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Патент USA US2410052

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Oct. 29, '1946.
L. F. BEACH
2,410,039
MAGNETIC FIELD ,RESPONSIVE DEVICE
Filed July 31, 1941
‘
\COMMUTATOR
2 Sheets-Sheet l
>
AMPLIFIER
TO
OR
INDICATOR
CONTROL
INVENTOR
‘
,
CIRCUIT
LENNOX F‘ BEACH -
HIS.
ATTORNE
.
Oct. 29, 1946.
L. F. BEACH
'
2,410,039
MAGNETIC FIELD RESPONSIVE DEVICE
Filed July 51, 1941
2 Sheets-Sheet 2
‘FIE-.5
H 5.53
MOTOR
2-POLE
v
ALTERNATO
' /
843
4-—POLE
ALTERNATOR
INVENTORS
LENNOX
F. BEACH ,
Patented Oct. 29, 1946
2,410,039
UNITED STATES PATENT‘ OFFICE
MAGNETIC FIELD‘ RESPONSIVE DEVICE
Lennox F. Beach, Merrick, N. Y., assignor to The
Purves Corporation, Spring?eld, Mass, a cor
poration of Massachusetts
Application July 31, 1941, Serial No. 404,809
13 Claims. (Cl. 175-183)
1
2
This invention relates to magnetic ?eld‘ re
The primary windings may be energized by any
periodically varying current and arev illustrated?
as being energized by alternating current from]
secondary winding i3 of power transformer T5
sponsive devices, especially of the type‘ shown‘ in
Patent No.'2,047,609, issued July 14, 1936, to Haig
Antranikian. As‘ therein explained, such devices
operate on the principle of a- magnetic core whose
reluctance is periodically varied by a periodically
varying energizing magnetomotive force and
which will respond to ?xed or varying external
magnetomotive forces to yield.- a periodic output
current or voltage whose phase‘ will correspond
to the polarity or direction of the external mag
netomotive force, and whose magnitude will cor
respond to the instantaneous intensity ‘of the
whose primary i7 is connected to any suitable
source of alternating current. It is to- be under
stood that the terminals of winding 5‘, 1 may be
connected to’ any source of periodically varying
voltage. Secondary II‘ and primaries 5', ‘I are $0
arranged that, in the absence of any‘ external’ .
magnetic ?eld components along core 3 (aswherr
the core points East and West if the earth’s magi-i
netic ?eld is used‘), no voltage is induced in sec->
onclary M. This adjustment may be‘ performed’
The present invention is concerned with im 15 by making coil ll slidable along 0011's 5, 1,
provements on the type of device shown in the
A suitable construction‘ for this‘ pick-up device
above patent, and‘ adaptations of this improved
is shown in my copending application Serial No.
device to uses such as magnetic ?eld direction
348,582 for Direction indicator for magnetic
magnetomotive force.
.
and/or sense indicators, magnetic ?eld intensity
?elds, ?led July 30; 1940, and which matured-on
indicators, and magnetic ?eld responsive de 20 August 28, 1945- into U. S. Patent No. 2,383,459.
vices.
Alternatively, core l maybe formed in two sep
It is accordingly an object of the present in~
vention to provide an’ improved‘ indicator for the
direction and/or sense of a magnetic ?eld such
arate but adjacent sections, each section having
as the earth's ?eld.
being, series-connected, to provide a voltage
thereacross which is produced through interac
It is another object of this invention to pro
vide an improved device for determining the in
stantaneous intensity of a ?xed or varying mag
netic
?eld.
‘
'
a primary‘ winding such as 5 or 1 and half of the
secondary winding» H, the two secondary halves
tion between the device and the external ?eld,
the primary windings being preferably series
connected.
It is a further object of this invention to pro 30
One terminal !2 of secondary H’ is connected
vide an improved relay device responsive to a
to one side of direct zero-center meter l9 whose
magnetic ?eld.
Other objects and advantages will; become ap
parent from the speci?cation, taken in connec
tion with. the accompanying drawings wherein
the invention is embodied in concrete form.
