close

Вход

Забыли?

вход по аккаунту

?

код для вставки
Sept 24, 1946.
. '
B E_ LENEHAN
AL
>-
2',4@8,H3 '
ELECTRICAL MEASURING INSTRUMENT
Filed Nov. 10, 1945
_'
-
INVENTORS
?ernardELene/zan
andé‘aaryaJM/ey.
ATTORNEY
Patented Sept. 24, 1946
2,408,218
. UNITED» srATEs PATENT OFFICE
Bernard
Lenehan, Bloom?eld, and George .1. .
~ Wey, East- Orange; N. .L, assignorsto West.-..
' . inghouse Electric Corporation, East Pittsburgh,
3a., a corporationof Pennsylvania
. '
. Application November 10, 1943, Serial No. ‘509,728
1.
coil has aside» positioned for rotation through
this air gapand is so proportioned that itmay
be insertedand removedvwith respect to rthegmag
netic~ structure through thechannel de?ned by
Thisv invention relates to devices: responsive to
the frequency of an alternating electricalquan
tity and ithas particular‘ relation to frequency
measuring instruments having long. -. circular
‘It has been-proposed 111413116‘. prior art'that- de
the tip of thehook-shaped portion.
v
7 It- is, therefore, an; object of the}v invention» to
scales.
'
_
,
vices responsive to the. frequency ofxjan alternat
provide an improved device responsiverto-the-free
ing-current quantity bar-provided‘ with magnetic
quency ' of an; alternating electrical quantity.»
cores. For example, reference may be made to
' ‘It is a-further object of the'invention to pro
the MacGahan Patent 1,549,664 andito the-book .10 vide a frequency measuring instrument compris
ing means responsive to an alternating electrical
entitled “ElectricalInstruments?’ ‘by H. C. Turner,
quantity to be measured for establishing aimag
published~ by Instrumentsv Publishing Company.
netic ?eld wherein ;a;coil. is disposed} for move
However,v in designing a v‘frequency responsive ‘de
ment and; for ‘inducing-‘a- voltage in-ithe'coil; an
‘vice having a long circular scale,'such as one hav
electrical - circuit : having’ inductance‘ and»; capaci
ing anwangular length rinvlexces‘s of 200°,‘a numf- '7
tance'and- including the‘electrical coil; andimeans
ber of‘ problems are presented. ' Among these 7
for introducingan‘ auxiliary; voltage in the-elec
problems are the provision of adequateésensitivity
and torque throughout the'range'of' indication'of
trical circuit.
'
.
It is alstill“ further object: of‘ the invention to
the device While avoidingtoogreat a spre'ad‘be
tween maximum torque and~minimum ‘torque. 20 provide an improved magnetic core for: a; fre
In addition,» it is desirable thatthe device. be-of
quency:measuring'instrument;
ily
serviced.
,
_
-
V
.1 A
‘
‘
-
'
'
'
'
Other objectsof the invention-will be apparent
simple construction, readily assembled and read-
from the following descriptiontaken in-conjunc- »
,tion with the accompanying drawing, in which: ~‘
.
In accordance with‘ the, invention, a frequency
Figure 1 is'a view'in'perspective"with p'ar-ts bro
responsive device, such as an indicating'freduency
meter, is provided with ‘means-responsive to-_-an
alternating current electrical‘ quantity to be meals;
,ured-for establishing a 'magnetic ?eld and‘for
~ ken away ‘ of‘ a frequency measuring" instrument
embodying'tl'ie invention.
'
Fig. '21s a view in top'plan of a magneticstruc
inducing a volt'agein a coil having a'side dis
ture suitable‘for the'instrument of: Fig. 1.
