustrating the
conditions which may be expected to exist, on occasions, in an
H.I.D. illuminating system, the existence of which conditions is
sensed, in accordance with the invention, to activate the
subordinate incandescent lamp system;
FIG. 2 is a diagrammatic view of a typical H.I.D. lamp circuit
forming a part of the prior art;
FIG. 3 is a schematic diagram of one embodiment of the circuitry
involved in a lighting system organized and arranged in accordance
with the present invention;
FIG. 4 is a schematic diagram of the circuitry involved in a
further embodiment of the invention but showing only one fixture;
and
FIG. 5 is a vertical sectional view of a lighting fixture embodying
the invention.
The oscillogram of FIG. 1 illustrates in full lines the voltage
drop across an H.I.D. lamp while current is flowing through it
under various normal and abnormal conditions which may be expected
to occur; and in broken lines the potential differing between
opposite terminals of the H.I.D. lamp while voltage is available
at, but no current is flowing through, the lamp. As mentioned
previously, when an H.I.D. lamp is "cold" (i.e., below the
temperature at which the cold-conductive metal or halide is
vaporized), its electrical resistance is low (and hence when
current flows through the lamp, the voltage drop within the lamp is
low) and such "starting" conditions are illustrated in zone A of
FIG. 1, where only a few cycles of voltage are plotted, but those
skilled in the art will understand that hundreds occur during the
warm-up period in which the cold-conductive metal or halide is
vaporized. With H.I.D. lamp wherein mercury is the cold-conductive
element, the "warm-up" period A may be expected to endure for about
four minutes before the mercury has vaporized, or the lamp emits
measurable light. Once the cold-conductive element of the H.I.D.
lamp has vaporized, the conductivity of the lamp decreases sharply,
and the amplitude of the voltage wave shown at zone B of the
oscillogram illustrates, vis-a-vis zone A, the relative magnitude
of the voltage drop across the H.I.D. lamp during normal light
emission. The duration of zone B is normally as long as the
management desires light, but abnormalities do occur without
advance notice, and, as hereinbefore mentioned, a supply voltage
dip D to 70 percent of normal for a miniscule part of a second will
not only extinguish the arc in an H.I.D. lamp, but render it
temporarily non-conductive. When such occurs, the lamp must undergo
a "cooling-off" period C, during which no current can flow through
it. The duration of the "cooling-off" period depends not only upon
ambient thermal conditions, but upon the time required for the
vaporized cold-conductive element to recondense to its cold state
of liquid or solid, and become sufficiently conductive to be
re-vaporized. The "cooling-off" period may endure for as much as
twenty minutes after the occurrence of a voltage dip, or other
momentary power outage. Regardless of the duration of the
"cooling-off" period, once conductivity is restored, the lamp must
go through a repetition of the initial warm-up period, represented
in FIG. 1 as zone A', before restoration of normal light emission
as represented by zone B' in FIG. 1. Zones A, C and A' are
cross-hatched to connote darkness, in contrast with zones B and B'
wherein the H.I.D. lamp is normally operating to emit light.
The circuitry for a conventional H.I.D. lamp system of the prior
art is illustrated in FIG. 2 of the drawings, where an H.I.D. lamp
1 is energized from a remote source of power such as a generator 2,
stepped up to transmission voltage by a transformer 3, and then, in
reasonable proximity to the locus of the lighting system, stepped
down from transmission voltage to distribution voltage by a
transformer 4. From the secondary of transformer 4, a feeder
conductor 5, through switch 50, supplies power to the H.I.D.
