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Патент USA US3089990

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May 14, 1963
F A. NEUSBAUM
3,089,980
BALLAST APPARATUS FOR STARTING AND OPERATING
ELECTRIC DISCHARGE LAMPS
Filed June 1, 1961
2 Sheets-Sheet 1
‘gas
May 14, 1963
F. A. NEUSBAUM
3,089,980
BALLAST APPARATUS FOR STARTING AND OPERATING
ELECTRIC DISCHARGE LAMPS
2 Sheets-Sheet 2
Filed June 1, 1961
47%
____________|
[/7 149/? 5'0)“:
Framz A. A/euséaum,
4527077769
United States Patent 0 "ice
1
3,089,980
Patented May 14, 1963
2
ionization potential voltage so that the ballast apparatus
3,089,980
BALLAST APPARATUS FOR STARTING AND
()PERATING ELECTRIC DISCHARGE LAMPS
Frank A. Neusbauni, Danville, Ill, assignor to General
Electric Company, a corporation of New York
Filed June 1, 11961, Ser. No. 114,063
llti (Ilairns. (Cl. 315-97)
can be operated from a grounded or ungrounded power
supply in conjunction with a grounded or ungrounded
?xture. For these various grounded and ungrounded
conditions of operation which are not infrequently en
countered in practice, the starting aid resistor has not
been entirely satisfactory. For example, in an installation
where the primary winding of the ballast transformer is
This invention relates to ballast apparatus for starting
connected to an ungrounded power supply and the ballast
and operating electric discharge lamps and more par 10 case is ungrounded, the starting aid potential was ac
ticularly to such a ballast apparatus for starting and op
tually decreased by an auxiliary starting aid circuit uti
erating gaseous discharge lamps such as ?uorescent lamps
lizing a resistor connected between the low potential end
employing an auxiliary starting aid circuit arrangement.
of the primary and the ballast case. Thus, in such an in
In most ?uorescent lamp lighting applications, the bal
stallation the starting resistor has a detrimental effect on
last apparatus for the lamp is mounted within the lamp 15 starting. Further, the starting aid resistor is an addi
?xture. Each ?uorescent lamp is positioned in a pre
tional component of the starting aid circuit and adds to
determined spaced relationship with the ?xture so that
the cost of the ballast apparatus. From a standpoint
a capacitive effect is produced between the lamp and the
of economy, it is, of course, desirable to reduce the num
?xture. Although a grounded conductive strip such as
ber of components used in any electrical circuit.
a narrow ribbon of silver graphite deposited on the lamp 20
Accordingly, it is a general object of my invention to
bulb may be used in the same manner as a lamp ?xture,
provide a new and improved auxiliary starting aid ar
the ?xture itself is generally used as a starting aid for
rangement for a ballast apparatus for operating one or
the lamp because it is a relatively inexpensive and simple
more gaseous discharge lamps.
arrangement.
Another object of my invention is to provide an im
The effect of grounding the ?xture or conductive plate 25 proved auxiliary starting aid circuit arrangement in a
and grounding one side of the low potential side of the
ballast apparatus wherein the need for an auxiliary start
ballast circuit is to place the lamp ?xture in electrical
ing aid resistor is eliminated.
connection with the lovar potential side of the ballast cir
A further object of my invention is to provide a new
cuit. Further, it will be understood that if the low po
and improved auxiliary starting aid circuit arrangement
30
tential side of the distribution line is grounded as is the
in a ballast apparatus wherein an increased starting aid
case in a normally grounded distribution system and if
potential is provided when the ballast circuit is operated
the ballast case and ?xture are grounded, no auxiliary
from a grounded and ungrounded power supply.
starting aid device will be needed in autotransformer
Brie?y stated, in accordance with one aspect of my in
connected ballast circuits. In the event the distribution
35 vention, I have provided a ballast apparatus having a
system is not effectively grounded, or in the event that
the lamp ?xture is not grounded, a starting aid resistor
is provided so that the low potential side of the ballast
circuit is in electrical connection with the ?xture and the
auxiliary starting aid circuit forms a complete loop. The
impedance provided by the resistor prevents a lethal cur
rent ?ow to the ballast case.
Ballast circuits which uti
lize isolated primary designs must use some auxiliary
means to return one end of the secondary circuit to the
ballast enclosure, regardless of whether the primary dis
tribution system is grounded.