' '
posed’ for‘ movement through’ the ' magnetic ?eld. 30 r "Fig; 3 is‘ a schematiciviewlshowing circuit con
nections suitable for the instrument of '_Fig. l; and
_, The coil is included in an electrical circuit, having
Figs." 4; 5- and 6' are simpli?ed vector repre
inductance and capacitance, thevalue‘of'the-in'g
ductance being dependent on thelposition- of the
‘ sentations of'electrical conditionsv'which' may oc
coil with respect to the, magnetic ?eld‘; The-elec- .. ' cur-in the instrument oflFig. '1.‘ ’
trical circuit is so proportioned "that by proper 35 ' Referring 'to‘the drawing, Fig. 1 shows a fre
quencymeasuring instrument comprising a stator
positioning of the coil the electrical circuit- may
assembly I and. a rotor assembly 3. The rotor
be brought into resonance foreach'freque'ncyto
which the instrument is'designed to‘ respond. ‘ assembly includes a shaft 5 having pivots at its
endswhich are rotatably received insuitable, bear¢
With such a construction, the coil seeks a posi
ing'screws ‘l and 9. A coil II is suitably secured
' tion such, that the electrical circuit is. in'ires
to the’ shaft 5. Inv the'speci?c embodiment of
Fig. l, the coil ll vis cemented to brackets 13 and
‘onance for the’speciflc frequency of the afo'rer
said alternating electrical‘ quantity; In order to
15 which are securedto the shaft 5.
decrease the ratio. of the maximum
' mum torque exerted‘ on the coil, provisr
The shaft 5v also supports a; pointerrl'l which
_
has an end positioned for movement adjacent a
circular'scale l9. It will be noted that the point
er l1 and‘ the coil II are on opposite sides of the
for ‘introducinginto ther'eSonant electricalv cirl.-' '
cult ‘an auxiliary voltage having the-53mg he,
Quenc'yas that of ‘ the alternating fe1gct17i¢a'_1' (mane
shaft
Consequently, the pointer I1 balances,
, For establishing, the required‘ magnetic" paths, 2,50 at leastin part, the coil l I.‘ If the pointer slight
titytol be
measured;
'
'
'
>
-
-
'-
.
ly overbalances ' the coil, adjustable balance
the ' instrument includes a‘rmagneticf' structure
weights 2| may; be secured to the shaft 5',‘ as
7 formed of laminations. 7' Each-‘ofxthe'vlaminations '
includes a hook-shaped portion’ providing ' a sub
stantially‘ annular-bore and“ an outer ‘magnetic
V
Rotation of the rotor 3 is dampedby means of 7
an ‘electroconductive damping disk ,‘23' secured‘ , to
therewith
element‘spaced‘
a substantially'annularfrom the annular core
air gap.
to: define
The 55 the shaft E'and' formed of a material such as
2,408,218
3
4
aluminum. This disk 23 rotates between the
poles of a permanent magnet 25 to damp rota
in the art.
It is desirable at this point to note that the
self-inductance of the coil || depends on its po
sition with reference to the magnetic structure
41. This may be explained with referenceto
Connections to the coil H are made through
?exible conductor strips 21 and 29 which have
tioned adjacent the end 59A of the annular air
torque in response to a deviation of the frequency
being measured from the indicated value. In
a speci?c instrument designed in-accordance with
trolled by the shape of theair gap. For example,
if it is desired that the self-inductance of the
tion of the shaft 5 in a manner well understood
Fig. 2, if it is assumed ?rst that the coil is posi
gap 59. When the coil II is so positioned, sub
their inner ends secured respectively to insulat
stantially all ?ux passing there through is dis
ing collars 3| and 33 secured to the shaft 5.
The outer ends of the spiral conductor strips 2.1.’. 10 tributed over substantially the entire air gap 59.
Since the air gap has a large cross section the
and 29 are soldered or otherwise secured to lugs
reluctance offered to the magnetic ?ux is com—
35 and 31_which are ?xed with respect to the
paratively small and the self-inductance of the
stator I. Connections from external electrical
coil II is large. On' the other hand, if the coil
elements to the lugs may be effected through
is positioned adjacent the'opposite end 59B of
suitable conductors 39 and 4|. The coil H is
connected through conductors 43 and 45. respec 15 the air gap,.magnetic ?ux passing through the
coil passes through an extremely small portion
tively. to the inner ends of the conductor strips
21 and 29. As shown in Fig. l, the spiral con- , of the annular air gap. Consequently, the re
luctanceoffered to such magnetic flux is com
ductor strips 21 and 29 are wound about the shaft
paratively high and the self-inductance of the
5. Although the conductor strips are extremely
?exible, thev have a little resilience. Since the 20 coil is substantially smaller than that of the coil
when'the coil is ‘positioned adjacent the end 59A
shaft 5 is designed for a large angular movement,
of the "air gap‘. ‘At intermediate positions of the
such as one in eXcess of 200°, it is convenient to
coil, the self-inductance of'the ‘coil has interme
adjust the conductor strips so that they are un
diate values. '
‘
‘
stressed when the coil H is adjacent a position
The variation in self-inductance of the coil H
wherein the instrument develops a minimum
as it moves through the air gap 59 may be con
coil decrease at a more rapid rate as the coil
the invention, the conductor strips were posi
tioned to be unstressed when the pointer indicat» .30 moves from the ‘end 59A to the end 59B of the
air gap, the magnetic structure 41 may be con
ed approximately two-thirds of the full scale
structed to provide an air gap 59 having a length
value.