lighting system, and perhaps other instrumentalities. The system
for energizing a single H.I.D. lamp, such as 1, involves a ballast,
usually in the form of an auto transformer 6, connected for
energization between conductor 5 and a ground or neutral conductor
7. The auto transformer 6 has its secondary connected through
conductor 8 to a capacitor 9, and from there through a conductor 10
to one side of H.I.D. lamp 1, the other side thereof being
connected to ground or neutral conductor 7 in parallel circuit
relationship with the primary of the auto transformer 6. As
mentioned previously, conductor 5 may be connected to energize
other H.I.D. lamps than 1 or other instrumentalities, as, for
example, through branch conductors 11, 12, 13 and 14. The present
invention utilizes all of the circuitry and instrumentalities
illustrated in FIG. 2, but adds thereto the control
instrumentalities necessary to sense the voltage condition in the
circuitry of FIG. 2, which either will produce, or has just
produced, a condition wherein the H.I.D. lamp is not emitting
light, despite the fact that full voltage is available at it; and
the above-mentioned control instrumentalities are of a character
such that when they sense such conditions, they automatically
complete a circuit to a subordinate lamp, such as an incandescent
lamp, from a subordinate source of power, which may be wholly
independent of the generator 2 (as, for example, a battery source
or a stand-by generator), or may be supplied from generator 2
through a different distribution transformer than 4.
Turning now to FIG. 3 for an illustrative embodiment of the
circuitry involved in the automatic activation and control of the
subordinate lighting system of the present invention, it will be
observed that the whole of the circuitry shown in FIG. 2 is
utilized, and the same reference characters designate corresponding
elements thereof, but the circuitry commencing with the
auto-transformer 6 is duplicated to show a system embodying a
plurality of H.I.D. lamps and subordinate incandescent lamps, in
contrast with the single lamp system of FIG. 2.
Essentially, the circuitry and instrumentalities which FIG. 3 adds
to that of FIG. 2, includes a subordinate source of electrical
energy illustrated as a battery 15, one side of which is grounded,
a conductor 16 extending from the battery 15 to a branch 17 which
is permanently connected to contact 18 of a relay 19 having a coil
20, and also having an opposite contact 21 which is permanently
connected, through a conductor 22, with one side of an incandescent
lamp 23, the other side of which is permanently connected with the
neutral or ground conductor 7 which also forms a part of the
circuitry shown in FIG. 2. The coil 20 of relay 19 is connected in
parallel circuit relation with H.I.D. lamp 1, but the contacts 18
and 21 thereof are biased to a position whereat the circuit between
contacts 18 and 21 is normally closed, but whenever coil 20 of the
relay is energized to a voltage which is critical in the operation
of the H.I.D. lamp 1, the circuit between contacts 18 and 21 is
automatically opened. The aforesaid critical voltage is that which
prevails when the H.I.D. lamp 1 is emitting normal light. The
additional circuitry and instrumentalities also include a means for
sensing another critical voltage condition at H.I.D. lamp 1, and is
illustrated in FIG. 3 as a relay 24, whose contacts 25 and 26 are
normally closed, but under an abnormal condition, are opened by the
energization, at the last-mentioned critical voltage, of coil 27.
The last-mentioned critical voltage condition occurs when the
voltage at opposite terminals of the H.I.D. lamp exceeds the range
which prevails while the H.I.D. lamp 1 is emitting normal light,
as, for example, when the H.I.D. lamp is extinguished by the
occurrence of a voltage dip, whereupon no current flows through the
lamp, with the result that the potential difference between the
lamp terminals substantially exceeds the voltage drop through the
lamp while emitting normal light. In other words, when H.I.D. lamp
1, despite the availability of voltage at it, is not conductive, as
during periods of cooling-off after a voltage dip, the voltage on
coil 27 of relay 24 is higher than when the H.I.D. lamp is emitting
normal light, and it is during such periods of inordinately high
voltage on relay coil 27 that the circuit for energizing coil 20 of
relay 19 is opened by the separation of contacts 25 and 26 of relay
24. When the contacts 25 and 26 are thus separated, the circuit
from conductor 10 through conductor 28 to coil 20 of relay 19 is
interrupted, and contacts 18 and 21 close to complete a circuit to
the incandescent lamp 23 from battery 15 through conductors 16, 17,
22 and ground 7. On the other hand, when H.I.D. lamp 1 is emitting
normal light, the voltage on relay coil 27 is inadequate to
interrupt the electrical connection between contacts 25 and 26, and
thus coil 20 of relay 19 is energized to maintain its contacts 18
and 21 separated. Those skilled in the art will understand that the
functions of the separate relays 19 and 24 may be accomplished by a
single relay device having two coils and two pairs of contacts.