In the drawings,
Figs. 1 to 3 are schematic diagrams of devices
for indicating the direction and intensity of
magnetic ?elds;
Fig. 4 is‘a schematic diagram of a relay device
responsive to magnetic ?elds;
other terminal is connected to the junction 22
of two series connected recti?ers 2|. These rec
ti?ers may be of any desired type, such as chem
ical, electrical, etc. The recti?ers 2'! are con:
nected in series across another secondary’ 23. of
supplytransformer [5. When a different source
of periodically varying voltage is used, the ter-.
minals of recti?ers 2! may be connected directly.
thereacross.
.
.
Also connected across this secondary23 is a
potentiometer resistor 25,. whose variable arm 2.‘!
is connected to the other terminal ll! of pick-up
of Figs. 1 to‘ 3; and,
._
secondary ll. Arm 21 is adjusted so that its. po
Fig. '7 is. a schematic diagram, of‘ a. magnetic 45 tential is the same asthat of the junction 22 of
‘Figs. 5.and‘6 are modi?cations of the devices.
?eld intensity measuring device.
Fig. 1 shows a device for indicating the orien
recti?ers 2!-
“
tation and instantaneous intensity of a ?xed or
When. core, 3 is unaffected by external mag
netic ?elds, it will be symmerically and periodi
varying magnetic ?eld. A magnetic pick-up de
cally magnetized in opposite directions by the
vice i has a core'3 upon which are wound iden 50 alternating current in the primary windings: 5;
‘l, the current magnitude being adjusted to op
tical primary coils 5, ‘I. These coils are con
erate the core with varying permeability andre
nected in series, as at 9, and are wound so as to
luctance. If the core is subjected to an external
create opposing magnetomotive forces and ?uxes
in core 3., Also, wound on core 3- and' preferably
concentric9 with coils 5, ‘I is‘ a, secondary coil ll.
magnetic ?eld. for instance the earth’sv ?eld,
then, as the primary current passes through zero‘,
2,410,039
4
there will be a time displacement of the point of
zero magnetism. There will be a resulting time
interval between the instants that the right and
external magnetic ?eld (right or left) with re
spect to the axis of core 3. Since the intensity of
the external ?eld determines the Voltage picked
left portions of the core pass through zero mag
netism. This time interval will increase as the
up by secondary II, meter I9 may be calibrated
in magnetic ?eld units to read directly the in
tensity and polarity of the component of the ex
strength of the external ?eld is increased.
This e?ect produces an alternating voltage in
the secondary winding II having a component of
ternal magnetic ?eld along the axis of core 3.
If the only external ?eld is the earth’s ?eld, this
device will indicate the component of the earth’s
double the frequency of the "primary current.
Reversal of the direction of the external magnetic 10 ?eld along the axis of core 3. Meter I9 maybe
calibrated directly in degrees of magnetic bear
?eld will produce phase reversal of the secondary
voltage.
V
ing, permitting the use of the device as a magnetic
»
In other words, the exciting coils 5 and ‘I, when
compass.
'
Itis found that the absolute magnitude of the
energized from a suitable source of alternating '
output voltage from secondary winding II de
pends upon the relative phase of the current in
,the primary coils with respect to the voltage
or pulsating current, will produce periodically
varying ?uxes in the core 3 of permeable mag
netic material. ' The number of ampere turns
will determine the degree of saturation produced
across recti?ers 2I. A condenser 29 is therefore
used to adjust this phase relation to an optimum
along its magnetization curve. Therefore, the 20 value. This condenser may be variable, and is ad
amount of current supplied to these exciting
justed by noting maximum indication on meter
windings or coils having a given number of turns
I9 for a given external ?eld.
.
will determine the desired degree of saturation
It is not necessary to use center~tapped re
of the core. The periodically varying ?uxes pro
sistor 25. The connection to point 2‘! may be
duced in the core by the coils 5 and ‘i will be in 25 made directly to a center-tap on secondary wind
bucking relationship due to the arrangement of
ing 23. Also, the two separate secondary wind
these coils and if the secondary or pick-up wind
ings 23 and I3 may be combined‘into one, with
ing “is properly adjusted in symmetrical rela
the energizing circuit for coils 5, ‘I and the recti
tion to these ?uxes, no voltage of fundamental
fier circuit connected in parallel thereto. Fur
frequency or of the frequency of the source of en 30 thermore, the present connection to point 21 may
ergy used in exciting the core will appear in the
be made to the junction 9 of coils 5 and ‘I, thereby
in the core or the zone of operation of the core
pick-up winding. In this invention, it will be ob
served that the coil Il may be adjustedaxially
reducing the number of wires to the pick-up unit
I, which may be, and usually is, located at a dis
of the core 3 to effectively balance out this funda
tance from the indicator meter I9.
