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Патент USA US2411122

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NOV. 12, 1946.
A_ WIN-[HER
2,411,122
ELECTRICAL COUPLING CONTROL APPARATUS
Filed Jan. 26, 1944
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Nov; 12, 1946.
A. WINTHER
2,411,122
ELECTRICAL COUPLING CONTROL ALPARATUS
F'iled Jan. 26, 1944
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Nov. 12, 1946.
A. WINTHER
2,411,122
ELECTRICAL COUPLING CONTROL APPARATUS
Filed Jan. 26, 1944
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Patented Nov. 12, 1946
2,411,122
UNITED STATES PATENT OFFICE
2,411,122
ELECTRICAL COUPLING CONTROL
APPARATUS
Anthony Winther, Kenosha, Wis., assignor to
Martin P. Winther, as trustee -
Application January 26, 1944, Serial No. 519,783 ‘
20 Claims.
(Cl. 172-—284)
1
2
This invention relates to electrical coupling
control apparatus comprising a transfer control
‘other application of the invention to engine
testing dynamometer apparatus; and
circuit and its controlled apparatus, and with re
gard to certain more speci?c features to a cir
wiring diagram of Fig. 1 showing alternative con
cuit for controlling and quickly transferring elec
nections for accelerating load transfer, particu
trical energization from one electrical load re- .
larly in applications such as shown in Fig. a.
quiring direct current excitation to another re
quiring it, such as in certain operating combina
sponding parts throughout the several views of
tions of electromagnetic slip clutches, brakes,
the drawings.
Fig. 5 is a reproduction of a part of the main
Similar reference characters indicate cor
dynamometers and the like.
Referring now more particularly to Fig. 1, M
10
Among the several objects of the invention may
is an A. C.-motor having a drive shaft DS driving
be noted the provision of a transfer circuit which
the armature A of an eddy-current, electromag
will quickly accomplish transfer of current en
netic slip clutch C. At F is the driven ?eld mem
ergization from one exciter to another, for ex
ber of clutch C having ?eld Winding L. This
ample in coupling, brake and dynamometer appa 15 winding L is energized from a circuit to be de
ratus of the electromagnetic types, transfer be
scribed, via slip rings SR. The ?eld member is
ing in response to load or incipient speed changes,
carried on drive shaft SH. Shaft SH also carries
the provision of apparatus of the class described
an attached armature RO—2 within a ?eld mem
which will exert accurate speed control functions
ber ST of an eddy-current electromagnetic brake
on a driven member over a wide range of speed 20 BR. Brake BR has a ?eld winding 33. On the
reductions; the provision of a circuit of the class
shaft SH is carried the armature U of a small,
described which is particularly applicable to
permanent-magnet, speed-responsive, control
transferring excitation loads between exciters of
generator GN.
various units such as dynamometers, slip clutches
Shaft SH is coupled in driving relationship with
and brakes of the electromagnetic types, in or 25 a grinding-wheel load W, which is one, but not
der to obtain said accurate speed control of units
the only, example of the type of mechanical load
driven therethrough even under conditions of
governed by the apparatus of the invention. It
wide variation in mechanical load; and the pro
is illustrative of a mechanical load member which
vision of a circuit of the class described which
may tend to overrun, or drop its load completely
will effect reliable transfer operation under both 30 from the driving member, and which should have
light and heavy excitation requirements. Other
its speed governed. It is a development in mod
objects will be in part obvious and in part pointed
ern grinding machines. In these machines the
out hereinafter.
'
work to be ground is driven in the same tangen
The invention accordingly comprises the ele
tial direction at the point of contact with .the
ments and combinations of elements, features of 35 grinding wheel as the periphery of the wheel, and
construction, and arrangements of parts and cir
overrunning it, whereby a better ?nish is obtained,
cuits which will be exempli?ed in the devices
which is more accurate, and of a higher degree of
hereinafter described, and the scope of the ap
polish. However a di?iculty is involved during
plication of which will be indicated in the follow
certain parts of the operation, as for example
ing claims.
40 when the grinding is very light. Under such con
In the accompanying drawings, in which are
ditions the work tends to overdrive the grinding
illustrated several of various possible embodi
wheel, with which it has direct contact. The
ments of the invention, ’
result is that the grinding wheel tends to rotate
Fig. l isa schematic layout showing one appli
faster than it should for best results. Therefore
cation of the invention to a grinding machine;
it is necessary not only to have a source of power
Fig. 2 is a main wiring diagram;
to drive the wheel, but the same source should
Fig. 3 is an auxiliary wiring diagram of selected
be capable of retarding the wheel and holding it
parts of Fig. 2, rearranged to display certain
at a given rotary speed against overdriVing, The
bridge-circuit relationships;
present invention will, among other things, ac
Fig. 4 is a diagrammatic layout showing an
complish this.
2,411,122
3
4
Fig. 1 is a schematic arrangement illustrating
the application of the invention to such a load.
The A, C. induction-type motor M operates the
drive shaft DS. This drives the driven shaft SH
through the electric slip coupling or clutch C of
the eddy-current type identi?ed above. The ar
mature A is an eddy-current member surround
ing a radiating polar ?eld from ?eld coil L. The
toric ?ux ?eld generated by annular coil L and
the polar member F interlinks armature A in
which flux-reactive eddy currents are generated.
The degree of electro-magnetic coupling depends
upon the ?eld strength of coil L and hence upon
its excitation. The rotor RO-Z of brake ER is
an eddy-current member within a surrounding
polar ?eld emanating from brake coil B. The
toric ?ux ?eld generated by annular coil B and
the ?xed polar member ST interlinks the rotor
RO--2 in which reactive eddy currents are en
citing units L and B. Excitation of L tightens
the clutch coupling for acceleration upon incip
ient speed decrease (brake B deenergized). Ex
citation of B increases braking for deceleration
upon incipient speed increase (clutch C deener
gized).
The tubes l and 3 are both grid-controlled
gas-?lledtubes, commonly used for power appli
cations and characterized by the fact that al
though the grid of each tube can start the anode
current, the grid cannot shut it off. However,
when the alternating anode voltage passes
through zero, the current dies out automatically.
The e?ect of the grid action is to start the respec
tive tube ?ring at one point or another on one
swing of the A. C. anode voltage wave. Di?erent
total average D. C. currents are passed as deter
’mined by the grid action.
The tubes 2 and 4 are similar but are not grid
gendered. Thus energization of_ the coil B may 20 controlled, as indicated in the drawings. They
produce a retarding e?ect on the shaft SH. The
are recti?ers of substantially the same current
circuits to be described are carried in a box Ov on
capacity as tubes l and 3.