As mentioned previously, the embodiment shown in FIG. 3 involves a
plurality of H.I.D. lamps in which the several instrumentalities
above described are duplicated; and the duplicates are designated
by a three-digit reference character whose last digit or two
corresponds to the one or two digit reference numerals previously
referred to, e.g., relay 106, capacitor 109, conductor 110, H.I.D.
lamp 101, incandescent lamp 123, relay 124, relay 119 are,
respectively, duplicates of the parts hereinbefore designated 6, 9,
10, 1, 23, 24, and 19.
As indicated hereinbefore, the relay 24 may be replaced by a diode,
and FIG. 4 illustrates the circuitry of a system employing such,
and utilizing the same reference characters as those shown in FIG.
3 for identical parts. In this embodiment, a diode 29 is connected
in series with coil 220 of relay 219. The diode is selected so as
to become conductive in the direction from conductor 16 toward
conductor 7 when the voltage drop across the H.I.D. lamp reaches
the normal operating value, i.e., when the lamp is emitting light
in the normal way; and the diode remains so conductive at voltages
in excess of the normal operating value. While thus conductive, the
diode permits current to flow from conductor 10 through coil 220 of
relay 219 to thereby open the normally closed contacts 218 and 221
thereof, and thereby disconnect the incandescent lamp 223 from its
source of power 15. On the other hand, diode 29 is always
conductive in the direction from conductor 7 toward conductor 10,
but when: during "starting" the voltage drop across H.I.D. lamp 1
is substantially lower than the normal operating voltage drop
thereacross; the current traversing coil 220 is insufficient to
open the normally closed contacts 218 and 221, and during "cooling
off," after a voltage dip which extinguishes H.I.D. lamp 1 (at
which time that lamp is traversed by no current), no current can
traverse coil 220 and consequently contacts 218 and 221 remain in
their normally closed position at which they connect incandescent
lamp 23 to its source of power 15.
The invention also envisions a composite lighting fixture which
includes the voltage sensing and control instrumentalities of the
system illustrated by FIGS. 3 and 4. Such a fixture is shown in
FIG. 5, where the circuitry and control instrumentalities
correspond to the system schematically illustrated in FIG. 3. Such
a fixture may comprise a housing 30, whose lower end is open and
provided with a suitable lens 31, above which is mounted a suitable
reflector 32. At the upper end of the housing, there is mounted in
one corner an auto-transformer corresponding to that of FIG. 3, and
in the opposite corner, a capacitor 9 corresponding to that of FIG.
3. At top center of the housing, a receptacle 33 is mounted to
accommodate H.I.D. lamp 1, with its light-emitting surface disposed
wholly within reflector 32, and its neck and base extending through
a hole 34 in the crest of said reflector. Similarly, a receptacle
35 is mounted in the lower righthand corner of the housing 30 to
accommodate an incandescent lamp 23, whose neck projects through a
hole 36 in the reflector. At right center, there is mounted a
composite relay 37 which, in a unitary housing, includes the
counterparts of relays 19 and 24 of FIG. 3. Hence, the composite
relay 37 has four contact terminals 38, 39, 40 and 41, which
correspond, respectively, with contacts 26, 25, 18 and 21 of FIG.
3. The several conductors which interconnect the transformer 6, the
capacitor 9, the coils of composite relay 37, the terminals of
relay 37, the sockets 33 and 34, bear the same reference characters
as the corresponding conductors in FIG. 3. It will be understood
that the composite relay 37 may be replaced by the single relay 219
and diode 29, and the fixture wired in accordance with FIG. 4.