The auxiliary starting aid circuit or loop is completed
through ground from the conducting ?xture to the low
potential side of the primary winding of the ballast trans
former. The low potential side of the primary is usually
high leakage reactance transformer and a power factor
capacitor connected in circuit with the secondary wind
ing thereof. The capacitor container is connected to
ground and the reactive impedance developed between
the capacitor container and the capacitor outer foil is
utilized in an auxiliary starting aid circuit. The lamp
or lamps energized by the ballast apparatus are posi
tioned in close proximity to a conducting ?xture and dis
posed in capacitive relationship therewith. The auxil
iary starting aid circuit applies at least the voltage devel
oped across the secondary winding across the lamp elec
trode and the ?xture capacitively coupled therewith. The
grounded connection to the capacitor container solely
provides a return path for the auxiliary starting aid cur
rent to the ballast apparatus. When the lamp is started,
Since 50 the reactive impedance between the capacitor case and
grounded through a resistor to the ballast case.
the ballast case is generally connected to the lamp ?xture,
the ?xture is thereby connected in electrical circuit with
the low potential side of the primary winding. Because
of the high impedance of the grounding resistor and of
the capacitive coupling between the lamp and ?xture,
only a small amount of current will ?ow in the starting
the capacitor outer foil is suf?cient to prevent any sig
ni?cant amount of current flow out of the ballast circuit.
The subject matter which I regard as my invention is
particularly pointed out and distinctly claimed in the con
cluding portion of this speci?cation. My invention, how
ever, both as to organization and mode of operation, to
aid circuit from the electrode to the ?xture. However,
gether with further objects and advantages thereof, may
this current is su?icient to increase substantially the ioni
be best understood by reference to the following descrip
zation of the gas in the vicinity of the lamp electrode.
tion taken in conjunction with the accompanying draw
The increased ionization potential in the vicinity of the 60 ings
in which:
lamp electrodes permits the lamp to be started with
FIG.
1 is a schematic diagram ballast apparatus in
lower starting voltages applied across the lamp terminals.
corporating the features of the present invention;
The starting voltage at the output terminals of the bal
FIG. 2 is a plan view of the ballast apparatus shown
last transformer is concurrently placed across the elec
65 schematically in FIG. 1 in which the circuit connections
trodes of the lamp with the starting aid potential until
have been omitted;_
the lamp is ignited. Once the lamp has ignited, the start
FIG. 3 is a schematic diagram of an improved ballast
ing aid circuit is substantially ineffective in the circuit be
apparatus for operating a pair of serially connected dis
cause of the high impedance of the capacitive coupling
charge lamps in accordance with the invention;
between the lamp and ?xture.
70
FIG. 4 is a plan view of the ballast apparatus shown
It is desirable that a ballast apparatus be provided
schematically in FIG. 3 wherein the circuit connections
wherein the starting aid circuit will provide a su?icient
have been omitted; and
3,089,980
3
FIG. 5 is a view partly in section of a power factor
capacitor such as is conventionally employed in a ballast
apparatus with the capacitor assembly partially-unrolled.
Referring now to the drawings and more speci?cally to
FIG. 1, a schematic circuit diagram of one form of appli
cant’s invention for operating a hot cathode type of ?uores
cent lamp L is shown. A ballast apparatus 10 is contained
within a ballast case 11 represented by dashed lines. The
ballast apparatus 113 includes a high reactance transformer
.4.
any other suitable ground, I have discovered that such an
arrangement is equivalent to connecting one end of the
secondary winding S in series circuit with one plate of the
capacitor 35, the other plate of which is connected to
ground. Thus, one end of the secondary winding S is
grounded through a capacitor by connecting the container
9 of capacitor 13 in electrical circuit with ballast case 11,
and the capacitive impedance in tr e circuit is isuf?cient to
prevent any appreciable current ?ow from the ballast appa
12, a power factor capacitor 15 having a metallic or con 10 ratus 10 to ground. Capacitor 13 has suf?cient capacitive
ductive container 9, and output leads 14, 15 connected to
reactance as compared with the inductive reactance of a
as to be icapacitively coupled therewith.
of input terminal leads 21, 22 for connection to a suitable
ballast transformer 12 to draw a leading current through
cathodes 16, 17 of lamp L. A grounded conductive plate
the secondary winding S. A bleeder resistor R may be
is identi?ed generally in FIG. 1 by reference numeral 18
connected across capacitor 13, if desired.
and in most applications is the lighting ?xture. Lamp L
As shown in FIG. 1, the primary winding P has a pair
is positioned in proximity to the conductive plate 18 so 15
A spacing of
approximately 3/8 of an inch may be employed between
the lamp L and the conductive plate 18.