'
which is a' control handle H for a potentiometer
arm PA to be speci?ed. The transfer circuits re
At AT is shown an anode transformer having
excitation between coils L and B for closely con
trolling speed of the shaft SH under even the
most adverse conditions of mechanical and other
one phase of a three-phase A. C. supply circuit
.AC. Thus the secondary component ST-l ap
a primary PA and secondary components ST—I
spond to current from generator GN to transfer 25 and ST-2. The primary PA is connected across
load variations.
,
plies an alternating voltage to the anode of tube ,
3. Whenever the grid G~—l and anode of tube 3
Detailed examples of eddy-current clutches 30 are positive enough, its cathode K-—1 passes cur
rent toward the anode and through the clutch
such as C are shown in U. S. patents, 2,286,777;
coil L, to points T-?, T—2, wire W—-'I and mid
2,286,778; 2,287,953 and others. Detailed exam
ples of eddy-current brakes such as BR are
point T-I5 of a cathode, secondary component
KW of a general supply transformer FT. It then
shown in U. S. patents, 2,286,777; 2,306,582 and
others. A permanent-magnet generator such as 35 returns to the cathode K—'l of tube 3 via lines ,
' W—'l or W-2_ The primary PF of transformer
GN is shown in U. S. Patent 2,277,284.
FT is connected across another phase of the A. C.
Hereinafter potentials and current ?ow will be
treated in terms of the movement of negative
electrons in the respective circuits. For example,
an element in a tube from which negative elec
trons emanate will be designated negative; an
element which they enter will be designated pos
itive. Also, if negative electrons are copiously
supply. Thus the tube 3 becomes a half-wave
recti?er and the current flowing through it oc
40 curs only‘ within that period of the A. C. cycle
when the grid-controlled anode of tube 3 is posi
tive.
Since coil L has a relatively high inductance
and. since it is in a direct current unit, energy
available to a ?rst element and not to a second
element of the same circuit, then the second ele 45 is stored in it during the period in the cycle of
current increase. When recti?ed current ceases
ment will be considered to be positive relatively
to ?ow from the tube 3, this stored energy in
to the ?rst.,
the coil L and the voltage, by the incipient col
Referring more particularly to Fig. 2, the cir
lapse of the ?ux surrounding the coil, has a
cuit sections I and I-A are the principal rectify
tendency to prolong the current in the same direc
ing portions of thecircuit. Circuit II constitutes
tion in the circuit last, above enumerated. How
a reference voltage circuit; III, a governing cir
ever, since the tube 3 is non-conducting when the
cuit; IV, an ampli?er circuit; and V is a bridge
anode. becomes negative, this follower current
circuit.
from the coil L by-passes tube 3 and takes a
In circuit I, which is in a principal recti?er
path through tube 4 which was inactive when
section, is a grid-controlled clutch control recti
the tube 3 was active. Tube 4 is inactive during
?er tube 3 and discharge tube 4, together with
the time that tube 3 is active, because the anode
clutch excitation load L. In .the present exam
of tube 4 is connected to the negative terminal
ple, the load L is the D. C. excitation coil of the
of AT when the anode of tube 3 is positive. Thus
electromagnetic, eddy-current slip clutch C of
60 under the tendency of coil L to discharge, tube 4
Fig. 1.
prolongs the current through the coil. The result
At I—A is shown a parallel related and simi
is that an average current in coil L may be
lar recti?er section in which is a grid-controlled
maintained with substantially no interruption
brake control recti?er tube l and a discharge
until desired, even though the tube 3 is a half
tube 2, together with load B. Load B is the exci
tation coil of the electromagnetic, eddy-current ' wave recti?er. The passage of current through
tube 4 is substantially determined by the value
brake BR of Fig. l, for example. An object, as
of the current established by the tube 3.
indicated above, is to transfer excitation or elec
The object of the tube by-pass arrangement is
trical load from the coil L to the coil B, and vice
three-fold: (1) It e?ects economy in each rec
versa in response to certain changes, such as me
ti?er system by using only one grid-controlled
chanical load changes, incipient speed changes,
tube, which is more expensive than the vgridless
or both, the object being to hold the speed of
recti?er; (2) it relieves recti?er tube 3 of high
shaft SH substantially constant despite said
inverse voltage which the direct current would
changes. For best control this requires from
otherwise apply to its cathode and anode during
time to time quick transfer of the excitation load
' reversal of the A. C. cycle of potentials applied
from one to another of the clutch and brake ex
5
2,411,122
6
to the tube 3; and (3) it simpli?es the circuit.
circuit II.
In short, the use of the tube 4 is as a plain rec
ti?er which serves to discharge the coil L through
a low-resistance by-pass, thus economizing tubes,
will appear hereafter.
circuit parts and relieving otherwise injurious
inverse potentials on tube 3. In practice the
control of a recti?er system such as described is
The e?ect oi the resistance R-I2
'
Hence, by means of the potentiometer arm
PA, manually controlled potentials may be ap
plied to point T—S in governor circuit III to be
described. Once manually set, a given poten
tial is substantially constant... If arm PA is
turned to point T—IS, then T—9 will become
fully negative and all directly connected circuits
10 will be copiously supplied with negative elec
substantially as sensitive and as ?exible as if
both tubes such as 3 and 4 were grid-controlled.
Tubes l and 2 in section I-A are similar re
spectively to tubes 3 and 4 and are similarly
trons. If the arm PA is turned to the terminal
related in a parallel circuit as shown. In this
T—l'l, then all connected circuits will be rela
case the second component ST—2 of the anode
tively positive, being starved of negative electrons.
transformer AT connects between the anode of
Returning to the ?rst position of arm PA,
tube l and the brake control coil B and thence 15 namely T—IS, if the arm PA is placed at that
through a resistance R—B to the point 'I‘-—\4.
point, the cathode K—I of tube 5 becomes sub
The operation of this tube I in feeding direct
stantially fully negative (via W—5 including
current to the coil B, in connection with the
R—-9) , but the free flow of the negative current
plain recti?er tube 2 will be obvious in view of
is impeded by resistance R--!!. Relatively. the
the drawings and the above discussion in con 20 grid G—-3 of tube 5 will be positive, and the nega
nection with tubes 3 and 4. It will be noted
tive current will ?ow from cathode K--| to the
that any current ?owing through coil B also
respective anode of tube 5 and to line W—i2 con
?ows through resistance R-B.
nected therewith. The effect of this will be shown.
A reference voltage is established by means of
Tube 5 is heated by connections 2-2 to its cath
the circuit II about to be described. The purpose 2.5 ode from' a secondary component of trans
of this is to set a level of potential for controlling
the grids of tubes 3 and I ofv the principal rec-'
ti?er circuits I and I-A. It should be noted at
former F1‘.