L which increases from-a predetermined value
The stator includes a magnetic structure 41
adjacent the end 59A to a larger value adjacent
for‘ establishing a magneticv ?eld within which
the end 59B. Alternatively, the magnetic struc
a portion of the coil H is disposed for rotation
ture may be constructed to provide‘ an annular
and for directing magnetic flux through the coil
air gap having a- uniform length L but having a
||. The magnetic structure 41 comprises a hook
width W which decreases from a predetermined
shaped magnetic inner part 49 having a hook
value adjacent the end'59A to a smaller value ad
portion 5| and a shank portion 53. It will be
observed that the hook portion 5| provides a 40 jacent the end 593 of the air gap. The desir
ability of such variations in the air gap will be
substantially annular magnetic core having a
discussed below.
9
channel 55 therein (see Fig. 2). The magnetic
Suitable electrical connections for the instru
structure 41 includes further ‘an outer magnetic
ment of Fig. 1 are-illustrated in Fig. 3. In Fig. 3,
element or portion 51 which surrounds and is
spaced from the'hook portion or annular mag 45a pair of-conductors 1| and 13 represent an elec
trical circuithaving an alternating voltage there
netic core 5| to de?ne'therewith an annular air
across. The-winding BI is connected across the
gap 59. This air gap has a width W (Fig. 1) and
circuit for energization in‘ accordance with the
a length L (Fig. 2). By inspection of Fig. 1, it
aforesaid alternating voltage. .Energization of
will be observed that the coil “links the an
nular magnetic’ core-5| and has a side disposed 50 the Winding 6| establishes a magnetic ?eld for
the coil | | and also directs magnetic flux through
for movement‘ through the annular air gap 59.
the coil | | to induce any alternating voltage there
It should be observed further that the coil II is
in. ' The coil II is included in an electrical circuit
proportioned to pass through the‘ channel 55
14 vhaving inductance represented by the coil H
(Fig. 2) in response‘ to movement of the rotor in
an axial direction. This permits the coil to be. 55 and an inductance coil 15 and having a capaci
tance ‘represented by a capacitor 11. To decrease
inserted in operative position or to be removed
the size of the capacitor 11 required, the capacitor
therefrom without disturbing the magnetic
is connected to the electrical circuit through an
structure 41.
I
auto-transformer 19, the high voltage side of the
For energizing the instrument illustrated in
Fig. 1, a winding 6| surrounds the shank por 60 auto-transformer being across thecapacitor 11.
To facilitate calibration, one or more of the cone
tion 53 of the magnetic structure 41. When an
nections to the auto-transformer 19 are through
electrical current is passed through the winding
adjustable taps.
6|, magnetic ?ux is directed in series through
In response to the voltage induced in the coil
the shank portion 53, the annular magnetic core
II, a current flows through the electrical circuit
5| and the air gap 59, as shown by dotted lines .
14. ’However, the voltage induced in the coil II
in Fig. 2. Since a portion of this magnetic flux
is dependent on the position of the coil with re
passes through the coil II, a voltage is induced
spect to the magnetic structure 41. Referring
in the coil. Furthermore, a side of the coil H
again to Fig. 2, when the coil is adjacent the end
is disposed‘for movement through the magnetic
?eld produced by the magnetic flux crossing the 70 v59A of the air gap substantially all the magnetic
?ux passing. through -.the air gap also passes
annular air gap 59. For a purpose hereinafter
through the coil. . Consequently, a substantial
pointed out, an auxiliary winding or coil 63 is
positioned on the shank portion 53. If desired,
voltage is induced in the coil | | . However, when
the coil ,| | is adjacent. the end 59B of the air gap,
the magnetic structure 41 may include a notch
65 for receiving the auxiliary winding 63.