The high reactance ballast transformer 12 includes a
alternating current supply line shown schematically by
the dashed lines 39, 4'19, the low potential side being shown
by the supply line at; which is grounded. Although the
magnetic core 19, a primary winding P, a secondary wind 20 invention is described in connection with an alternating
current supply that has one side grounded in accordance
ing S, cathode heating windings H1, Hz, a magnetic shunt
with the standard practice for normal residential and com
20 and input terminal leads 21, 22. As shown in FIG. 2,
mercial power distribution systems, the ballast apparatus
the primary winding P and the secondary winding 5 are
10 of the present invention can be operated from supply
placed side by side on a central winding leg 23 of the mag—
netic core 19 and are separated by magnetic shunts 20. It 25 sources which are not grounded.
During operation, the cathodes 16, 17 of ?uorescent
will be appreciated that the leakage reactance of the ballast
lamp L are continuously supplied with cathode heating
transformer 12 may be readily increased by the inclusion
current by the cathode heating windings H1, H2 which
of a high reluctance leakage path or shunts of magnetic
are closely coupled with the primary winding P and con
material between the primary winding P and the second
ary winding S. ‘In the exempli?cation of the invention 30 nected in circuit with the cathodes 16, 17 by leads 14, 41
and 15, 42, respectively. The high potential end of the
shown in FIGS. 1 and 2, the ?ux leakage path is formed
secondary winding S is connected with lamp L by the
of inserted shunts 20. A high leakage reactance trans
circuit means which includes the output lead 14. The
former is normally required in ballast circuits in order that
low potential end of the secondary winding S is connected
the current How in the lamp circuit be limited because the
discharge lamp L has a negative resistance characteristic. 35 with lamp ‘L by circuit means which includes the capacitor
It will be understood that ?ux leakage paths may be
formed either through nonmagnetic material, such as air,
or through magnetic material by the provision of project
ing shunt legs integrally formed with the yoke sections or
13 and output lead 15.
_ In FIG. 3, -I have illustrated a ballast apparatus 54) suit
able for operating a pair of fluorescent lamp L1, L2 capaci
tively coupled with a conductive plate or ?xture 48 con
The ballast apparatus 50 includes
the ballast case 51 shown schematically by the dashed
rectangle, a high reactance ballast autotransformer 55, a
power factor capacitor 56 and a starting capacitor 58 hav
ing a container 57, and output leads 59, 66.
The high reactance ballast transformer 55 includes a pri
45
insertable shunts 21) as are employed the illustrative em 40 nected to ground 49.
bodiment of the invention.
Referring again to FIG. 2, it will be seen that magnetic
core 19 has a central winding leg 23 and yoke sections 24,
25 which are firmly held in assembled relation with the
central leg 23 by the clamping elements 26, 27. Primary
winding P and cathode heating windings H1, H2 are in
cluded in coil assembly 28. Coil assembly 29 which in
cludes the secondary winding S is disposed on the central
winding leg 23 alongside of and spaced from coil assem
bly 2S.
Ballast apparatus 1% is housed in an elongated conduc
mary winding P1, a secondary winding S1 inductively cou
pled therewith on magnetic core 61, cathode heating wind
ings H1, H2, H3 and magnetic shunts 62. A pair of input
terminal leads 63, 64 are connected across primary wind
ing P1 and are provided for connection to a suitable alter
50
nating current supply shown schematically by the dashed
lines 65, 66, the low potential side of the power supply
line 65 being identi?ed by the ground connection 52.
30, only portions of which are shown. The capacitor 13
Cathode heating winding H3 is connected in circuit with
and container 9 are disposed at the other end of the ballast
case 11 and container 9 is connected to the ballast case 11 55 the cathodes 67, 68 by leads 69, 7t) and cathode heating
windings H1, H2 are connected in circuit with cathodes
by lead 31. As shown in FIG. 2, one end of the lead 31
71, 75 by leads 613, '72 and 59, 73, 74, respectively. Cath
is attached to the capacitor container 9 by some suitable
ode heating winding H1 is an extension winding of primary
attaching means such as solder and at the other end it is
winding P1 and cathode heating windings H2, H3 are tight
attached to an eyelet portion 32. When the cover plate
30 is assembled with ballast case 11, the lead 31 is engaged 60 ly coupled with the primary winding P1 and may, if de
sired, be wound directly over the primary winding P1.
between eyelet portion 32 and the cover plate 30. Since
The reactive impedance between capacitors 56, 58 and
the ballast case 11 is generally secured to a lamp ?xture,
container 57 and the outer foils of capacitors 56, 58 is
which is shown schematically in the circuit diagram of
represented schematically by a capacitor 76 and connec
PEG. 1, as the conductive plate 18 connected to a ground
33, the ballast case is also substantially at ground poten 65 tions 77, 78 shown in dashed lines. Thus, in the exempli
?cation of the invention shown in FIG. 3, the starting
tial as shown by the connection of ballast case 11 to
capacitor 53 and the power factor capacitor 56 are pref
ground in FIG. 1.