Generator GN is used to feed the governing cir
cuit III in a proportion to generator speed, that
this point that the reference voltage may be
is, in proportion to the speed of the driven shaft
applied directly to the grids G-I and G-2 or, 30 SH (Fig. l). The proportion need not necessarily
as in the present example, indirectly through an
be a direct one but such is preferable. The circuit
ampli?er tube such as at 5. The reference volt
III is energized from generator GN through a
age circuit II originates in a secondary com
transformer TR. Basically the circuit ‘starts with
ponent RA of the transformer FI‘. Recti?ed
a ?ow of negative electrons from the cathode
negative current issues from the cathode K—3 35 K--4 of the tube 1 and passes through the sec
of tube 6, induced by the action of transformer
ondary T—8 of the transformer TR. (The cath
component RA. The cathode is heated by con
ode is heated over connections X—X from a sec
nections W—W from another secondary compo
ondary component of transformer FT.) From
nent of RA, as indicated. This sends current
transformer TR current passes through W—8, in
during one part of the cycle through point T—I 4, 40 cluding resistance R—l?, to the grid G--4 of tube
one leg of the transformer RA, line W—3 to
5. Return is effected through the cathode K—2
junction point T-I I. At this point the circuit
of tube 5, line W-—6, point T——-I2_. resistance
branches. One branch leads through a resistance
R—l4, point T-—-l I, point T—IB of the potenti
R-l4 to point T—IZ (by-passing a resistance
ometer’ PT, returning ?nally via arm PA, point
R-—-l3) and then via wire W--6 to cathode K—-2
T—9 and W—8l back to the cathode K—4 of tube
of ampli?er tube 5. The other branch leads to 3 1. A parallel part of this circuit may be traced
and through a potentiometer PT and thence ._ as follows: cathode K—4, to an anode of tube 1,
through line W—ll, point T—IO, resistance
point T—8 of transformer TR, W—8 resistance
R—I2, point T—l3, choke CH, line W-4 and
R-'-| I, point T—9, and back to the cathode K—-4
back to the cathode K—3, thus completing the 50 of tube 1 via W--8l. Suitable condensers C-2
circuit.
and C—3 parallel the resistances R-ll and
R-I 0 respectively.
The resistor combination R—l3, R—I4 is in
effect a voltage divider. The point T—IZ has a
Upon moving the potentiometer arm PA from
relatively negative potential which (according to
T-—|6 toward T—II, the clutch coil L, as will
the resistance values indicated on the drawings) . appear, is increasingly energized, thus tightening
is less than the full negative potential of point
the magnetic clutch coupling and causing the
T—I6 in the potentiometer PT. Thus the arm
driven shaft SH to increase in speed. This in
PA of the potentiometer PT can bring its con
creases the speed of the generator GN. At some
point the arm PA is brought to rest and under
tube 5) to a more negative value than wire W—B. 00 such conditions a de?nite potential will be ob
‘Tube 8 is a cold cathode tube. This con
tained, which bears a de?nite relation to the
stitutes an automatic resistance leak in circuit
potential which is obtained at point T—IB. Since
necting wires W--5 (connected to cathode K—-l of
I1’. and, due to its inherent characteristics, has
a function under certain conditions of causing
In the present
the potentials generated by the generator GN are
then below that set by the arm PA, the setting
of PA determines the speed to which the clutch
will accelerate its driven member and the gen
erator, a balance occurring ?nally as will appear.
Also, if at a given setting of arm PA, the mechani
cal load on the machine driven by the clutch C
is decreased, the shaft SH will accelerate. In
other words the speed ?xed by the energization of
case this holds the connected reference voltage
load coil L (at a greater load) will increase at
a relatively short circuit across certain poten
tials to which it may be connected. Thus, if the
voltage across the circuit of the tube 8 tends to
rise unduly above the circuit rating, the tube
becomes more conductive and relieves its con
nected circuit of enough current to suppress more‘
than an incipient voltage rise.
circuit II substantially steady at adjusted rat
the lower load. The generator GN will again
ing. Choke CH and condenser C—~l effect the
gain in voltage due to the speed increase.
usually desired ?ltering of the reference voltage 75 Cathode K-Z of tube,5\ operates at a ?xed
7
v2,411,122
8
negative potential because it is permanently con
nected to T—I2 through wire W-B. Its negative
recti?er circuit I and I—A. Its object is to
"tilt” or shift the operating potentials instan
potential is about 1.12 volts less negative than
taneously from grid G—| in tube 3 to grid (3-!
in tube I to accomplish transfer of operations be
the point T—IG; or, point T—l6 is 1.12 volts more
negative than T—l2. Thus, even taking the re On tween these two. To clarify it and its operation,
Fig. 8 has been drawn to emphasize the bridge re
sistors R-Hl and Ry-H into account, a relative
negative potential can be applied to the grid G-t
lationships. The reference characters corre
by turning arm PA to point T—IS. This makes
spond. Only those elements have been shown on
the grid G-4 1.12 volts more negative than cath
Fig. 3 which actually control the system, includ
ode K-2 and the tube 5 becomes entirely shut off. 10 ing the two components of tube 5 which are shown
for clarity in two separate units 5a and 5b. The
Whenever PA is moved clockwise toward T—ll,
the grid G-4 ?rst reaches zero potential with
electric bridge and related circuits are stripped
respect to cathode K—2 and then becomes rela
of all auxiliaries so as to permit relatively simple
tively positive. Thereupon grid G-? ?res cath
analysis of the fundamentals.
ode K—2 which supplies negative electrons to grid 15
From Fig. 3 it will be seen that a bridge is de
G--2 of the brake exciter tube I. This shuts off
?ned by three resistances R-C, R—'i, R-8 and
tube I and shuts off excitation of the brake coil B.
the element 5b of the tube 5. The impedance of
When cathode K—2 passes negative electrons
this element 5b supplies resistance.
to point T—5 a copious supply of these pass
A reference voltage (150 volts for example)
through resistor R-B to the point T—l 0 and then 20 from W—6 and W—H of circuit II is connected
back into the cathode K-3 of tube 6 via W-—-i I,
across the bridge at T—‘I and T—IB. If all of
R-lZ, T—lii, choke CH and W—li. Simultane
the sides of the bridge were to have the same re
ously the system T—5, T—l, R--3, T—2, W--'I,
sistance, the voltage drop from T—? to T-8
T—l5, W-l, K—-‘l ?lls with negative electrons
would be equal to one-half the total, and an equal
to the theoretical (static) potential of minus 140 25 drop would occur between T—‘i and T—5. How
volts as referred to T—IO, there being a loss of
ever, when the tube elements 5b are not oper
10 volts across tube 5 and R—-6. There is also a
ating they have practically an in?nite impedance
drop of 150 volts across R—8 and R,—l.. T—6,
so that, with the grid G-—il fully negative, the
being at half potential between that of the ends
voltage from T—5 to T—‘i is 150 volts, with no
of R—l and R—8, has a potential of minus '75 30 current ?owing through R-?.