v75 very little of the magnetic ?ux passing through
9,408,218
5
6
the air gap. passes through; they coil. Therefore,
the’ voltagainduced therein. is. comparatively
small. This difference in voltage, if large, isv ob
jectionable for the reason that to provide ade
quate torque when the coil is adjacent the end
5930f the annular airgap, an extremely large
torque is applied to the coil when. the coil is: ad'
jacent the end 59A of the air gap. A. large torque‘
current 12- (Fig. 5) ?ows through the circuit 714.
vIn ?owingrthrough‘the. coil II. the Current 12
produces a magnetic ?ux ¢2. The component
of-Ithe magnetic ?ux ¢2, which is in phase with
the. magnetic ?ux ¢, represents a torque T2
‘which is. applied to the coil II. 'In' response to
this torque the coil ll moves until the pointer
l1 indicates a frequency of 50 cycles per second
on the scale l9. Atthis point, the inductance
10 of the coil_ I l’has changed to a value which makes
coil and associated portions» of the instrument.
the electrical circuit" resonant at a frequency
To decrease‘ the variation ofi'curren't'in the
of~50 cycles per second and the vector relation
electrical circuit 14 resulting from. .a: variation
ships again are similar to those illustrated in
in» the positionyof the-coil? Hi withrespect to the
may- resultin excessive stress and vibration'iin the
magnetic structure 41., an auxiliary voltage is
Fig. 4".
>
-
Let it be assumed‘ that the instrument of Fig.
introduced into the electrical circuit. a This volt
agemay be obtained directlyrfrom the conductors
"H and 13 through a suitable phase control device
1 is indicating a. frequency of 60 cycles per sec-' '
0nd and that the frequency applied to the wind
ing 6| increases suddenly to a value" of 70 cycles
per second. Since the electricalicircuit 74 initi
for’ maintaining the auxiliary voltage substan
tially in phase with th'e'voltag'e’ induced in the '
coil ll. Preferably, the auxiliary voltagehisi in 20 ally is resonant for a frequency of 60 cycles per
second, the circuit for a frequency of 70 cycles
troduced by means of the auxiliary‘ winding 63
per second offers a substantial inductive imped
which is inductively coupled to the winding 6|.
Since the same magnetic flux-passeslthrough the
windings 63 and H, the voltages induced therein
1 are in phase. The auxiliary voltage induced in
the winding» 63 is substantially independent of
ance to the flow of current. Consequently, in
response to the voltage V a current I3 ?ows
25 through the circuit. The current as shown in
Fig. 6 lags the voltage V, and produces a mag
netic ?ux ¢3 when ?owing through the coil H.
thoposition of the coil H with respect to the
magnetic structure 41. For this reason, theratio
The component of the magnetic flux¢3 which is
projected on the line of the magnetic ?ux c rep
of-the- maximum to the minimum torque applied
to the coil Il may beheld ‘to/Ia reasonably small
value,
v
~
'
resents a torque T3 acting on the coil H.
This
torque is directed oppositely to the torque T2 of.
Fig.‘ 5 and urges the pointer I ‘I up-scale to a posi
tion indicating a frequency of '70 cycles per sec
I
The operation of the measuring instrument il
lustrated in Fig. 1 and connected as shown in Fig.
3, may be considered withreference to the par‘
ond. The resulting movement of the coil ll re
duces the inductance of the coil H to a value '
tial vectorrepresentationsof Figs. 4', 5» andr6;
When the winding 61 is ‘connected to the circuit
whichmakes'the electrica1 circuit 14 resonant
represented by the conductors 'H- and 13',‘ m'ag- ‘
at a» frequency of 70 cycles per second.
netic ?ux ?ows in the magnetic structure 41.
This‘magneticflux isrepresentedv in Figs. 4,5 and
voltage across the winding 6| is an alternating
voltage having a frequency of;6.0 cycles per-secs
fore, with the pointer I1 indicating a frequency
of 70 cycles per second, the vector relations in
the circuit‘!!! are similar to those represented
in Fig. 4 and the pointer ‘ll remains stationary.
From this brief review of the operation of the
0nd;
instrument, it will be appreciated’ that the coil
6 ‘by the vector ¢.
Let‘ it. be assumed that the; ..
Since the coils’ Hand 6.3 are-inductively .
There
coupled to the winding 5!, the alternating ?ux ¢
l_l always seeks a position such that the electrical
in the magnetic structure 4-‘!v induces ‘voltages in v i
circuit 14- is brought into resonance for the fre- '
quency of the‘alternating voltage applied to the
the coils II and 63“Whi0h‘ are in'ph'asewith each
other. The sum of these two voltages is. repre-.
sented/ in Figs. ‘1,5 and 6 by the vector V which
lags the flux ¢ by an angle of 90°. The voltage
winding
61.