The number of the fixtures which may be energized from the same
feeder 5 and the same subordinate source through the same conductor
16, in the manner shown in FIGS. 3 and 4, is limited only by the
magnitude of the respective sources of power and the respective
conductors. In fact, given a ballast (transformer 6, and capacitor
9) capable of simultaneously serving a plurality of H.I.D. lamps,
one set of the voltage sensing and control instrumentalities, such
as relays 19 and 24 or diode 29 and relay 219, is sufficient for a
plurality of H.I.D. lamps and subordinate incandescent lamps
connected in parallel circuit relation, respectively, across
conductors 7 and 10, and across conductors 7 and 16.
Those skilled in the art will understand that when the H.I.D. lamp
1 is emitting normal light (i.e., when current traverses the lamp
as an arc), the voltage drop across it in a typical case may be 90
to 135 volts R.M.S., which is greater than the voltage drop (e.g.,
10 to 50 volts R.M.S.) across the lamp when it is "starting" from
cold (i.e., when current traverses the lamp by conduction through
the cold-conductive element while in the liquid or solid state),
but less than the potential difference (e.g., 220 volts R.M.S.)
between opposite terminals of the lamp when the lamp is "cooling
off" after a voltage dip has extinguished it (i.e., when, despite
the availability of normal voltage at it, no current traverses the
lamp) because the cold-conductive element is in the vapor state.
Hence, in the embodiment of FIG. 3, the coil 27 of relay 24 may be
calibrated to open its normally closed contacts 25-26 (thereby to
de-energize coil 20 of relay 19 and release its contacts 18 and 21
to their normally closed position) when the potential difference
between opposite terminals of the H.I.D. lamp 1 is substantially in
excess (e.g., 220 volts) of the normal operating voltage drop
(e.g., 90 to 135 volts) across the lamp; and under such conditions,
the subordinate source of power 15 is automatically connected with
the incandescent lamp 23. Similarly, the coil 20 of relay 19 is
calibrated to open its normally closed contacts 18 and 21 whenever
the voltage across its coil is equal to or greater (e.g., 90 volts)
than the voltage drop across the H.I.D. lamp when it begins to emit
normal light; and under such conditions, the subordinate source of
power 15 is automatically disconnected from the incandescent lamp
23.
Thus, it is apparent that when the switch 50 is closed, after
having been open for a period sufficient to permit the H.I.D. amp 1
to cool enough that its cold-conductive element is condensed, the
high conductivity of the lamp during "starting" produces such a low
voltage drop across it that the relay coil 20 is insufficiently
energized to enable it to open the normally closed contacts 18 and
21 thereof. Consequently, the incandescent lamp 23 is energized
simultaneously with the closing of switch 50, and remains energized
until the arc strikes in the H.I.D. lamp and the lamp begins to
emit normal light. At that time, the voltage drop in the H.I.D.
lamp attains a value such that coil 22 of relay 19 is sufficiently
energized to pull open the normally closed contacts 18 and 21, and
thereby disconnect the incandescent lamp 23 from the subordinate
source 15. The latter condition normally continues until switch 50
is deliberately opened unless, in the meantime, there occurs a
voltage dip of magnitude such as to extinguish the H.I.D. lamp,
whereupon, in the cooling-off period, the potential difference
between opposite terminals of the H.I.D. lamp becomes the voltage
across coil 27 of relay 24, thereby opening its normally closed
contacts 25 and 26, and de-energizing coil 20 of relay 19 so that
its normally closed contacts assume the position whereat the
incandescent lamp is energized from the subordinate source, as
previously described.
While two embodiments of circuitry suitable for use in accordance
with the present invention have been disclosed in detail, and
variations thereof have been indicated in the foregoing
description, it is to be understood that the invention is not
limited to the details of those embodiments. On the contrary, it is
recognized that persons of ordinary skill in the art will readily
envision other variations and modifications of the circuitry and
system without departing from the spirit of the invention, and
accordingly, it is to be understood that the invention is not
limited to the details of the foregoing disclosure.
* * * * *