I
volts with relation to T—li]. Hence T—5, being
Assuming a starting condition, with the arm
connected to grid G-i of tube 3 through resistor
PA‘ of the potentiometer PT on point T--l6, nega
R—i, is 75 volts plus compared to 140 volts minus
tive is supplied from T—i? through W-5, re
for cathode K-‘l. This makes grid G---! of tube
, sistance R-i i and to grid G—!i of tube elements
I positive to the cathode K—-l therein and tube 35 51). The grid G—4 becomes fully negative and
3 therefore ?res and energizes coil L.
the tube elements 51) become inoperative. The
The above goes on‘until the speed of the output
result is the stated potential of 150 volts across
shaft SH and the governor GN rises to a point
the cathode K-2 and anode of said tube elements
where the voltage of governor GN overbalances
56 in the bridge.
the voltage-set by the potentiometer PA.- That
In the meantime, however, tube elements 5a
is, when the voltage of the generator GN rises
pass current because the grid G——3 operates at
high enough upon building up of speed, su?icient
negative electrons will issue from the cathodes
KJll of the tube 7 and, by means of the wire W—B,
the grid G-Q of tube 5 will become more nega
tive than the T—9 potential, because the current
through the resistor R—! I will be reversed. Fur
thermore, the negative potential through wire
nearly full capacity at grid to cathode potential
between zero and minus two volts, due to the tube
characteristics. As a result negative electrons
leave the cathode K—l and pass through tube ele
ments 5a and enter the cathode K-—6 of brake
rectifying tube 5, the grid G~—2 of which is fully
positive (150 volts plus). Hence the tube I excites
W—B will dominate; causing the above-described
the brake coil B.
anode currents to, diminish or shut oil completely. 50
If the arm PA is turned clockwise, the potential
The negative electrons from point T—IZ will
of wire W—5, resistance R—l i and grid G-t, is
pass through wire W—-6 and wire W—9 and will
increased positively, so that the grid G-d becomes
again dominate at the grid G-I of tube 3 and
relatively positive and the tube elements 51: come
shut off this tube.
into action, or ?re. At the same time the cathode
At this timethe bridge system V coupled with
K-—I of tube elements 5a becomes more positive,
circuit IV operates so as to make the grad 6-2 of
making grid G-3 negative and stopping current
the brake rectifying tube I relatively positive,
?ow through the tube elements 5a. The tube
thus ?ring it and operating to energize the brake
elements 5b, when operating, having a lower 1m
coil B. Details will be described presently. As
pedance than resistance R—-8, results in drop of
shown, when the generator GN gains voltage it 00 the potential of point T—~5 to less than that of
shuts oil‘ tube 3 by action of grid G-l. Since
brake recti?er tube i at the operating conditions
the principal rectifying system I—A is similar in
under consideration so that (and this occurs pro
operating characteristics to the rectifying sys
gires'sively) the tube l reduces its brake excita
tem I, instead of applying full excitation to the
t on.
brake coil B, the'system tends to govern the brak
At the same time the drain by tube elements 5b
ing e?'ect exactly as described in connection with
will drop the potential from T—5 to T—‘i, for
the load coil L. This braking e?ect is maintained
example from 150 to 10 volts. Under balanced
until the machine is brought back to the original
conditions, the potential between T—6 and T—5 is
speed set by the potentiometer PA and, if the
75 volts, because the potential of T—5 is the same
speed then continues to 'drop further, the prin
as that of T—lll. Hence as between wires W—-l0
cipal recti?er circuit I will take over the function
and W-B (T—5 to T—~6) conditions change from
of governing through circuit I, the circuit I—A
say W—l0 at plus 150 volts and W—9 at plus
being again released.
'
{75 volts, to a condition wherein wire W-lt‘l is
The circuit V may be called a bridge transfer
plus 10 volts and wire W-9 is plus 75 volts, or rel
.gcircuit which operates in conjunction with the
atively, Wire W—9 is 65 Volts higher in potential
2,411,122
than wire W-lii. Since resistances R--3 and
R-l divide this voltage, point T—2 becomes 32.5
volts negative to T—3 and T—S. Therefore, grid
G—| in clutch tube 3 becomes positive in rela
tion to its cathode K-‘l and therefore tube 3
?res, thus energizing the clutch coil L. This
tightens the magnetic coupling with the output
shaft SH and accelerates the generator GN. As
the voltage of the generator GN builds up, nega
10
power, and in the other, no power except mag
netizing current.
Returning to more detailed operation of the
machine, starting from standstill a bias for com
plete shutoff of tube 3 must exist and is pro
vided thus: T—lll is fully positive in relation to
T—‘l (150 volts). T--6 is 75 volts positive to
T--l. The circuit R.—5, R.—4, 3-8 (a path for
the biasing circuit) when calculated for 150 volts
tive electrons originate at K—4 and pass to the 10 indicates that point T—Z is 117 'volts plus, and
T—3 is 94 volts plus. Hence, grid G~—l is nega
anode of the tube 1, through the secondary wind
tive by 23 volts to its cathode K--'| which is con
ing of the transformer TR, resistance Rr-IO and
nected to T—2I All this occurs under static con
to grid G-l of tube elements 5b. This tends to
ditions.‘ When tube section 5b operates, this con
make the grid G-l relatively negative and causes
tube elements 5b to diminish in activity. 'The 15 dition (statically considered) is reversed, so that
T—3 and G~—l become 32.5 volts positive to T--2
process continues, causing close regulation of the
and K—‘I, as above explained.
clutch output speed.
'
.
Actual conditions when governor GN oper
As above indicated, if the load on the clutch C
ates are such that tube section 5b, being con
becomes overrun or lost, the output shaft SH also
speeds up, causing the generator GN to charge 20 tinually modi?ed, the grid potential at G-l to
the grid G-l still more negatively, thus en
K—‘| of tube I may function with a a differ
tirely shutting off the tube elements 5b. This
ence of only 2 or 3 volts rather than the larger
returns the bridge circuit to the original condi
values stated.
tion wherein grid (3-2 of the brake rectifying
Now, again reconsidering the fact that the
tube 1 is positive and the brake thus becomes
basic bias at standstill is: T—3 to T—2, G-l to
energized. Under these conditions also, the
K—‘|, 23 volts negative, and such basic bias at
clutch rectifying tube 3 is shut off because point
running condition is T—3 to T—2, 32.5 volts posi
T—G becomes relatively negative to T--2, G-l
tive, nominally a difference of 55.5 volts. Since,
being negative to its cathode K--1, whereupon
as above explained, actual operating conditions
tube 3 is completely shut off. As soon as the 30 narrow this down, let us assume that this dif
brake BR is energized and on, the governor GN
ference is such as to reduce the voltage spread
governsthe braking effect because as speed falls
off the action is through tube |.