’
'
.
,
"
The» scale distribution of the instrument is de
termined by the rate at which the self-inductance
V produces a flow of current in the electrical cir- ; i of the coil H changes in response to movement
cuit 14.
The parts are so proportioned that if
of the coil with ‘respect to the magnetic struc- ‘
ture 41. 7 To provide a linearscale, the annular
‘magnetic core '5! is tapered‘as shown in Fig. 1
1This tapering of the annular magnetic core is
the pointer’ H indicates a .frequency'of.6‘0'cycles
per second on the scale-19,.as shown» ‘in? Fig. 1,'
the electrical circuit 14 is- resonant-at a. fre-,
quency of 60cycles .per second. Under these con
such that the cross section of the annular-‘mag
ditions, the electrical circuit. 14', offers an .i'm-.
pedance to the ?ow of current whichis repre
sented only by the resistance of the circuit and
the current which ?ows in the circuit is in phase
with the voltage. V. This current is represented an
in Fig. .4 by the vector-I. In ?owing ‘through the
netlc core and the width of the air gap de
crease from predetermined values adjacent the
vend 59A of the air gap to smaller values ad
' jacent the end 59B of‘ the air gap.’
The magnetic structure 41 may be constructed
in any suitable manner from a soft magnetic
coil H, the current I produces a magnetic flux
material, such as a-good grade of soft iron.
which is represented in Fig. ,4‘ by the vector ¢'|.
desired, the material employed for the magnetic
If
It will'be noted that the vectors it and‘ ¢l are in ‘ . structure may be similar to that shown in Patent
quadrature. Consequently no torque is applied
to the coil lhl and'the pointer I'ljcont'inuously in
dicates a frequency of 60 cycles per second.’
Let it be assumed next ,that [the frequency
drops suddenly froma value of 60 cycles-persec
ond to a value of 50 cycles perisecond. Since
the electrical circuit >14 initially‘ is resonant for
a frequency of 60 cycles per ‘second, thecircuit
offers at a frequency’ of‘ 50 cycles per second a
"substantial capacitive impedance‘ to the ?ow ‘of
(15
7N0. 1.807.021, of T. D.‘ Yensen, issued May 26,
1931, which is available on the market under
the trade name “l-Iipernik.” The material‘dis~
closed in this patent is a low hysteresis loss heat
treated magnetic alloy comprising iron and nickel
in approximately equal proportions. Conven
iently, the magnetic structure 41 may be formed
from a. plurality of magnetic laminations M. Ml,
M2, M3, M4, M5 which are attached'to each other
in any suitable ‘manner. as. by means'of rivets
current. , In response-to the voltage 7V, a leading -75 8|. The laminations all may be of. substantially
2,408,218
7
the same con?guration but certain of the lamina
tions Ml have their tips cut oii along“ the line
'83 (Fig. 2). Other laminations M2, M3, M4, M5
have their tips cut off along the lines, respec
tively, 85, 81, 89 and M. This provides an an
nular magnetic core 5i which tapers to provide
the desired rate of change of the inductance of
said coil for movement relative to said magnetic
structure to direct said portion through'said air
gap, means associated with said magnetic struc
ture and responsive to, the alternating quantity
tobe measured for directing a magnetic flux
through said'air gap and through said coil, said
magnetic structure being con?gured to effect a
the coil H in its rotation through the air gap.
change in inductance of said coil as said; coil
It will be observed that the lines 83; 85,81, 89
moves through said air gap, a circuit containing
and 9| are not radial with‘ respect to‘ the shaft 10 inductance and capacitance, said circuit includ
ing said coil and being proportioned to be res
5. As clearly shown in Fig. 2, these lines-are
onant for the range of frequencies to which said
inclined to provide a gradual change in'cross
sectionof the core as the coil ii moves there
across. The laminations may be assembled in
any desired sequence. Preferably, one or more of
the laminations Ml are applied to each face of a
stack of the laminations M. The laminations
M2, M3, Mil and M5 are then applied succes
sively to each face of the resulting stack to pro
vide the stepped formations illustrated in Fig.
1 on each side of the laminations M.v This de»
sign assures a magnetic structure or substantial
rigidity.
