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Патент USA US2117462

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May 17, 1938.
w. THAL
2,117,462
SYSTEM FOR MEASURING A COMPONENT OF AN ALTERNATING
‘
CURRENT OR AN ALTERNATING VOLTAGE
Filed July 24, 1936
Y
?ea my
,4 TTORA/E
2,117,462
Patented May '17, 1938'
UNITED STATES PATENT OFFICE
2,117,462
.
SYSTEM FOR MEASURING A COMPONENT
OF AN ,ALTERNATING CURRENT OR AN
ALTERNATING VOLTAGE
‘
Wilhelm_ Thal, Berlin-Siemensstadt, Germany,
1 assignor to Siemens & Halske, Aktiengesell-
schaft, Siemensstadt, near Berlin, Germany, a
corporation of Germany
_ Application July 24, 1936, Serial No. 92,338
_
In Germany July 25, 1935
8 Claims. , (Cl. 175-183)‘
My invention relates to a‘ system for measuring
The voltage required for the test is taken from an
a ‘component of an alternating current or an‘ alternating-current source 2.
alternating voltage, and more particularly to a
system for measuring the loss angle of a con
3 denotes a trans
former, from the secondary winding 4 of which
variable voltages may be' tapped within a rela
tively wide range. 5 is a reference condenser of
In the art of testing electrical values the prob- ' variable capacity and as far as possible free of
lem of determining a component of an alternating losses. 6 is a direct-current measuring instru
current or of an alternating voltage has recently ment; 1 and 8 are separately excited recti?ers,
become more and more important, particularly which are energized by another secondary wind- ing 9 of the transformer 3 and connected in 10
1:) when testing the loss angle, to which an ever
increasing importance is being attached. Bridge Graetz-connection (bridge type‘ recti?er ar
connections are nowadays preferably employed rangement) in series with the measuring instru
for such testings, in the case of which the meas ' ment 6.
The testing circuit proper, in which the object
uring instrument or a connection containing the
is measuring instrument forms the diagonal branch to be tested lies, includes, aside from the object
of the bridge. The aforesaid bridge connections such as the capacity I, also the measuring instru
ment 6 in series with the Graetz-recti?er-connec
are disadvantageous in that they require a rela
1-,
denser orthe like.
tively large amount of energy, since duringvthe
tion. The transformer 3 serves to energize the
disturbance of the bridge balance only a very . standard reference circuit,. comprising the sec
no small portion of the total current ?owing through
' the bridge'also flows through the measuring in
strument.
The disadvantage presented in the above
bridge ‘connections may be removed according to
5 the invention by employing a particular auxiliary
' current or auxiliary voltage circuit in addition to _
a circuit in which the object to be tested is in
ondary winding 4 and the capacity 5 and having 20
in common with the ‘circuit, in which the ‘object
to be tested lies, the branch including the meas
uring instrument and the‘ recti?er bridge. ‘To
explain the operation of the system according to
the invention it will be perhaps preferable to ,con 25
sider that the condenser I to be tested is to be
consideredat ?rst also free of losses. Assuming
that the primary and secondary voltage in the
transformer 3 are exactly 180° out of phase the
30 voltage, which is in synchronism with the com- ,. following results: Through the capacity I ‘flows 30
a predetermined current into the recti?er bridge
ponent not to be measured of the current or of
the voltage to be tested, but in phase opposition and the measuring instrument. The recti?ers
which may be, for instance, of the vibrating reed
thereto. Furthermore, the auxiliary circuit com
prises means for varying the magnitude‘ of the type with separate excitation are so energized
that there is a phase displacement of 180° be 35.
35 current ?owing therein or the value of the volt
age. If now the circuit in which the object to be tween the recti?ers 1 and the recti?ers 8, which
tested lies and the auxiliary current or- auxiliary ’ may be easily attained by poling the exciting
windings of the recti?ers in a corresponding
voltage circuit is connected to the measuring in
strument in such a manner that the» component manner. The secondary winding of the trans
serted. ’ In this auxiliary voltage circuit is pro-'
duced an alternating current or an alternating
40 not to be tested of the current‘ or of the voltage
to be measured may be compensated for by the
former is so connected to the recti?er system as 40
auxiliary current or the auxiliary voltage, only
to counteract the primary voltage. Since in the
auxiliary circuit also a capacity 5 free of losses is
the component ,to'be tested then acts on the
a determining factor as to the position of phase,
Accordingly, ‘ the total , also the two currents are exactly 180° out of
measuring instrument.
45 current ?owing through the object to be tested,
phase. By tapping a corresponding auxiliary
for instance a capacity, may also be supplied to
the measuring instrument so that the accuracy
of the measurement is enhanced to a considerable
voltage from the secondary winding 4 the current
in the auxiliary circuit may be adjusted to the
extent as compared to the measurements attained
50 by the usual bridge connections hitherto‘ em
ployed.
’
‘
-
'
In the accompanying drawing is shown an em
bodimc'nt of my invention in, diagrammatic form.
It is-assumed that, for instance, the loss angle
55 of‘ a condenser denoted by‘ I is to be determined.
45
same magnitude as the current ?owing through
the condenser i. In this case, the measuring in
strument 6 does not de?ect. However, as soon as 50
the object to be tested has a loss angle instead of
freedom from losses the currents in both circuits
are not any longer exactly 180° out of phase.
Therefore, only the component of the current to
be measured which is 180° out of phase with 55
_
2,117,462
. respect to the current in the auxiliary circuit may
be compensated by‘ the latter, so that a residual
reference element of variable reactance in said
reference circuit for balancing the reactance of
amount remains which causes the instrument to,
said testing element, said testing circuit and said
deflect and which represents the component cor
responding to the loss angle of the condenser 8.
When carrying out the measurement it is not
reference circuit having a common branch, a
necessary to balance at ?rst the connection with
said two circuits, and means for balancing the
magnitudes of the component not to be measured
of the testing voltage and of the, corresponding
the aid of a condenser free of losses which re
places the object to be tested, but it su?ices to
10 vary the supply voltage of the auxiliary circuit or
the capacity in the auxiliary circuit in such a
manner that the instrument indicates the
smallest de?ection. In this case the component,
180°, out of phase with respect to the current
15 in the auxiliary circuit, is completely compen
sated for. The ?uctuations of voltage of the
energy source 2 cannot impair the test reading,
'since they in?uence both circuits‘ uniformly.
By the above-described connection a series of
20 other problems besides the above mentioned may
be solved; for instance, the connection may be
employed for measuring the values of the ca
pacitance, the inductance and the like. The
connection is preferably employed in all such
25 cases in which a predetermined component of an
alternatingv voltage or of an alternating current
is to be measured.
measuring instrument disposed in said common
branch so as to be connected to the voltages of
component of said reference voltage, whereby 10
the component not to be measured is compen
sated in magnitude and phase within said com
_mon branch containing said instrument and only
the component to be measured is directly indi
cated by said instrument.
15
3. In_a system for measuring a component of
an alternating clu'rent, an alternating current
source, a testing circuit connected with said
source, a synchronous auxiliary source of alter
nating current in phase opposition to the compo 20
nent not to be measured of the current of said
?rst-mentioned source, a reference circuit 'con
nected with said auxiliary source, means for bal
ancing the component not to be measured of the
current ?owing in said reference circuit and the 25
corresponding component of the current ?owing
in said testing circuit, said testing circuit and said
reference circuit having a common branch, a rec
It is preferable to insert in the circuit a phase
advancer between the secondary winding 9 of the
30 transformer 3 and the exciting windings of the
tifier arrangement of the bridge type connected
recti?ers ‘I and 8 in the manner indicated in my
ing instrument connected in the bridge of said
copending application, Serial No. 93,239, ?led
rectifier arrangement, the recti?ers of said ar
July 29, 1936 in order that the connection may be
employed for a variety of purposes, since it is
35 not necessary in all cases that the voltage of the
auxiliary circuit and the exciting voltage of the
recti?ers be in phase, but certain phase displace
ments must be adjustedin other cases. '
I claim as my invention:
40
__
.
1. In a system for measuring an alternating
current property of an electric element by' meas
uring, a component of a testing current ?owing
through said element, an alternating current
source, a testing circuit connected with said
45 source and designed to include the element to be
tested,- a reference circuit. coupled with said
in said common branch, a direct current measur-v 30
rangement consistingof separately actuated com
mutators, means for actuating said recti?ers syn
chronously with the aforesaid currents and in 35
two timely succeeding groups of 180° phase dis
placement against each other, the recti?ers with
in each of said two successively actuated groups
being designed to simultaneously close the con
nection of said instrument with said common 40
branch, whereby said instrument indicates the
component to be measured.
-
4. In a system for measuring a component of
an alternating voltage, an alternating voltage
source, a testing circuit connected with said 45
source, a synchronous auxiliary source of alter
nating voltage in phase opposition to the com
source, means for producing
said reference cir
cuit a phase displacement of 180° against the ponent not to be measured of the voltage of said
‘current flowing in said testing circuit, a~refer- 1 ?rst-mentioned source, a reference circuit con
nected with said auxiliary source. means for bal
50 ence element of variable reactance in said refer
ence circuit for balancing the reactance of said ancing the component not to be measured of the
testing element, said testing circuit and said voltage of said reference circuit and the corre
reference circuit having a common branch, a sponding component of the voltage of said test
measuring instrument disposed in said common ing circuit, said testing circuit and said reference
circuit having a common branch, a recti?er ar 55
v55 branch so as-to be traversed by said testing cur
rent as well-‘as by said reference current, and rangement of the bridge type connected in said
means for balancing the magnitudes of the com
common branch, a direct current measuring in
ponent not to bemeasured of the testing current strument connectedin the bridge of said recti?er
and of the corresponding component of said ref
arrangement, the recti?ers of said arrangement
erence current, whereby the component ‘not to consisting of separately actuated commutators, 60
be measured is compensated in magnitude and means for actuating said recti?ers synchronously
phase within said common branch containing with the aforesaid voltages and. in two timely
said instrument and only the component to be '
succeeding groups 'of 180° phase displacement
measured is directly indicated by said instru
ment.