Thus it will be seen that the generator GN
governs and controls both the clutch coupling
and the brake action, that is, it controls both an
accelerating and a decelerating action. This
tends to maintain a closely constant speed of the
to 9.5 volts while running and governing. This
is the spread between the absolute values under
the static conditions. The basic variation each
side of zero is not even 23.5 negative to 32.5
volts positive. This requires that, on turning
the potentiometer PA toward a lower speed there
will not be an instantaneous transfer measured
output shaft SH regardless of either relatively
in degrees of movement of the potentiometer arm.
slight changes in load or radical changes in load, 40 For example, since all rheostats or potentiometers
including the entire removal of load. The sys
are crude, a very slight movement or imperfec
tem not only will apply the brake if the load
n tion of contact would cause the difficulty of in
shaft SH tends to increase in speed due to light
stantaneously applying the brake. However, by
ening of load, but also if the load shaft SH tends
means of the above uneven biasing, it becomes
to overrun and drive the eddy-current coupling
necessary to move the potentiometer at least
and brake. Under the latter condition the brake
enough to be equivalent to 5 or 10 R. P. M.
will apply suf?cient retarding force to regulate - change on the governor speed (and hence its
the overrunning or overdriving of the load so as
voltage) so that with ordinary operation only an
to maintain substantially the original speed as
intentional change on the part of the operator
50 will bring into action the braking effect.
set by means of the potentiometer PT.
The advantages of the invention do not ac
crue to prior systems in which a governor simply
tightened and loosened a magnetic slip coupling
between the driver and the driven load member.
This is because, for one thing, these old systems .
had no controlled means for retarding the driven
member which was responsive to governing. Ree
Tubesection 5a is ‘also used as a stabilizer of
action at very low driven speeds. When the speed
of the output shaft drops to low values, as say
10% of the maximum, in some uses the load may
be so light as to cause instability of regulation
by the governing circuit. In this case, it is de
' sirable for stabilization to apply the brake to add
a small brake load to the mechanical load. When
tardation simply was effected by the mechani-‘
cal load carried, and if this load were dropped,
the arm PA is turned to a low value, as at position
the friction might not be enough to slow down 60
25 in Fig. 3, the cathode K-l of section 50.,
the apparatus quickly enough. By means of the
reaches a potential at which tube section So. can
present invention the brake control action is ap
operate (a small negative difference between K-l
plied to decelerate, in addition to the decelera
and G-3 is required) so that this action occurs:
tion normally caused by a load. Thus under any
conditions speed control is much more prompt - Electrons issue from K-l, through the anode of '
section 5a, wire W-IZ to cathode K-B in tube I.
and close than heretofore.
Thus K-B becomes more negative than before as
By means of the invention the load at the
related to G-2 and T-5. This is the same as
output shaft of the clutch can be held closely
making G4 plus as regards K-B, so that tube
at a de?nite speed, regardless of whether the
driven machine loads the systems or attempts 70 l acts, applying a load.
As arm PA is turned more toward T-IG, this
to drive the system. In practice, the transition
effect increases. By this means, it is possible to
from driving the load, to retarding it, is sub
obtain a closely controlled speed reduction of say ’,
stantially imperceptible, except by means of an
60 to 1 on the output shaft of the eddy-current
ammeter in the A. C. induction motor leg, which
meter indicates that at one point the motor takes 75 clutch, producing a stable rotation at such low
2,411,122
\.
ll
12
speeds, and this action further can be controlled
manuallyby manipulating arm PA.
tion AD, EA may be cut off and the motoring
element EA, FM used to drive the engine E from
RT through the shafts SH and DS, the dynamom
\
Another feature is that every movement of the
arm PA to a lower speed position is itself accom
eter elements being under these conditions do;,
panied by a “braking effect thus accomplishing
automatically arapid deceieration. This is quite
energized.
Quite often engine testers want to know the
valuable on many ‘.Pl‘OdllClliOIi machines other
than the grinders ‘mentioned. Where machine
exact friction of.an engine which has been run
ning.for._;_some time at a ?xed load and speed and
inertias are large, this braking effect on the slow
at a given'temperature and lubricating conditions.
down may eil'ect substantial savings in time and 10 For
example, if an engine capable of a maximum
reduction of costs. For examplel “on one textile
speed of 2800 R. P. M. at 2000 H. P. has been
machine, the time for deceleration has been cut
operated at full speed for the period of an hour,
for rapid successive deceleration periods from
it is quite important to know de?nitely and as ‘
12% of the total operating time of 1.6%.
precisely as possible how much friction loss there
Exemplary electrical values of various circuit 15 is in the engine under the conditions of operation.
items appear on the'drawings. Exemplary com
If the engine can be cut out of power operation
mercial designations of the tubes above discussed
‘along with the dynamometer AD, and instantane
are as follows:
-
'
Designation
ously driven from the motor, then calculations
20
from the reaction torque on AD will give the fric
tion horsepower at the instant and under the
conditions existing at the time the engine was
fully loaded.
Referring to the diagram of Fig. 4 it is clear
that if coil B—I is energized and the engine E
25 is driving atv full load and full speed, it will be
quite valuable to be able to operate the motor RT
energization of the ?eld FD, and thus to
Another valuable application of the circuits ' without
prepare it for a quick test of friction horse power
herein disclosed is shown in Fig. 4. This has to
by changing from absorbing to motoring condi- '
do with the testing of internal combustion engines 3.0
tions.
Thus‘ the armature EA will be rotating
by means of a combination of absorbing and a
continuously during operation of the absorbing
motoring dynamometer apparatus. The absorb
dynamometer combination EA, AD; but no cou
ing and motoring elements of the machine may
pling
will exist between EA and the ?eld member
be in one or di?erent units but the former is in
FM‘. Then by employing an electronic control
dicated in Fig. 4. In Fig. 4, AD is a.- polar ?eld
such as here described, a single element in the
stator which rocks on trunnions if“ in a frame
hands
of the operator can m made to shut off the
6%. Resisting moments of this stator are ap
engine ignition and fuel and simultaneously cut
plied to a registering scale Hi5 by a torque arm
o?‘ excitation of coil 3-! while cutting in exci
Mil. The exciting ?eld is shown at B-i. The
of coil F-D, and then the motor MAC takes '
driven shaft in this case is again indexed SH. It 40 tation
over
the
function of driving the engine E at prac
rotates in stator AD and is driven from engine
tically' the same speed as'it was acting» under
E to be tested. Coupled on the same shaft SH
load. This involves the same problem as in the
within stator AD is an eddy-current armature
example above given, namely, that the system
EA. When ?eld B-i is energized a polar ?eld
becomes
suddenly unloaded, except for the fric_
from AD links B-I to set up magnetically reactive
tion horse power, under which conditions is de
eddy currents and heating in EA. Thus energy
sired a substantially instantaneously controlled
may be absorbed from E and measured at “15.
and
governed transfer between absorbing and mo
The heat may be carried o? in any of the usual‘
toring conditions. Thus coils BI and FD in Fig. 4
ways (not shown).
are the equivalents of coils B and L respectively in
Within armature EA is a polar ?eld member
Fig. 1, so far as the circuits of Figs. 2 and 3 are
FM on a drive shaft D8 which carries the rotor
concerned.