'
mental frequency voltage. However, when the 35
Fig. 2 shows a modi?cation of the device of
core is subjected to an external unidirectional
Fig. 1. Here the pick-up unit primary windings
?eld, unidirectional fluxes are induced in the core
5, ‘I are energized from a two-pole alternator 2V9
, 3 thereby rendering the wave form of the voltage
driven at constant speed by motor 3!. Switching
induced in let us say one Pick~up winding of an
is effected by commutator 33, which has two ?xed
unsymmetrical character. This is due to the fact 40 90° segments 35, 31 and a movable shorting arm
that a double frequency component is present
in the induced voltage and it is the double fre
quency component, the fundamental being
bucked out, which is supplied to the indicating
39 rotated by motor 3| in synchronism with al
ternator 29. Arm 39 connects segments 35, 31
for 90 degrees of rotation of alternator 29, opens
the circuit for the succeeding 90 degrees, and re
means as a measure of the strength of the uni 4: peats this cycle. Since alternator 29 will gen
directional ?eld along the longitudinal axis of
erate one cycle per revolution, commutator 33,
the core.
'
which isconnected in series with secondary wind
Meter I9 is of the direct current zero-center
ing II and zero center meter I9, will close the sec
type and is used to indicate the direction and in
ondary circuit for alternate quarter cycles orthe
tensity of the external ?eld. For this purpose,
primary current, which correspond to alternate
recti?ers 2| are used to block off the current of
half-cycles of secondary current, which has a
secondary winding I I during half-cycles of the
frequency double that of the primary current.
supply voltage fed from winding 23 having a
By properly phasing the commutating action with
given polarity and to permit passage of second
respect to the alternator voltage output, as by
ary current only during the half-cycles of op
shifting arm 39 relative to shaft 43, the commu
posite polarity.
' tator 33 is adjusted to effect mechanical recti
Thus, let it be assumed that recti?ers 2| will
conduct only when their upper terminals are posi
tive with respect to their lower terminals. Dur
ing the half-cycle of voltage from supply second
?cation of the secondary current, and direct cur
rent meter I9 will indicate the sense of the devi
ation of the coil axis from the axis of the external
?eld, by its right or left de?ection, and the
amount of such deviation, by the amount of de
ary 23 that these recti?ers are conducting, a cur
rent from secondary II will flow through meter
?ection.
.
-
'
'
I9 and through one or the other of the recti?ers,
depending on the polarity of this current from
winding I I. It will produce de?ection of the in
dicator of meter I9 in a direction corresponding
It is obvious that the primary coils 5, ‘I "of Fig.
2 might as well be energized from any source of
periodically varying current, so long as the com
mutator 33 is properly synchronized with the fre
to its polarity. During the succeeding half-cycle
of supply voltage from Winding 23, both recti
quency of the source, so as to provide proper in
?ers .2I are'maintained non-conductive by the
voltage of winding 23, since this voltage is much
larger than the voltage across secondary winding
I I, so that no current can ?ow through the meter
I9. The meter I9 is thereby supplied with cur
rent of predominantly one polarity and that po
the secondary current.
Fig. 3 shows a pulsating current supplied to
primary windings 5, ‘I by means of vibrator 45
having coil 4'! and armature 49. Current from
battery 55 energizes coil 41 and draws up arma
larity corresponds to the relative direction of the
terruption and phase-sensitive recti?cation of
'70
ture 49 against the opposition of spring 51. Con
tacts 5| are thereby closed and short circuit coil
2,410,039
5
6
41, permitting spring 51 to withdraw armature 49,
and open contacts 5|, whereupon the cycle of
operations is repeated.
the anodes energized directly from secondary‘ 23
of supply transformer ‘I5. A center-tapped choke
coil may be used in place of resistor ‘II. A suit
Contacts 53 are opened and closed‘ in syn
' able bias may be inserted‘between the cathodes
chronism with the operation of armature A9,. and
oftube 69‘ and the center-tap of resistor ‘II, or its
choke equivalent if it is desired to make the de
serve to open or close the circuit of meter lBg.