erably contained within the same metal container 57, and
As shown in FIG. 1, the capacitor container 9 is repre
the container 57 is connected by lead 83 to the ballast
sented schematically by the dashed rectangle 9 and is con
tive ballast case 11 which is covered with a cover plate
nected by lead 31 to the ballast case 11. The reactive im
pedance developed between the capacitor container 9 and
the capacitor outer foil of capacitor 13 is represented sche
matically in FIG. 1 by a capacitor 35 and connections 36,
37 shown in dashed lines. In effect, by connecting the
capacitor container 9 to the grounded ballast case 11 or
case 51, which is connected to a ground 47.
As shown in FIG. 4, capacitors 56, 58 are contained in
a single container 57 provided with three terminals 80, 81,
82. The capacitor container 57 is connected in electrical
circuit with the ballast case 51 by lead 83, which is at
tached to the ballast case 51 by solder at one end and at
3,089,980
5
6
the other‘ end is connected to an eyelet 84. When cover
plate 85 of the ballast case is attached, the end of lead 83
at the eyelet 84 is brought in good electrical contact with
the immediate vicinity of cathode 16. The current ?ow
in the auxiliary starting aid circuit follows a path from
the cathode 16 to the capacitively coupled conductive
the ballast case 51.
plate 13, ground 33, lead 31, capacitor container 9, to
‘Continuing with the description of the components
of the ballast apparatus Ell, as they are shown in MG. 4,
it will be seen that cathode heating windings H1, H2,
H3 and the primary winding P1 are included in coil
secondary winding S, output lead 14 and to cathode 16.
Thus, the lead 31 connected to capacitor container 9
solely provides a current path for the auxiliary starting
assembly 85 mounted on a central winding leg 86. Sec
tively high impedance presented by the capacitive re
aid current to the ballast apparatus.
Due to the rela
ondary winding S1 is included in coil assembly 87 ar
ranged on winding leg 86 adjacent to the coil assembly
81*? and separated therefrom by shunts 62. The shunts
62 provide a leakage path in the magnetic core 61 be
actance between the capacitor container 9 and the outer
foil of the capacitor 13 and the high capacitive reactance
between lamp L and the conductive plate 18, only an
insigni?cant current in the order of a few microamperes
tween the primary winding P1 and the secondary wind
will flow in this circuit. However, this current is sul?
ing S1. It will be noted that the magnetic core 61 has 15 cient to substantially increase the ionization of the gas
a pair of yoke sections 88, 39 which are held in as—
in the vicinity of the cathode 16 and in conjunction with
sembled relation with the central winding leg 86 by
clamping elements $4), 91 so that a closed magnetic cir
cuit is formed.
the voltage applied by the secondary winding S at the
output leads 14, 15 causes lamp L to start.
‘When the lamp has started, the starting aid circuit
The capacitors employed in the ballast apparatus of 20 is substantially ineffective in the operating circuit and
the invention are conventional static capacitors having
liquid or solid dielectrics and a capacitor roll with in~
terleaved sheets of paper and metallic foil, the roll and
the dielectric being sealed in a metal container. Since
any current ?ow in this circuit is insigni?cantly small
as compared with the current ?owing through the lamp L.
In the operation of the ballast apparatus 50 shown
in FIG. 3, input terminal leads 63, 64 are connected
the metal container is separated from the outer metallic 25 across supply lines 65, 66 energized from a suitable
foil by the dielectric within the container, a capacitance
supply of alternating current such as a 120 volt, 60
exists between the container and the outer metallic foil
cycle commercial supply. Voltages are immediately in
of the capacitor roll.v The amount of this capacitance
duced in the cathode heating windings H1, H2, H3, and
is a function of the area of the two surfaces, the spac
a cathode heating current is supplied to the cathodes 67,
ing between the surfaces and the properties of the 30 68, 71, 75 of lamps L1 and L2. Also, the open circuit
dielectric. I have discovered that the capacitance be
voltage developed across the primary winding P1 and
tween the outer foil and the metal container is of sul?
the secondary winding S1 of the ballast transformer 55
cient magnitude in static capacitors normally used in
is applied across lamp L1, the turns ratio of the trans
ballasts and this capacitance can be eifectively utilized
former 55 being such that the open circuit voltage is of
in the starting aid circuit by connecting the container 35 su?icient magnitude to initially start lamp L1. At the
to ground.
same time, the auxiliary starting aid circuit applies the
Referring now to FIG. 5, I have illustrated a conven
voltages across primary winding P1 and secondary wind
tional capacitor assembly 93 constructed in the usual
ing S1 to cathode 71 of lamp L1 which is in capacitive
manner. As is shown in ‘FIG. 5, the assembly 93 is
relation with the conductive plate or ?xture. A return
constructed of a capacitor roll 94 comprised of metallic 40 ground with the conductive plate 48 is completed through
ground 49 to either the ground 47 to which capacitor
foils 95, 96, such as aluminum, in which metallic foils
are interleaved with sheets of paper 97, 98 to form foil
container 57 is connected or the ground of the low
layers 95, 96 separated substantially only by the paper
potential line 65.
layers.