RT of an induction motor MAC. The ?eld coils
It should be understood that mechanically con
of FM are shown at FD. When FD is energized
sidered, some or all of the absorbing dynamom
a polar ?eld from FM links armature EA setting
eter elements shown in Fig. 4 may be separated
up reactive eddy currents therein. Thu; EA may . from the motoring dynamometer elements.
be driven by its electric slip coupling with FM.
In Fig. 5 is shown a scheme for reconnecting the
The ?eld FC of motor MAC is attached to stator
principal recti?er circuits I and I—A for further
AD. It is intended that the ?eld member FM
accelerating the transfer of excitation between
shall be driven at a constant speed from armature
coils L and B. Like numerals designate like parts.
RT, but that the armature EA be driven at any 60
This
alternative is particularly useful for use with
speed required of the shaft SH to drive the engine
apparatus such as shown and described in Fig. 4,
E. Thus when ?eld B-I is energized (FM dead),
wherein very quick transfer of excitation is desir
AD and EA constitute an absorbing dynamometer
able.
It consists in a resistor R connected to the
having in effect a brake action on EA.
I
.
two electrical loads L and B which are to be in
When FD is energized (B—-l dead) there is a
terchanged by the circuit. The object of this re
slip coupling between RT and EA. Since motor
sistance is to apply potential to the coils B and L
MAC has its stator supported in the inside of
which is higher than the normal rating of the
stator AD, driving may occur from the motor and
coils. This involves the dissipation of some of
the reaction torque due to driving measured at
what
otherwise be useful direct current, but
I05. This makes these elements a motoring 70 this iswould
not important in view of the advantages
dynamometer. With apparatus of this class it is
which accrue in transfer speed.
i
possible to load the engine E by means of the ab
For
example,
if
the
voltage
drop
across
either
sorbing dynamometer elements AD, EA when 3-!
L
or
B
is
80
volts,
as
indicated,
then
40
volts
is properly energized and motor RT is de
applied across resistance R will make 120 volts
energized. When desired the absorbing combina
total, either through B and R, or L and R. Usu
2,41 1,1212
-
14
l3
ally B and L can be made of the same resistance.
Assuming a current of two amperes through the
system of either B and R or L and R, it is clear
that before this current starts to flow, a poten
by the fact that in response to deviation of the
speed-of said driven member below said prede
termined value a driving force is applied through
tial of 120 volts is applied across L or B, as the
ber by tightening said clutch, the clutch being
deenergized when the brake is energized and
vice versa, clutch and brake tightening being in
case may be. This abnormally high potential re
duces the time constant of coil L or B so that
the magnetization time is considerably reduced.
Thus it will be seen that the loading resistance R
the clutch from the driving to the driven mem
a proportion to the said respective speed devia
tions.
becomes a means for hastening full magnetization 10
4. In apparatus of the class described, a driv
after load transfer has occurred.
ing member, a driven member, an electromag
In the example shown in Fig. 5, the entire re
sistance of one load L and R (for example) is 60
netic slip clutch between the driving member and
the driven member, an electromagnetic brake
associated with the driven member, electronic
ohms with 40 ohms in L and 20 ohms in R. With
120 volts applied two amperes will flow. The 15 means responsive to the speed of the driven
, watts lost in coil L will be 160 and in resistance
member for controlling the clutch and the brake,
B it will be 80. This loss is functionally compen
characterized by the fact that when the driven
sated for by the accelerated transfer.
member incipiently deviates above a predeter
In the following claims the term “brake” is
mined speed a retarding force is applied to the
intended to describe any apparatus having a re 20 driven member by tightening said brake, and by
sisting or drag e?ect on a controlled member and
the fact that in response to deviation of the speed
includes devices such as the dynamometer ele
of said driven member below said predetermined
ments AD and 3-4 of Fig. 4, as well as elements
value a driving force is applied through the
such as BR and B in Fig. 1.
clutch from the driving to the driven member
In view of the above, it will be seen that the
by tightening said clutch, the clutch being de
several objects of the invention are achieved and
energized when the brake is energized and vice
other advantageous results attained.
versa and means for maintaining some brake en
As many changes could be made in the above
ergization while the clutch is energized at sub
constructions without departing from the scope
stantially high speed reductions through the
of the invention, it is intended that all matter 30 clutch.
contained in the above description or shown in
5. In apparatus of the class described, a driv
the accompanying drawings shall be interpreted
ing member, a driven member, an electromag
as illustrative and not in a limiting sense.
netic slip clutch between the driving member and
I claim:
the driven member, an electromagnetic brake
1. In apparatus of the class described, a driv
associated with the driven member, electronic
ing member, a driven member, an electrical driv
means automatically responsive to the speed of
ing coupling therebetween, an electrical brake
the driven member for controlling the clutch
on the driven member, a generator driven by the
and the brake, characterized by the fact that
driven member, an electronic circuit controlled
when the driven member incipiently deviates
from said generator and adapted to tighten said
below a predetermined speed a driving force is
electrical driving coupling in response to certain
applied through the clutch from the driving to
lower speeds of the driven member, and adapted
the driven member by tightening said clutch, and
to energize said brake in response to certain
in response to deviation of the speed of said driv
higher speeds of said driven member and auto
en member above said predetermined value ap
matic means in said circuit for preventing sud 45 plying a retarding force to the driven member
den changes in the application of energy through
by energizing said brake, the clutch being de
either said clutch or brake.
energized when the brake is energized and vice
2. In apparatus of the class described, a driv
versa, and manually control means in said circuit
for determining said predetermined speed.
ing member, a driven member, an electromag
netic slip clutch between the driving member and 50
6. In apparatus of the class described, a driv
the driven member including a clutch ?eld coil,
ing member, a driven member, means for apply
an electromagnetic brake associated with the
ing a driving force from the driving member to
driven member including a brake ?eld coil, elec
the driven member, means for applying a retard
tronic means responsive to the speed of the
ing force to the driven member, means responsive
driven member for automatically controlling the
to acceleration and deceleration of the driven
clutch and the brake operations to maintain the
member above and below an optimum speed of
speed of the driven member substantially con
the driven member for alternating said applica
tions respectively to the means for applying the
stant, characterized by the fact that when the
driven member incipiently decelerates from a
driving force and to the means for applying the
predetermined speed, the clutch coil is’ energized
retarding force, means for eifecting gradual ap
and the brake coil is deenergized, and by the fact
plication of one or the other of said forces, vari
that when the driven member incipiently accele
rates from said speed the brake coil is energized
and the clutch coil is deenergized.