The pulsating current supplied to primary
, vice. responsive only above a predetermined sig
coils 5, ‘I creates a double frequency current in
nal level.
v
_
I
secondary I I, in the presence of an external mag»
Fig. 6 shows another modi?cation of the device
netic ?eld, as in Figs. 1 and 2. The secondary 10 in which all Switching means are eliminated.
current is connected. to meter I9, in series with
Motor 3! drives two-pole. alternator 29 and four
interrupter contacts, 53, an ampli?er 59 being, in
pole alternator I253. The voltage generated by the
serted if necessary.
two-pole alternator energizes primary windings
»
The phase of the primary current pulsations
5, ‘I. The double frequency output from second
relative to. the interruption of contacts 5i is ad 15 ary coil I I is fed to one coil, for example the mov
justed‘by adjustingv the capacitance of condenser
ing coil 19, of dynamometer-type meter 8 I, whose
BI, to yield maximum secondary current for ?xed
second, or ?xed winding 83 is energized from the
double frequency output of four-pole alternator
external ?eld. Once adjusted, condenser 6| re
I29. Meter 8i will indicate the relative magni
mains ?xed in value. Condenser 63 minimizes
sparking at contacts 53.
20 tude of the output voltages from alternator I29
Meter I9 will then give right or left indications
and secondary winding II. Also, the meter indi
according to the sense of the external ?eld, and
in amount according to the'intensity of the ex
ternal ?eld component along the axis of the coil.
Ampli?er 59 can be biased in known ways to pre
vent any output until a certain predetermined
input level is attained. In this way undesirable
two alternators is’ adjusted, either by adjusting
their relative ‘armature positions or by inserting
small random ?uctuations have no effect on meter
an adjustable condenser in circuit with one of
cation will reverse direction when the phase of
the voltage output from secondary winding VII
reverses.
'
1
,
, The phase relation between the outputs of the
them, to give a maximum de?ection on meter 8|
I9.
Fig. 4 shows a further modi?cation of the de 30 for ?xed position of the core 3 and ?xed magni
vices of Figs. 1 to 3, used as a magnetic ?eld in
tude of external ?eld.
Fig. 7‘ shows an adaptation of the special trans
dicator. In this ?gure, the output of secondary
winding I I_ is fed to an ampli?er 59, whose output
former of Figs. 1 to 6 for use as an instrument
for measuring the magneto-motive force and in
energizes the coil of relay 65. The contacts of
relay 65 may control any type of outside indica
tensity of an external ?eld. In addition to wind
ings 5, ‘i, ll on core 3, an additional winding 85
tor or control circuit. This device will respond
is placed symmetrically with respect to the re
to the approach or passage of iron or magnetic
maining windings. An adjustable amount of di
bodies, such as automobiles, trains, or parts on
a conveyor. The relay output may operate stop
rect current is passed through this winding 85
lights on a highway, or a counter.
from battery 53, the polarity and magnitude‘ of
The sensitiv- ,
ity of the device can readily be adjusted so as not
to respond to a disturbance below a certain ‘mini
mum value, and to record a strong signal as soon
as the disturbance exceeds this minimum, as by
proper bias on the input of ampli?er 59.
Fig. 5 shows a further modi?cation of Figs. 1
to 3. Here the voltage across the secondary wind
ing II may be tuned to double the supply ire~
quency as by condenser 6'1. The secondary wind
ing I I may be as tuned in any of the modi?cations
the current being adjusted by potentiometer 9|, _
and indicated on direct current meter 89. Coils
5, ‘I are provided with periodically varying cur
rent from source I‘! as in the other modi?cations.
CA
r.
of this invention. This secondary voltage is then
applied to the control grids of twin triode 69 by
way of center-tapped input resistor 'II whose cen
ter-tap is connected to the cathodes of tube 69.
The anodes of tube 69 are energized with pulsat
ing voltage from secondary winding 23 by way of
recti?er bridge '53 and equal load resistors 15.