After lamp L1 has started, the voltage across the
As shown schematically in FIG. 1, the upper and 45 starting capacitor 58 is applied across lamp L2. Lamp
lower plates of the capacitor correspond to the foil
L2 also being in close proximity to the conductive plate
layers 95, 96, respectively. Tap straps 99, 160 are
48 has an ionization potential applied to cathode 67 by
brought out from the foil layers d5, 96 and connected
the auxiliary starting aid circuit. The gas in the vicinity
to the outer terminals 101, 102. The wound assembly
of the cathode 67 will ionize causing lamp L2 to be
of foil layers 95, 96 and paper dielectric spacers 97, 98
come conductive and the open circuit voltage between
are placed in a metal container 163 having a cover
1% arranged thereon so as to hermetically seal the
tained within lamp L2 thereby igniting lamp L2. The
capacitor roll 94 and dielectric material 195. Because
of the spacing which necessarily exists between the outer
starting capacitor 58 has sul?cient impedance so that
no appreciable operating current will ?ow through it
cathodes 67, '75 causes a breakdown of the gas con
foil layer 96 and capacitor container 103, the capacitance 55 when both lamps L1 and L2 are ignited.
exists between these two metallic surfaces since they are
Lamps L1
and L2 are operated in a series circuit relationship across
separated by dielectric material M5. As previously men
the primary winding P1 and the secondary winding S1
tioned, the amount of capacitance depends upon the
of the ballast transformer 55. After the lamps L1 and
area of the surfaces, the spacing and the type of dielec
L2 are ignited, only a negligible amount of current will
tric material used. In accordance with the invention, 60 flow from the lamp cathodes to the conducting ?xture
this capacitance is utilized to solely provide the im
because of the high impedance of the capacitive coupling
pedance that is required in the starting aid circuit in
between lamps L1, L2 and the conductive plate 48.
FIGS. 1 and 3.
In order to demonstrate the advantages of the present
The operation of the circuit shown in ‘FIG. 1 will now
invention, the ballast apparatus Stl shown in FIG. 3 was
be more fully explained. When a voltage is applied 65 constructed and tested by operating a pair of 40 watt
to the input terminal leads 21, 22 of primary winding
?uorescent lamps from a 120 volt, 60 cycle alternating
P, a voltage will be induced in the secondary winding S
current supply. The high reactance ballast transformer
as determined by the respective turns ratio of the primary
55 was designed to provide a minimum open circuit
winding P and secondary winding S. The voltage across
voltage of 280 volts across the output leads 59 and 60.
the secondary winding S is applied across lamp L by 70 A power factor capacitor 56 having a rating of 4 micro
means of the output leads 14, 15 connected in circuit
thereto. Further, the cathodes 16 and 17 are simul
taneously supplied a heating current by cathode heat
ing windings H1, H2, respectively. Also, the auxiliary
starting aid circuit causes a potential to be applied in
farads at 300 volts AC. and a starting capacitor 58
having a rating of .05 microfarad was used. The ca
pacitor container 57 was grounded to the ballast case 51.
During the measurements of the starting aid potential,
the primary operating voltage was maintained at 108 volts
8,089,980
0
(.2
7
What I claim as newv and; desire to secure by Letters
Patent of the United States is:
or at minus 10 percent of the rated operating voltage in
accordance with standard procedure. The starting aid
1. A ballast apparatus for starting and operating at
voltage measurements were taken with a Rawson peak
least one fluorescent lamp disposed in a capacitive rela
tion with a conductive ?xture, said apparatus comprising
a high reactance transformer having a primary winding
recti?er and a Rawson electrostatic voltmeter. The start
ing aid potential was measured by reading the voltage
between the ballast case 51 and the output lead 60. For
the circuit shown in FIG. 3, the starting aid voltage or
and a secondary winding inductively coupled therewith
potential between cathode '71 and the ballast case 51 was
On a magnetic core, a pair of input terminal leads con
nected across said primary winding, a circuit means in
found to be approximately 360 volts when the conduc
tive plate or ?xture 48 was not grounded.