3. In apparatus of the class described, a driv
ing member, a driven member, an electromag
able means for changing said optimum speed and
means responsive to substantially large ratios of
speed drop between the driving and driven mem
bers for applying the retarding force while the
driving force is eifective.
7. In apparatus of the class described, a driv
ing member, a driven member, electromagnetic
netic slip clutch between the driving member
and the driven member, an electromagnetic
means including a ?rst ?eld coil energizing a
brake associated with the driven member, elec
tronic means responsive to the speed of the 70 driving slip coupling between the driving and the
driven member for controlling the clutch and the
driven members, electromagnetic means com
prising a second ?eld coil energizing means tend
brake, characterized by the fact that when the
ing to brake the driven member, recti?er tubes
driven member incipiently deviates above a pre
each having a cathode, an anode and a grid, the
determined speed a retarding force is applied to
the driven member by tightening said brake and 75 tubes being connected each respectively to feed
2,411,122
,
15
16
one of said coils, and means responsive to the
speed of the driven member and controlling said
grids alternatively to ?re the tube connected with
the ?rst coil upon incipient drop of speed below
control said optimum speed, and means whereby
said respective energizations of the clutch and
prising a second ?eld coil energizing means tend
controlled, recti?erv circuits through said tubes
brake'coils in response to speed changes are op
erative whether said incipient changes are in
a, normal speed of the driven member or to ?re
duced by actuation of said manual control or
the tube connected with the second coil upon in
changes in load on the driven member.
cipient speed increase above said normal speed
11. In apparatus of the class described, a driv
of the driven member.
.
ing member‘, a driven member, an electric slip
8. In apparatus of the class described, a driv
clutch coupling said members, an electric brake
ing member, a driven member, electromagnetic 10 operative on the driven member, an energizing
means including a ?rst ?eld coil energizing a
clutch coil in the clutch and an energizing brake
driving slip coupling between the driving and
coil in the brake, a brake coil recti?er tube, a
the driven members, electromagnetic means com
clutch coil recti?er tube, said tubes being grid
ing to brake the driven member, recti?er tubes 15 and feeding said coils respectively, a generator
each having a cathode, an anode and a grid, the
driven by said driven member, a governing cir
tubes being connected each respectively to feed
cuit under control of said generator, a reference
one of said coils, means responsive to the speed
voltage circuit coupled with said governing cir
of the driven member and controlling said grids
cuit,
control means for predetermining the ref
alternatively to ?re the tube connected with the 20 erence voltage in said reference voltage circuit.
?rst coil upon incipient drop of speed below a
a transfer circuit connecting said reference volt
normal speed of the driven member or to ?re
age and governing circuits with the grids of said
the tube connected with the second coil upon
tubes, said transfer circuit being capable alterna
incipient speed increase above said normal speed
‘ tively of ?ring one tube while stopping the other,
of the driven member, and means whereby the 25 said transfer circuit being operative in connection
current passed upon ?ring of either tube is varied
with the governing and control circuits to ?re the
with varying incipient speed changes so as to
brake coil in response to incipient speed change
inhibit said changes according to their magni
of said generator above an optimum as ?xed by
tildes.
said manual control means, and to energize the
9. In apparatus of the class described, a driv 30 clutch coil in response to speed change of said
ing member, a driven member, an electromag
generator below said optimum.
netic slip coupling between the driving and driven
12, In apparatus of the class described, a driv
members, a ?rst ?eld coil in the slip coupling, an
ing member, a driven member, an electric slip
electromagnetic brake operating upon the driven
clutch coupling said members, an electric brake
member, a second ?eld coil in the brake, a con 35 operative on the driven‘ member, an energizing
trol generator driven by the driven member, a
clutch coil in the clutch and an energizing brake
governing voltage circuit supplied from said gen
coil in the brake, a brake coil recti?er tube, a
erator in accordance with the speed of said driven
clutch coil recti?er tube, said tubes being grid
elements, a reference voltage circuit connected
recti?er circuits through said tubes
with said governing circuit, a circuit for alter 40 controlled,
and feeding said coils respectively, a generator
nately energizing said coils, a voltage tilting
driven by said driven member, a governing cir-'
bridge circuit connecting said governing and
cuit under control of said generator. a reference '
reference voltage circuits with said energizing cir
voltage circuit coupled with said governing cir
cuit and adapted in response to generator speeds
cuit, control means for predetermining the ref
below a predetermined value to cause energiza
erence voltage in said reference voltage circuit,
. tion of the ?rst coil with deenergization of the
transfer circuit connecting said reference volt
second coil, and at higher speeds of the generator . aage
and governing circuits with the grids of said
above said predetermined value to cause deener
tubes,
said transfer circuit being capable alter
gization of the ?rst coil and energization of the
natively of ?ring one tube while stopping the
brake coil, and circuit means whereby the action 60 other, said transfer circuit being operative in
of said governing circuit continuously proportions
connection with the governing and control cir
current through either of said coils when ener
cuits to ?re the brake coil in response to incip
gized respectively.
ient speed change of said generator above an
10. In apparatus of the class described, a driv
optimum as ?xed by said manual control means,
ing member, a driven member, an electromag
and to energize the clutch coil in response to
netic slip clutch between said members having
speed change of said generator below said opti
therein a clutch coil, an electromagnetic brake
mum, and means whereby the current passed
means cooperating with the driven member and
through either of said tubes while ?ring varies
having therein a brake coil, a generator driven
uninterruptedly with the generator speed devi
by the driven member, a governing circuit ener 60 ation from said optimum. ,
gized by said generator, a manually controlled
13. In apparatus of the class described, a driv
reference voltage circuit, circuit means for ener
ing member, a driven member, an electric slip
gizing said clutch and brake coils, and a transfer
clutch coupling said members, an electric brake
circuit connecting said reference and governing
operative on the driven member, an energizing
circuits with the energizing circuit so that incip 65 clutch coil in the clutch and an energizing brake
ient changes in speed of the driven member above
coil in the brake, a brake coil recti?er tube, a
an optimum will cause complete deenergization
clutch coil recti?er tube, said tubes being grid
of the clutch coil and progressive energization of
controlled,
recti?er circuits through said tubes
the brake coil in a proportion to the degree of
and feeding said coils respectively, a generator
speed increase, and whereby incipient reduction 70 driven by said driven member, a governing cir
in speed below said optimum will cause complete
cuit under control of said generator, a reference
deenergization in the brake coil and progressive
voltage circuit coupled with said governing cir
energization of the clutch coil in a proportion to
cuit, control means for predetermining the refer
the degree of speed decrease, manual adjustment
ence voltage in said reference voltage circuit, a
of said reference voltage circuit being adapted to 75 transfer circuit connecting said reference volt
17
2,411,122
age and governing circuits with the grids of said .
tubes, said transfer circuit being capable alter
.
18
tions responsive to incipient generator speed
deviations from an optimum value determined
natively of ?ring one tube while stopping the
by adjustment of the reference voltage cir
other, said transfer circuit being operative in
cuit, said transfer section effecting controlled
connection with the governing and control cir
transfer of energization from one to another of
cuits to fire the brake coil in response to incipient
said coils and vice versa depending upon whether
speed change of said generator above an optimum
said generator incipient speed deviation is above
as ?xed by said manual control means, and to
or below said optimum, and means operative at
energize the clutch coil in response to speed
relatively low adjusted optimum speed of the
change of said generator below said optimum, 10 driven member adapted to maintain some ener
means whereby the current passed through either
gization of the ‘brake coil under controlled ener
of said tubes while‘ ?ring varies uninterruptedly
gization conditions in the clutch coil.
with the generator speed deviation from opti
17. In apparatus of the class described, a driv
mum, and means for continuously passing cur
ing member, a driven member, an electromagnetic
rent through the tube supplying the brake coil 15 accelerating coupling between said members hav
to apply an arti?cial load to the driven member
ing a coupler ?eld coil therein, an electromagnetic
at certain substantially large speed reductions
brake associated with a driven member having a
between the driving and driven members.
brake ?eld coil therein, a first grid-controlled tube
14. In apparatus of the class described, a ‘driv
feeding the coupler coil, a second grid-controlled
ing member, a driven member, an electromag
tube feeding the brake coil, a reference voltage
netic clutch between the driving and driven
circuit, a governing circuit connected with said
members having a clutch ?eld coil, an electro
reference voltage circuit, a generator responsive
magnetic brake associated with the driven mem
to the motion of the driven member and feeding
ber having a, brake ?eld coil, a generator driven
said governing circuit, a transfer circuit connect
by said driven member, an electronic circuit hav 25 ing said reference voltage and governing circuits
ing a controlled recti?er section connected to
with the grids of said tubes and responsive to in
feed said coils alternatively, an adjustable refer
creased potential above a predetermined value in
ence voltage section, and a. governing section
the governing circuit to affect the grid of the
supplied ‘by the output of said generator, an ad
clutch coil tube to shut off‘ current therethrough
justable potentiometer connection between the 30 and responsive to decreased potentials in said
reference and governing sections, said electronic
governing circuit below said predetermined value
circuit having a transfer section responsive to
to affect the grid of the brake coil tube to shut off
voltage changes in the governing section caused
current therethrough, and means in said transfer
by‘ incipient speed deviations of the generator
circuit for controlling the relative voltage of the
grid of whichever of said tubes is carrying cur
from a predetermined value as determined by
the reference section of the circuit for control
rent, the last-named voltage control being in re
sponse to voltage changes in the governing circuit
ling the recti?er section to transfer energization
from one to another of said coils and vice versa.
brought about by deviation of the governor speed
from that which produces said predetermined
15. In apparatus of the class described, a driv
ing member, a driven member, an electromag 40 value of potential in the governing circuit.
netic clutch between the driving and driven
18. In apparatus of the class described, a driven
member, driving means therefor including an
members having a clutch ?eld coil, an electro
electrical eddy-current coupling, a ?eld coil for
magnetic brake associated with the driven mem
the coupling adapted to be energized to effect
ber having a brake ?eld coil, a generator driven
by said driven member, an electronic circuit 454 driving and'deenergized to reduce driving, eddy
having a controlled recti?er section connected
current drag means associated with the driven
to feed said coils alternatively, an adjustable
member, a second ?eld coil in the eddy-current
drag means adapted to be energized to effect a
reference voltage section, and a governing sec
tion supplied by the output of said generator, an
resistance‘ to the motion of the driven member
adjustable potentiometer connection between the 50 and deenergized to reduce resistance, an elec
tronic circuit connected to said coils and arranged
reference and governing sections, said electronic
circuit having a transfer section responsive to
for alternatively energizing them, and a generator
voltage changes in the governing section caused
driven by said driven member and adapted to con
by incipient speed deviations of the generator
trol said circuit according to the speed of the
from a predetermined value as determined by 55 driven member.
the reference section of the circuit, for control
19. In apparatus of the class described, a driven
ling the recti?er section to transfer energization
member, driving means therefor including an
from one to another of said coils and vice versa,
electrical eddy-current coupling having an eddy
said transfer section being also adapted in re
current member, a ?eld coil for the coupling
sponse to operation of said governing section to 60 adapted to be energized to effect driving and to
proportion the current in whichever part of the
be deenergized to reduce driving, eddy-current
recti?er section is operative at a given time, said
brake means associated with said driven member,
proportioning being in accordance with the speed
the eddy-current member of which brake means
of the generator.
is also said eddy-current member of the eddy
16. In apparatus of the class described, a driv 65, current coupling, the eddy currents due to both
coupling and braking occurring in a common por
ing member, a driven member, an electromag
netic clutch between the driving and driven
tion of said eddy-current member, a second ?eld
members having a clutch‘ ?eld coil, an electro
coil in the eddy-current brake means adapted to
magnetic brake associated with the driven mem
be energized to effect a resistance to motion of
ber having a, brake ?eld coil, a generator driven 70 the driven member and to be deenergized to re
by said driven member, an electronic circuit hav
duce resistance, and an electrical control circuit
ing a governing section fed by the generator and
connected to said coils and arranged for alter
having a connected adjustable reference voltage
natively energizing them.
section, and also having a transfer section con
20. In apparatus of the class described, a driven
nected to the governor and reference voltage sec 75 member, driving means therefor including an
2,411,122
I
19
'
electrical eddy-current coupling having an eddy
current member, a. ?eld coil for the coupling
adapted to be energized to e?ect driving and to
be deenergized to reduce driving, eddy-current
brake means associated with said driven member,
the eddy-current member of which brake means
is also said eddy-current member of the eddy
current‘ coupling‘ the eddy currents due to both
coupling and braking occurring in a. common por
tion of said eddy-current member, a second ?eld 1°
20
coil in the eddy-current brake means adapted to
be energized to e?ect a resistance to motion of
the driven member and to be deenergized to re
duce resistance, an electrical control circuit con
nected to said coils and arranged for alternatively
energizing them, and means driven by said driven
member and adapted to control said circuit ac
cording to the speed of the driven member.
ANTHONY WINTHBIR.
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