Preferably, the double frequency, alternating
With zero direct current in coil '85, alternating
current meter ill will yield an indication of any
external ?eld. Potentiometer 9! is then adjusted
until meter 81 registers zero value. Then it will
be clear that the external ?eld is exactlyibal
anced by the ‘?eld produced by current in coil
85. Knowing the number of turns in coil 85, and
reading the current on meter, 89 will give im
mediately the magnetomotive force (ampere
turns) corresponding to the external ?eld. This
is also an indication of the external ?eld strength
and meter 88 may be calibrated. to read ?eld
strength at once. The polarity of current regis
tered by meter 89 will also indicate the direction
current ripple from the recti?er ‘i3 is used as the
of the external ?eld.
’
plate potential for the plates or anodes of tube
Of course, any of the indicating systems shown
G
O
in Figs. 1 to 6 may be used in place of meter 81.
69. Meter ‘I1 is connected across resistors '55, as
shown. With zero voltage input, both sections of
As many changes could be made in the above
tube 69 are adjusted to take equal plate current,
construction and many apparently widely differ
so that zero voltage will appear across meter 'i'i.
ent embodiments of this invention could be made
When secondary II produces voltage, it will act
without departing from the scope thereof, it is
differentially on the two sections of tube 69, re
intended that all matter contained in the above
sulting in a net voltage across meter ll, whose
description or shown in the accompanying draw
polarity depends on the phase of the input volt
ings shall be interpreted as illustrative, and not in
age from secondary winding I I. Tube 69 acts as a
a limiting sense.
,
'
'
phase discriminating device as well as an ampli
What is claimed is:
70
?er. The indication on meter 7'! will then indi
l. A device as in claim 9, in which said indi
cate both magnitude and direction of the external
?eld.
’
It is obvious that a duplex tube need not be
used, as two separate tubes would perform in the
same way. Also recti?er T3 may be omitted and 75
cating means includes an indicator and means for
rendering said indicator ineffective during alter
nate half-cycles of said periodically varying mag
netomotive forces.
‘
‘
-
2,410,039
7
8
2.‘ A device as in claim 9, in which said indicat
ing means includes an indicator, and means syn
is the mean of the potentials across ‘the energy
chronized with said varying magnetomotive forces
8. In a device sensitive to an external, unidirec
for rendering said indicator ineifective during
alternate half-cyles'of said varying magnetomo
tional magnetic ?eld for supplying a signal
voltage output dependent in magnitude uponthe
tive forces’.
3. .A magnetic ?eld responsive device compris
direction of said ?eld relative thereto, a‘ core of
permeable magnetic material, means including a
ing a core of magnetic, permeable material, means
including a source of periodically varying elec
source of periodically varying electrical energy
for producing periodically varying ?uxes in a
source for said recti?ers.
'
,
trical energy for producing periodically varying 10 zone of said core and in opposed bucking rela
?uxes in a zone of said core and in opposed buck
ing relationship, a pick-up coil associated with
tionship, a pick-up coil associated with said ‘core
in said zone thereof and positioned in symmetrical
said zone of the core and symmetrically positioned
with respect to said ?uxes, means for indicating
relation to said bucking ?uxes, interactionbe
tween said device and said external ?eld produc
the output from said coil, and phase-sensitive 15 ing a periodically varying voltage in, said pick-up
means connected with’said energy source for sup
plying a unidirectional current from said coil
output to said indicating means.
I
coil, and means forv rectifying ‘the output oflfsaid
coil, said rectifying means being connected .to
and controlled by said energy’ source whereby‘ to
4. A magnetic ?eld responsive device com
render the polarity sense of the recti?ed coiloute
prising a core of magnetic, permeable material, 20 put dependent upon the phase relationship of the
means including a source of periodically varying
coil output with respect to said energy source.‘
electrical energy for producing periodically vary
9. In a device sensitive to an external, unidirec'f
ing ?uxes in a zone of said core and in opposed
tional magnetic ?eld for supplying a signal voltage
bucking relationship, a pick-up coil associated
output dependent in magnitude upon the direc
with said zone of the core and symmetrically 25 tion of said ?eld relative thereto, a core of per
positioned with’respect to said ?uxes, meansfor
indicating the output from said coil, electron tube
means connected to receive the output of said
coil and to supply current to said indicating
meable magnetic material, means including a
source of periodically varying electrical energy
for producing periodically varying ?uxes Yin'a
zone of said core and in opposed bucking rela
means, and means for supplying a potential to 30 tionship, a pick-up coil associated with said core
in said zone thereof and positioned in symmetrical
the plate of said tube means of a frequency sub
stantially twice that of said source.