'
device‘is designed to respond, whereby magnetic
?uxpassing through said coil causes current to
flow in saidv circuit having a phase relationship
relative to the magnetic ?ux in said air gap which
is dependent on the deviation of the frequency
or the alternating quantity to be measured from
the value corresponding to the position of ‘said
coil relative to said magnetic structure, a sub
stantial portion of the inductance in said circuit
having a non-magnetic core, and auxiliary means
for energizing said‘circuit in accordance with the
alternating quantity to be measured.
The current ?owing through the electrical cir
2. Ina device responsive to thefrequency c
cuit ‘l4 depends on the voltage applied-to the
‘an alternating electrical quantity, a magnetic
winding 6i and on the characteristics of- the
structure comprising a substantially annular
electrical circuit. It is desirable that a substan
magnetic core and a magnetic element spaced
tial portion of the inductance in the electrical
from said annular magnetic core to de?ne there
circuit ‘id be independent of the current flowing
in the circuit. To this end‘, the inductance 75 30 with a substantially annular air gap, a coil linked
preferably is substantially an air core inductance.
with said annular magnetic core, said coil having
Such an inductance substantially eliminates
a‘ portion positioned in. said air gap, >means
errors resulting from changes in the voltage ap
mounting said coil for rotation relative to ‘said
magnetic structure to carry said portion through
plied to the winding 5 I.
vAs previously explained, the calibration of the
the air gap, said magnetic structure being con
instrument may be controlled by adjusting the
ratio of the primary turns of the autoetrans
?gured to change the-inductance of said coil as
the coil rotates with respect to said magnetic
structure, means associated with said magnetic
dition, a ?ne adjustment may be provided‘by
structure for directing through said air gap and
positioning a magnetic screw 93 for movement 40 through said coil alternating magnetic ?ux de
into and out of the magnetic ?eld of theinduc
pendent'on‘an alternating quantity to be meas
tance coil 15.. By an adjustment of the screw
ured, whereby an alternating voltage is induced
93, the inductance of the coil ‘I5 may be varied
in said coil, a circuit containing capacitance and
former T9 to the second turns thereof. ~ In ad
11 which has no temperature error; As a- gen
inductance, said circuit including said coil,
whereby said voltage produces a flow of current
through said circuit having‘ a phase relationship
eral rule, a commercial capacitor has avalue of
relative to said magnetic flux whichis dependent
to calibrate the electrical circuit.
-
-
In practice, it is difficult to provide a capacitor
capacitance which increases with temperature.
on the deviation of said circuit from resonance,
This increase may be'compensated' by a position
and'a'uxiliary means for introducing a voltage
50
ing in the magnetic ?eld of the inductance coil
in said circuit dependent on the alternating quan
‘l5, a magnetic element 95 having a substantial
negative temperature coe?icient of permeability.
tity to, be'imeasured,
_
,
_
3. 'In a device responsive to the frequency of
an alternating electrical quantity, a magnetic
As well understood in the art, a magnetic ele
ment having such a coefficient may be formed
of an iron alloy containing 30% nickel; Such 55 structure ‘comprising a substantially annular
magnetic core, a magnetic element spaced from
alloys are known as temperature compensator
alloys.
'
-
As previously explained, the inductance coil 15
is
essentially
an
air
core
inductance.
The '
‘said annularmagnetic core to’de?ne therewith
a substantially .annularair gap, and a_ magnetic
member connecting saidnmagnetic core to said
amount of iron added by the screw 93 and the 60 magnetic element, said magnetic core having a
channel extending from the interior to the ex
element 95 is small and the inductance coil 15
.terior thereof adjacent said magnetic member, a
has, to a substantial extent, an inductive re
coil linked with ‘said annular magnetic core, said
actance which is independent of the value of
coil having a portion positionedin said air gap,
the current ?owing therethrough.
Although the invention has been described 65 means mounting said coil for rotation relative to
said magnetic. structure to carry said portion
.through .the air gap, said magnetic structure
being configured to change the inductance of said
Therefore, the invention is to be restricted only
coil as the coil rotates with respect to said mag
by the appended claims as interpreted in view
70 netic structure, and a winding associated with
of the prior art.
with reference to certain speci?c embodiments
thereof, numerous modi?cations are possible.