10 cluding a pair of output leads for applying the output of
By way of comparison, similar starting aid voltage
said transformer across said lamp, a capacitor serially
connected with said secondary winding to cause a leading
current to iiow therethrough, a conductive ballast case,
as shown in FIG. 3 wherein a conventional grounding re
said high reactance transformer and capacitor being dis
sistor was connected in circuit with the low potential end
of the primary P, and the ballast case 51. With a starting 15 posed in said ballast case, said capacitor including a
measurements were taken for an identical ballast circuit
capacitor roll having electrodes of interleaved foil layers
resistor and capacitor container in the circuit grounded,
and a conductive container for housing said capacitor and
the starting aid voltage corresponding to a voltage of 108
disposed in capacitive relation with the outer foil layer
volts across the primary winding was ‘found to be 280
and circuit means for connecting said container in elec
volts. Also, with the starting aid resistor installed but
with the capacitor container ungrounded, it was deter 20 trical circuit relationship with said ballast case, the
capacitance between said container and said outer foil
mined that the measured starting aid voltage was approxi
layer providing su?icient impedance during operation to
mately 278 volts. Thus, it will be seen that by grounding
prevent any signi?cant current flow from the apparatus
the capacitor container and by eiminating hte grounding
to said ballast case and said circuit means for connecting
resistor an increase of approximately 28.5 percent is ob
25 said container providing the only return path within said
tained in the starting aid potential.
ballast case for the auxiliary starting aid current.
Where the ?xture 4-8 was grounded as shown in FIG.
2. The ballast apparatus set forth in claim 1 wherein
3, the starting aid voltage was measured at 304 volts with
said secondary winding is connected in isolated trans
the capacitor container 51 grounded and without a start
former relationship with said primary winding.
ing aid resistor. By way of comparison, the ballast ap
3. Ballast apparatus for starting and operating a gas
paratus with a starting aid resistor connected to the low 30
eons discharge lamp from a source of alternating current,
potential end of the primary P, and with the capacitor con
said lamp being mounted in a conductive ?xture and dis
tainer ungrounded was tested. The starting aid voltage
posed in capacitive relationship therewith, said apparatus
was measured at 260 volts. Further, with the starting aid
comprising: a high reactance transformer having a. pri
resistor in the circuit and the capacitor container
mary winding and a secondary winding inductively cou
grounded, the starting aid voltage was measured at 262
pled therewith on a magnetic core and a pair of input
volts.
leads for connection across the alternating current source;
Preferably, it was found that the capacitance between
a power factor capacitor connected in series circuit rela
the capacitor container 57 and the outer foil of the
tionship ‘with said secondary winding to cause a leading
capacitor should not be less than 880 picofarads. It was
found that when the ballast apparatus 59‘ shown in FIG. 40 current to flow therethrough, a ballast case, said power
‘factor capacitor and said high reactance transformer
3 was operated from an ungrounded power supply and
being housed in said ballast case, said capacitor in
with the capacitor container 57 grounded that the auxiliary
cluding a capacitor roll and a metallic container pro
starting aid voltage began to decrease below 880 pico
\farads. The capacitor container ‘57 of capacitors 56, 5%
viding an enclosure ‘for at least said power factor
used in the circuit provided a capacitance between the
container 57 ‘and the outer foil of capacitors 56, 58' of
capacitor, circuit means connecting said container in
electrical circuit relationship with the ballast case, said
circuit means providing the only return path for the
auxiliary starting aid current when said alternating cur
approximately 1700 picofarads. However, where the
circuit was operated with a normally grounded supply, it
rent source is not grounded, the capacitive reactance be
was noted that variations in the capacitance between the
outer foil and container 57 did not have an appreciable 50 tween said capacitor roll and said container providing
suf?cient impedance to prevent any signi?cant current
effect on the starting aid potential.
?ow ‘from the apparatus to the ballast case thereby elimi
From the foregoing description, it will be apparent that
nating the need for a grounding resistor, and circuit means
the auxiliary starting circuit arrangement of the present
including electrical leads for connection across said lamp
invention not only provides a signi?cant improvement in
the auxiliary starting aid voltage, but also eliminates the 55 to apply the output of said high reactance transformer
need for a grounding resistor.