1
5. In a‘devicesensitive to an external, unidi~
- rectional magnetic ?eld for supplying a signal
relation to said bucking ?uxes, interaction be
tween said device and said external ?eld 'produc4
ing a, periodically varying voltage in said pick-up
voltage output dependent in magnitude upon the 35 coil, means for rectifying the output of said coil,
and indicating means connected to said recti?er
direction of said ?eld relative thereto, a core of
permeable magnetic material, a pair of exciting
means for indicating the relative phase and mag
coils surrounding said core, a source of periodi
nitude of the coil output, said rectifying means
cally varying electrical energy of fundamental
being connected to and controlled by said energy
source whereby to provide said indicating means
frequency for said coils, said coils being arranged
vto produce opposed and bucking exciting ?uxes in
said core, a pick-up coil associated with said core
and so positioned as substantially to buck out any
‘ with
10. phase
In a sensitive
device sensitive
indications.
to an external, uni
,
voltages induced therein by said exciting ?uxes
directional magnetic ?eld for supplying a signal
voltage output dependent in magnitude upon the
but to supply a doubleffrequency voltage output
through interaction with the external ?eld, means
direction of said ?eld relative thereto, a core of
permeable magnetic material, means including a
for indicating the output from said coil, and
source of periodically varying electrical energy
for producing periodically varying ?uxes in a zone
of said core and in opposed bucking relationship‘,
a pick-up coil associated with said corein said
zone thereof and positioned in symmetrical rela
tion to said bucking ?uxes, interaction between
means controlled by said energy source for sub
jecting said indicating means to unidirectional
current from said pick-up coil.
6. In a device sensitive to an external, uni
directional magnetic ?eld for supplying a signal
voltage output dependent in magnitude upon the
said device and said external ?eld producing a
periodically varying voltage in said pick-up coil,
direction of said ?eld relative thereto, a core of
magnetic, permeable material, means including a 55 electron tube means having a control electrode
source of periodically varying electrical energy
thereof connected to receive the output of said
coil, and means for supplying a potential to the
for producing periodically varying ?uxes in a zone
plate of said tube means of substantially the same
of said core and in opposed bucking relationship,
frequency as the frequency of the voltage applied
a pick-up coil associated with said zone of the
core and symmetrically positioned with respect 60 to the control electrode thereof.
11. A magnetic ?eld responsive device com
to. said ?uxes, a zero-center reading meter for
prising a core of magnetic, permeable material,
indicating the magnitude and direction of the
means including a source of periodically varying
output of said pick-up coil, and means controlled
electrical energy'for producing periodically vary
by said energy source for subjecting said meter
ing ?uxes in a zone of said core and in opposed
to unidirectional current from said pick-up coil,
bucking relationship, a pick-up coil associated
the direction of said current being dependent
with said zone of the core and symmetrically posi
upon the phase relationship of the pick-up coil
tioned with respect to said ?uxes, means for indi
output with respect to said energy source.
cating the output from said coil,> electron tube
7. A device of the character recited in claim 9,
means connected to receive the output of said
in which the indicating means includes an indi
cator and two series-connected recti?ers ener
gized from said energy source, said indicator and
pick-up coil being connected between the junc
tion of said recti?ers and a point whose potential 75
coil and to supply current to said indicating
means, and frequency doubling means connected
with said energy source for supplying a reference
potential to the plate of said tube.
'
'
'
12. A device of, the character recited in claim 11
2,410,039
10
in which the frequency doubling means com
prises a recti?er.
bucking relationship, a, pick-up coil associated
with said core in said zone thereof and positioned
13. In a compass device sensitive to an ex
in symmetrical relation to said bucking ?uxes,
ternal, unidirectional magnetic ?eld for supply
ing a signal voltage output dependent in magni
interaction between said device and said external
?eld producing a periodically varying voltage in
said pick-up coil, and means controlled by said
energy source for rectifying the output of said
tude upon the direction of said ?eld relative
thereto, a core of magnetic permeable material,
means including a source of periodically varying
electrical energy for producing periodically vary
ing ?uxes in a zone of said core and in opposed 10
pick-up coil.
LENNOX F. BEACH.
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