2. In a system for measuring an alternating
current property of an electric element by
measuring a component of a testing voltage con-'
nected with said element, an alternating cur
against each other, the recti?ers‘ within each of
said two successively actuated groups being de-' 65
signed to simultaneously close the connection of
said instrument with said common branch, where
by said instrument indicates the component to
70 rent source, a testing circuit connected with said
5. In a system for measuring the loss angle of 70
be measured.
‘
,
source and designed to include the element to be
a condenser, an alternating current source, a
tested, a reference circuit coupled with said
source, means for producing in said reference
circuit a phase displacement of 180° against the
75 voltage connected with said testing circuit, a
testing circuit connected with said source and
designed to include the condenser to be tested,
a synchronous auxiliary source of alternating
current, the voltage of which is in phase opposi- 75
2,117,462
tion to the voltage of said ?rst-mentioned source,
a reference circuit connected with-said auxiliary
source, a reference condenser of variable capacity
and substantially free of losses connected in said
reference circuit, means for balancing the mag
nitudes of the voltages of said two circuits, said
two circuits having a common branch, a recti?er
arrangement of the bridge type connected in said
common branch, a direct current‘ measuring in
10 strument disposed in the bridge of .said arrange
ment, the recti?ers of said arrangement consist
ing of separately actuated commutators, means for
3
a component of which is to be measured, an
auxiliary source of a synchronous current in
phase opposition to the component not to be
measured of the testing current, a reference cir
cuit connected with said auxiliary source, said
testing circuit and said reference circuit having
a common branch, a direct current measuring in
strument disposed in said common branch to be
traversed by the currents ?owing in said two
testing circuit connected with said source and
designed to include the condenser to be tested, a
circuits, two groups of separately actuated phase 10
‘controlled recti?ers arranged in said common
branch, one group being disposed to periodically
close the connection of said direct current instru
ment with said common branch in phase with the
auxiliary currenttof said reference circuit, the
other group being disposed to periodically close
the connection of said instrument with said com
mon branch in phase opposition to said other
recti?ers, means for balancing the magnitude of
the component not to be measured of the test
current and the magnitude of the corresponding
component of said reference current, whereby the
component not to be measured is compensated in
magnitude and phase within said common branch
transformer having two secondary windings and
having its primary winding connected with said
ponent to be measured is directly indicated by
actuating said commutators synchronously with
the aforesaid voltages and in two timely succeed
15 ing groups of 180° phase displacement against
each other, the commutators within each of said
two groups being arranged to simultaneously
close the connection of said instrument with said
common branch, whereby said instrument indi
cates the loss angle of the condenser to be tested.
6. In a system for measuring the loss angle of
a condenser, an alternating current source, a
source, a reference circuit connected with one
of said secondary windings, means for varying the
magnitude of the voltage of said reference cir
cuit in order to balance the magnitudes of the
voltages in said two circuits, a practically loss
free condenser of variable capacity connected in
said reference circuit, said two circuits having a
common branch, a recti?er arrangement of the
bridge type connected in said common branch,
a direct current measuring instrument disposed
in the bridge of said arrangement, the rectifiers
of said arrangement consisting of separately ac
tuated commutators, a magnetic actuating de-.
,40 vice for each commutator, the second secondary
winding of said transformer being connected with
said devices for actuating said commutators syn
chronously with the aforesaid voltages, the con
nections of the actuating devices with said sec
ond secondary winding being disposed to actuate
said commutators in two timely succeeding
groups of _180° phase displacement against each
other, the commutators within each of said two.
groups being arranged to simultaneously close
50 the connection of said instrument with said com
containing said instrument and only the com
. said instrument.
8. In a system for measuring the loss angle
of a condenser, an alternating current source, a
test circuit connected to said source and designed
to include the condenser to be tested, a source of -
a synchronous auxiliary voltage of 180° phase
displacement against the voltage of said- test cir
cuit, a reference circuit connected with said
auxiliary source, a practically loss-free reference
condenser of variable capacity disposed in said
reference circuit, said test circuit and said refer
ence circuit being connected to form a common
branch, a direct current measuring instrument
connected in said common branch, an arrange 40
ment of phase controllable rectifiers for periodi
cally connecting said instrument with said com
mon branch, means for phase controlling said
recti?ers in synchronism with said voltages, said
‘ means being designed to close the rectifier cir
45
cuits connecting said instrument with said com
mon branch during two periods of 180’ phase dif
ference, one of which is in phase with said auxil
iary voltage, and means for balancing the magni
tudes of the voltages of the test circuit and of the 50
reference circuit, whereby
the component of the
/
mon branch, whereby said instrument indicates
1 ztest current ‘not to be measured may be com
the loss angle of the condenser to be tested.
and phase. and the loss
7. In a system for measuring a component of i pensated in
an alternating current, an alternating current‘ angle of the'condenser to be tested is indicated
65 ‘source, a testing circuit connected with said
nuance and designed to lead the testing current,
by said instrument.
WILHIIM 'I'HAL.
@
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