It will be understood that while I have illustrated my
across said lamp.
invention by speci?c embodiments thereof, the invention
has general applicability to ballast circuits which utilize
least one ?uorescent lamp from an alternating current
4. A ballast apparatus for starting and operating at
supply, said lamp being disposed in a capacitive relation
an auxiliary starting circuit to aid in the starting of the 60 with a conductive plate, said apparatus comprising: a high
reactance transformer having a primary winding and a
?uorescent lamps. Thus, the invention may be employed
secondary winding inductively coupled therewith on a
in ballast circuits used to start and operate rapid start
magnetic core, a pair of input terminal leads connected
and instant start lamps. It will also be apparent to‘ those
across the primary winding for connection to the alter
skilled in the art that the auxiliary starting circuit arrange
ment in accordance wiht the invention can be employed 65 nating current supply, a capacitor connected in series cir
cuit relationship with said secondary winding to cause
in many other ballast circuit con?gurations other than
a leading current to ?ow therethrough, a ballast case
those which have been illustrated herein by way of exem
pli?cation of the invention. While the present invention
has been described by reference to speci?c exempli?ca
tions thereof, it is to be understood that modi?cations may
be made by those skilled in the art without actually de
parting ‘from the invention. It is, therefore, intended in
the appended claims to cover all such equivalent varia
tions that fall within the true spirit and scope of the
75
invention.
for housing said apparatus, said capacitor having a metal
lic container and a capacitor roll, said container being
spaced from said roll and disposed in capacitive relation
therewith and circuit means connecting said metallic con
tainer in electrical circuit relation with said ballast case
and forming a low potential connection in the starting
aid circuit, said capacitive reactance between said capacitor
container and said roll providing sufficient reactive im~
3,089,980
10
pedance to prevent any signi?cant current flow to said
ballast case, and said circuit means providing the only
return path for the auxiliary starting aid current when
housing said apparatus, a starting capacitor, circuit means
including electrical leads for connecting the output of
said alternating current supply is not effectively grounded.
5. A ballast apparatus for starting and operating a
gaseous discharge lamp from an alternating current supply,
said lamp being mounted in a conductive ?xture and dis
nected lamps and for connecting said starting capacitor
said high reactance transformer across said serially con
across one of said lamps, at least one of said capacitors
having a metallic container and a capacitor roll having
posed in capacitive relationship therewith, said apparatus
interleaved foil layers and dielectric layers disposed there
in, the outer foil layer of said capacitor roll being spaced
comprising: a ballast transformer having a primary wind
from said metallic container and in capacitive relation
ing and a secondary winding inductively coupled there 10 therewith, grounding circuit means connecting said metal
with on a magnetic core, said secondary winding being
in isolated transformer relationship with said primary
winding, a pair of input leads for connection across the
alternating current supply, said primary winding being
connected across said input terminal leads, a capacitor
connected in series circuit relationship with said second
lic container in electrical circuit relation with said ballast
case to provide a grounded connection for the ballast ap
paratus, the capacitive reactance between said capacitor
container and the outer foil layer providing su?icient im
pedance to prevent any signi?cant current ?ow from the
high reactance transformer to said ballast case during
foil layers and dielectric layers, said roll being disposed in
said metallic container, said metallic container being
spaced from said roll and capacitively coupled with the
operation and said grounding circuit means providing the
only return path for auxiliary starting aid current from
said conductive plate.
8. A ?uorescent lamp lighting system comprising at
least one ?uorescent lamp, a conductive plate, said lamp
being disposed in capacitive relation with said conductive
outer foil layer of said roll and circuit means connect
plate so that an auxiliary starting aid current can ?ow
ary winding to cause a leading current to ?ow thereto, a
ballast case for housing said apparatus, said capacitor
having a metallic container and a capacitor roll formed of
thereto, a high reactance transformer having a primary
ing said metallic container in electric circuit relation with
said ballast case in order to provide a grounded connec 25 and a secondary winding inductively coupled therewith on
a magnetic core, a pair of input terminal leads connected
tion for the ballast apparatus in a starting aid circuit, said
across said primary winding, circuit means including elec
capacitive reactance between said capacitor container and
trical leads for connecting the output of said high react
said outer foil layer providing su?icient reactive imped
ance transformer across said lamp, a capacitor serially
ance to prevent any signi?cant current ?ow from said
ballast transformer to said ballast case and said circuit 30 connected with said secondary winding to cause leading
means providing the only return path for the auxiliary
starting aid current from the conductive ?xture.
6. A ballast apparatus for starting and operating a pair
of ?uorescent lamps from an alternating current supply,
said lamps being disposed in capacitive relation with a 35
current to ?ow in said secondary winding, said capacitor
including a capacitor roll having interleaved foil layers
and dielectric layers and a metallic container disposed in
capacitive relation with at least the outer foil layer of
said roll, a ballast case for housing said apparatus, ground
ing circuit means connecting said capacitor container in
conductive plate so that .an auxiliary starting aid current
electrical circuit relation with a ballast case for providing
can ?ow thereto, said apparatus comprising: a high re
a grounded connection to form a starting aid circuit with
actance transformer having a primary winding and a
said conductive plate, said capacitive reactance between
secondary winding inductively coupled therewith on a
magnetic core, a pair of input terminal leads connected 40 said outer foil layer of said capacitor roll and said con
tainer providing su?icient impedance to prevent any sig
across the primary winding for connection to the alternat
ing current supply, a power factor capacitor connected in
ni?cant current ?ow from said high reactance transformer
to said ballast case during operation, and said grounding
series circuit relationship with said secondary winding to
cause a leading current to ?ow therethrough, a starting
circuit means providing the only return path for the aux
capacitor, circuit means including electrical leads for con
iliary starting aid current from said conductive plate to
necting the output of said high reactance transformer 45 said ballast apparatus.
across said ?uorescent lamps and for connecting said
9. A ?uorescent lamp lighting system comprising a pair
starting capacitor across one of said lamps, said power
of ?uorescent lamps, a conductive plate, said lamps being
factor capacitor and said starting capacitor being enclosed
disposed in capacitive relation with said conductive plate
in a metallic container and having a capacitor roll formed
so that a starting aid current can ?ow thereto, said con
of interleaved foil layers and dielectric layers disposed in 50 ductive plate being grounded, a high reactance trans
said container, and grounding circuit means connecting
former having a primary winding and a secondary wind
said metallic container in electrical circuit relation with
said ballast case in order to provide a grounded connec
ing inductively coupled therewith on a magnetic core, a
tion for the ballast apparatus in the auxiliary starting aid 55 pair of input terminal leads connected across said primary
winding and provided for connection across an alternat
circuit, said capacitive reactance between said metallic
ing current supply, a capacitor connected in series cir
container and the outer foil layer of said roll providing
cuit relationship with said secondary winding to cause
su?icient impedance to prevent any signi?cant current ?ow
from said ballast apparatus to said ballast case and said
a leading current to ?ow therethrough, a starting capac
itor, a ballast case for housing the ballast apparatus, cir
grounding circuit means providing the only return path
for the auxiliary starting aid current from the conductive 60 cuit means including electrical leads for applying at least
the voltage across said secondary winding across said
plate to the ballast apparatus.
lamps and for connecting said starting capacitor across
7. A ballast apparatus for starting and operating a
one of said lamps, said starting capacitor and power fac
pair of serially connected ?uorescent lamps from an alter
nating current supply, said lamps being disposed in ca
tor capacitor having a metallic container and a capacitor
65
pacitive relation with a conductive plate so that an aux
roll formed of interleaved foil layers and dielectric layers,
iliary starting aid current can ?ow therethrough, said
the outer foil layer of said capacitor roll being disposed
apparatus comprising: a high reactance transformer hav
in capacitive relation with said metallic container, the
ing a primary winding and a secondary winding induc
reactive capacitance between said container and said
tively coupled therewith on a magnetic core, a pair of in 70 capacitor roll providing su?icient impedance during op
put terminal leads for connection to the alternating cur
eration to prevent any signi?cant current ?ow from the
rent source, said primary winding being connected across
high reactance transformer to said ballast case, ground
ing circuit means connecting said metallic container to
said input terminal leads, a capacitor connected in series
said ballast case for providing a grounded connection,
circuit relationship with said secondary winding to pro
vide a leading current therethrough, a ballast case for 75 said grounding circuit means providing the only return
3,089,980
11
12
path for the auxiliary starting aid current when said pow
limiting impedance is provided for said lamp, a conduc
er supply is not grounded.
tive ballast case for housing said apparatus and arranged
for connection to said conductive plate, and circuit means
10. A‘ballast apparatus for starting and operating from
an alternating current supply at least one gaseous dis
charge lamp disposed in a capacitive relation with a
grounded conductive plate, said apparatus comprising
a pair of input terminal leads for connection With the
connecting said container in electrical circuit with said
ballast case, said capacitance providing sufficient im
pedance during operation to prevent any signi?cant cur
rent ?ow from the apparatus to said ballast case and
alternating current supply, a ballast means, a capacitor,
said capacitor having a capacitor roll and a conductive
said last mentioned circuit means providing the sole path
within said ballast case for auxiliary starting aid current
container disposed in capacitive relation with said roll 10 to said conductive plate and lamp.
to provide a capacitance therebetWeen, circuit means in
cluding electrical leads for connection With said lamp,
said circuit means connecting said input terminal leads,
said ballast means and said capacitor in circuit with said
electrical leads for connection with said lamps so that
a leading current is supplied to said lamp and a current
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,802,143
Kobayashi ___________ __ Aug. 6, 1957
2,960,624
Strecker ____________ __ Nov. 15, 1960
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