We claim as our invention:
1. In a device responsive to the frequency of
an alternating electrical quantity, a magnetic
structure having an air gap, a coil having a por
‘said magnetic structure and effective'when suit
ably energized for directing through said air gap
and through said coil alternating magnetic ?ux
dependent on an alternating [quantity to be meas
tion positioned in said air gap, means mounting 75 ured,‘ whereby an alternating voltage is, induced
2,408,218
in said coil, a circuit containing capacitance and
inductance, said circuit including, said coil;
whereby said voltage produces a ?ow of current
through said circuit having a phase relationship
relative to said magnetic flux which is dependent
in the deviation of said circuit from resonance,
said coil being proportioned for removal from
said magnetic structure through said channel.
4. In a device responsive to the frequency of an
10
through said channel, means mounting said coil
for rotation substantially about the axis of said
annular magnetic core, and a circuit having ca
pacitance and inductance, said circuit including
said coil and being proportioned to be resonant
for the range of frequencies to which said device
is designed to respond, and an auxiliary wind
ing linked with magnetic ?ux produced by said
?rst-named winding, said auxiliary winding being
included in said circuit.
electrical quantity, a magnetic
6. In a device responsive to the frequency of
structure comprising a substantially annular
an alternating electrical quantity, a magnetic
magnetic core having a channel extending from
structure comprising a plurality of aligned mag
the interior to the exterior thereof, a magnetic
netic laminations, each of said laminations com
element substantially surrounding said annular
magnetic core but spaced therefrom to de?ne an 15 prising a hook-shaped magnetic inner part hav
ing ashank portion and having a, hook portion
annular‘ air gap therebetween, and a magnetic
terminating in a tip, a magnetic outer part sur
> alternating
member adjacent said» channel for connecting
_ said annular magnetic core to said magnetic ele
ment, said magnetic structure being con?gured to
provide the annular air gap with different re
luctances at various angular positions around the
axis of the air gap, a winding associated with
said magnetic structure, said winding when en->
ergized in accordance with said electrical quan
tity being effective for directing alternating mag
netic ?ux through said annular magnetic core
and said air gap, a coil linked with said annular
magnetic core, means mounting said coil for ro
tation substantially about ,the axis of said an
nular magnetic core, and a circuit having ca
pacitance and inductance,'said circuit including
said coil and being proportioned to be resonant
for the range of frequencies ,to.which said device
is designed to respond.’
,
V
5. In a device responsive to the frequency of an
alternating electrical quantity, a magnetic struc-,
ture comprising a substantially annular magnetic
core'having a channel extending from the in
terior to the ‘exterior thereof, a magnetic ele'_
ment substantially surrounding said annular
magnetic core but spaced therefrom‘ to de?ne an
annular air gap therebetween, and a magnetic
member adjacent said channel for connecting
said annular magnetic core to said magnetic ele',-,
ment, said annularmagnetic core having a radial
cross-section which diifers at successive points
‘ around said core, a winding associated with said
magnetic structure fordirecting ‘magnetic’ flux
through said annular magnetic core and said air
gap, a coil linked with said annular magnetic
core, said coil being proportioned to be inserted
in'and removed from said magnetic structure
rounding, and spaced from a substantial portion
of the hook portion to de?ne therewith an arcuate
air gap, each lamination forming a path for mag
netic ?ux wherein said inner part, said air gap
and said outer part are in series, certain of said
laminations having tips terminating short of the
tips of other of said laminations to provide a re
sultant hook portion varying in cross-section, a
coil linked with the resultant hook portion, and ,
means mounting said coil for rotation relative to
said magnetic structure.
7. In a device responsive to the frequency of an
alternating electrical quantity, a magnetic struc
ture comprising a plurality of aligned magnetic
laminations, each of said laminations comprising
a hook-shaped magnetic inner part having a
shank portion and having a hook portion termi
nating in a tip, a magnetic outer part surround
ing and spaced from a substantial portion of the
hook portion to de?ne therewith an arcuate air
gap, each limination forming a path for magnetic
?ux wherein said inner part, said air gap and said
outer part are in series, certain of said one of said
laminations having tips terminating short of the
tip of said last-named lamination to provide a
resultant hook portion varying in cross-section, a
.coil linked with the resultant hook portion, means
mounting said coil for rotation relative to said
magnetic structure, and means positioned adja
cent the shank portions of said laminations for
directing magnetic ?ux through said path formed
by each of said laminations.
BERNARD E. LENEHAN.
GEORGE J. WEY.
Документ
Категория
Без категории
Просмотров
0
Размер файла
959 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа