Electric torque converter

An electric torque converter arranged between a driving and a driven system onsists of an alternating current generator G which is connected to a dc motor M via a plurality of circuits C, D, Ko, which operate in parallel to each other.

BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION 
The present invention relates to an electric torque converter which is 
arranged between a driving and a driven system. 
In many drive systems, particularly those having internal combustion 
engines, the drive source supplies high power with good efficiency only 
within a narrow range and generally at high speeds of rotation. On the 
other hand, the driven system may often require the application of high 
power at very different speeds of rotation depending on the operating 
conditions. 
While mechanical gear shifts permit a step-wise conversion of the torque, 
the number of steps is limited by convenience in operation and the high 
expense inherent therein. Infinitely variable mechanical gear shifts are 
limited to relatively low transferrable powers. 
Hydraulic torque converters operate with infinite variation and also make 
it possible to operate the drive source within the optimal range of speeds 
of rotation. However, their efficiency is satisfactory only within a 
rather narrow transmission range, so that they frequently must be combined 
with mechanical gear shifts. 
There have also been attempts to use electrical machines for speedmatching 
and torque conversion. These systems can be classified in different 
groups. 
The known systems utilize the fact that the speed and torque of an 
electrical machine can be regulated via the magnetic field applied to the 
machine. These systems include generator-motor combinations in which the 
field of one or both machines is so regulated via resistors, additional 
excitation machines or current regulators that the torque or the speed of 
rotation can be adapted to the operating condition of the driven system. 
By the use of power electronics, torque regulation has been displaced by 
torque controls or speed controls. The known arrangements accordingly 
always contain electronic control circuits and/or microprocessors or 
process control computers. These known systems control either the field of 
the machines or the current, voltage or frequency of the electrical energy 
applied to the machine. 
Perhaps the best systems are homopolar machines which usually provide good 
properties for torque conversion. However, these systems disadvantageously 
require very high currents which occur with low voltages and must be 
conducted over slip rings or the like. Additionally, they require control 
or regulation of the torque. 
The object of the present invention is to provide an electric torque 
converter which, with high overall efficiency without the use of 
components which inherently produce a loss, has a linear speed/torque 
characteristic even at a motor speed of zero. 
Using the solution of the present invention, a change in the driven speed 
at optimal drive speed is possible without employing a control device, the 
power which may be transmitted having a wide maximum and remaining 
practically constant. 
West German Unexamined Application for Patent No. OS 14 38 811 discloses a 
circuit in which an asynchronous generator attached to a turbine is 
connected via capacitors and rectifiers and a starting resistor to 
propulsion motors (dc motors). But that case is concerned with a pure 
starting circuit for a turbine which operates at a constant speed of 
rotation. In that circuit, a starting resistor for the series motors 
cannot be dispensed with, while the capacitors serve exclusively to 
compensate for stray resistances. 
On the other hand, the generator of the invention produces an approximately 
delta-shaped alternating voltage, the dc motor is externally excited or 
excited by permanent magnet, and the capacitors limit the current to a 
permissible value, even at a motor speed of zero. Furthermore, in the case 
of the present invention, an additional control of the "transmission 
ratio" can be provided but, contrary to known proposals, this is not for 
the purpose of adapting the driven rotational speed at each moment to be 
as constant as possible relative to the speed of rotation of the drive, 
but serves exclusively for the overall optimizing of the total power which 
can be transmitted. 
The solution in accordance with the present invention, furthermore, has a 
low power loss which increases essentially with the power to be 
transmitted and decreases with an increase in the driven speed. 
One advantageous embodiment of the subject matter of the invention resides 
in the fact that the conductors of the generator winding are arranged in 
triangular shape on the outer surface of a stationary cylinder which can 
dip into the air gap of a pole wheel which is provided with a permanent 
magnet. 
For the adjustment of small machines, West German Pat. No. 939,463 
discloses an arrangement wherein a rotor with a self-supporting winding in 
an air gap is located between a permanent-magnet core and a return ring 
which is fastened by screws. 
West German Unexamined Application for Patent No. OS 21 01 459 also 
discloses a dc motor in which operation in different speed stages (change 
in transmission ratio) is possible by the connecting and disconnecting of 
parts of the armature winding. 
The present invention can be used to particular advantage in automotive 
vehicles since the electrical converter can replace not only the change 
gearing but also the clutch means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The function of the electric torque converter is based on the combining, 
pursuant to the invention, of a generator G with a dc motor M, both of 
which will be described in detail below, via a circuit consisting of a 
capacitor C and two diodes D.sup.+ and D.sup.- (FIG. 1a). 
The special generator G produces a triangle-shaped voltage (FIG. 1b), 
defined by the following equations: 
EQU u.sub.1 (t)=U.sub.1 .multidot.(1-4t/.DELTA.T) for 
O.ltoreq.t.ltoreq..DELTA.T/2 (Eq. 1a) 
EQU u.sub.1 (t)=-U.sub.1 .multidot.(1-4t/.DELTA.T) for 
.DELTA.T/2.ltoreq.t.ltoreq..DELTA.T (Eq. 1b) 
in which T=1/N.sub.1 is the time for one revolution at the speed of 
rotation N.sub.1, while .DELTA.T=T/n is the time within which the 
generator G having n pairs of poles turns past exactly one pair of poles. 
The peak voltage U.sub.1 =k.sub.1 N.sub.1 is to be proportional to the 
speed of rotation N.sub.1 of the generator G, and the direct voltage 
U.sub.2 =k.sub.2 N.sub.2 is to be proportional to the sped of rotation 
N.sub.2 of the motor M. The special construction of the motor M resides in 
the fact that it is fed via two independent windings W.sub.2.sup.+ and 
W.sub.2.sup.- on which the countervoltage U.sub.2 of opposite polarity is 
present. For the sake of clarity of the drawing, commutating means of the 
dc motor M as well as means for producing the magnetic fields at G and M 
have not been shown in FIG. 1a. 
In FIG. 2a, at the time t=0, u.sub.1 (t)=U.sub.1 is at the positive peak 
value and the capacitor C is charged via the diode D.sup.+ to the voltage 
u.sub.c =U.sub.1 -U.sub.2. Upon a drop in voltage u.sub.1 (t), there is 
also a drop in u.sub.p (t) (see FIG. 1a) and it becomes more negative than 
+U.sub.2, but until the time t.sub.e, it remains more positive than 
-U.sub.2, i.e. both diodes D.sup.+, D.sup.- are blocked. Only when the 
voltage u.sub.p tends to drop below -U.sub.2 at t&gt;t.sub.e will the diode 
D.sup.- become conductive and hold u.sub.p at -U.sub.2. Since u.sub.1 (t) 
continues to drop until t=.DELTA.T/2, the capacitor C will, from the time 
t.sub.e on, be charged via the diode D.sup.- to the opposite, equally 
large voltage u.sub.c =-U.sub.1 +U.sub.2. At t=.DELTA.T/2, this process is 
at an end and u.sub.1 (t) begins to increase again. Thus, u.sub.p (t) also 
increases and becomes more positive than -U.sub.2 but, until 
t=.DELTA.T/2+t.sub.e, more negative than U.sub.2, i.e. both diodes 
D.sup.+, D.sup.- are blocked. Only when t.sub.p becomes more positive than 
U.sub.2 does D.sup.+ conduct and charge C again to u.sub.c =U.sub.1 
-U.sub.2. 
This process now repeats itself periodically, the winding W.sub.2.sup.+ and 
W.sub.2.sup.- of the dc motor M being traversed alternately by the 
charge-change current i(t) of the capacitor C. This current has the value: 
EQU i(t)=C.multidot.du.sub.c (t)/dt=C.multidot.(du.sub.1 (t)/dt-du.sub.p 
(t)/dt) (Eq. 2) 
and can now be described section-wise for the above-mentioned time phases. 
If one considers D.sup.+ and D.sup.- as ideal diodes with forward voltage 
u.sub.d =0 and the voltage of the generator G as ideal triangular voltage, 
then from Eqs. 1 and 2 one obtains: 
EQU for O.ltoreq.t.ltoreq.t.sub.e : D.sup.+ and D.sup.- are blocked and i(t)=0 
(Eq. 3a) 
EQU for t.sub.e .ltoreq.t.ltoreq..DELTA.T/2: u.sub.c (t)=u.sub.1 (t)+U.sub.2 
and i(t)=-4C.multidot.U.sub.1 /.DELTA.T (Eq. 3b) 
EQU .DELTA.T/2.ltoreq.t.ltoreq.t.sub.e +.DELTA.T/2: D.sup.+ and D.sup.- are 
blocked and i(t)=0 (Eq. 3c) 
EQU for t.sub.e +.DELTA.T/2.ltoreq.t.ltoreq..DELTA.T: u.sub.c (t)=u.sub.1 
(t)-U.sub.2 and i(t)=4C.multidot.U.sub.1 /.DELTA.T (Eq. 3d) 
Thus, due to the triangular shape of u.sub.1 (t), the current curve is an 
alternatively positive and negative square curve as shown in FIG. 2b. In 
this connection, the positive current flows through the winding 
W.sub.2.sup.+ and the negative current through the winding W.sub.2.sup.- 
of the motor M so that the motor is driven in the same direction by both 
currents. Since during the blocking phases the voltage u.sub.p (t) changes 
with the same slope as u.sub.1 (t), we also have, as shown in FIG. 2a: 
EQU t.sub.e /2U.sub.2 =.DELTA.T/4U.sub.1 or t.sub.e 
=(.DELTA.T/2).multidot.(U.sub.2 /U.sub.1) (Eq. 4) 
i.e. the current flow time .DELTA.T/2-(.DELTA.T/2).multidot.(U.sub.2 
/U.sub.1) decreases with increasing voltage U.sub.2 =k.sub.2 N.sub.2 and, 
therefore, with increasing driven speed N.sub.2. 
Now it can be shown how the torque-speed dependence of the combination in 
accordance with the invention comes about. For this purpose, first of all, 
the work .DELTA.W.sub.2 absorbed by the motor M during a period .DELTA.T 
of the delta voltage will be calculated. During the first half-period 
0.ltoreq.t.ltoreq..DELTA.T/2, a constant (see Eq. 3) current i(t) with 
constant voltage -U.sub.2 flows for the time (.DELTA.T/2-t.sub.e) through 
winding W.sub.2.sup.-. During the second half-period 
.DELTA.T/2.ltoreq.t.ltoreq..DELTA.T, for the same time an opposite equally 
large current i(t) flows with opposite equal voltage +U.sub.2 so that the 
motor M takes up the same energy during both half-periods, i.e. 
##EQU1## 
Since this energy is removed in each period .DELTA.T, one can determine 
therefrom the power P.sub.2 =.DELTA.W.sub.2 /.DELTA.T and thus also the 
torque M.sub.2 =P.sub.2 /(2.pi..multidot.N.sub.2) and one obtains, with 
U.sub.1 k.sub.1 N.sub.1, U.sub.2 =k.sub.2 N.sub.2 and .DELTA.T=1/(N.sub.1 
n): 
EQU P.sub.2 =(4C.multidot.U.sub.2 .multidot.(U.sub.1 -U.sub.2))/.DELTA.T or 
(Eq. 6a) 
EQU P.sub.2 =(4k.sub.2 .multidot.n.multidot.C).multidot.N.sub.1 
.multidot.N.sub.2 .multidot.(k.sub.1 N.sub.1 -k.sub.2 N.sub.2) (Eq. 6b) 
EQU M.sub.2 =(2k.sub.2 .multidot.n.multidot.C/.pi.).multidot.N.sub.1 /(k.sub.1 
N.sub.1 -k.sub.2 N.sub.2) (Eq. 7) 
Since these relationships have been calculated for a combination of ideal 
generator G with ideal motor M with the use of ideal diodes D and an ideal 
capacitor C, no ohmic resistances determine the function in this 
calculation. Accordingly, in the ideal case, no energy is lost and the 
power P.sub.1 given off by the generator G must be equal to the power 
P.sub.2 absorbed by the motor M (Eq. 6). Since the torque of the generator 
G is M.sub.1 =P.sub.1 /(2.pi..multidot.N.sub.1), therefore, one obtains: 
EQU P.sub.1 =(4k.sub.2 .multidot.n.multidot.C).about.N.sub.1 .multidot.N.sub.2 
.multidot.(k.sub.1 N.sub.1 -k.sub.2 N.sub.2)=P.sub.2 =P (Eq. 8) 
EQU M.sub.1 =(2k.sub.2 .multidot.n.multidot.C/.pi.).multidot.N.sub.2 
.multidot.(k.sub.1 N.sub.1 -k.sub.2 N.sub.2) and (Eq. 9) 
EQU M.sub.2 /M.sub.1 =N.sub.1 /N.sub.2 (Eq. 10) 
The relationship in Eq. 10 shows the torque converter behavior of the 
arrangement in accordance with the invention. The driven torque M.sub.2 
for a driven speed N.sub.2 =0 appears initially to become infinite. From 
Eq. 7 and FIG. 3, it is seen that M.sub.2 (N.sub.2) drops linearly, 
starting from a maximum value at N.sub.2 =0. This finite value of M.sub.2, 
however, becomes understandable if one bears in mind that the torque 
M.sub.1 at the generator G (Eq. 9) also becomes zero for N.sub.2 =0. Thus, 
a maximum torque M.sub.2 can be maintained on the driven side with the 
speed of rotation N.sub.2 =0, in which connection we have P.sub.2 =P.sub.1 
=M.sub.1 =0. The optimum power transfer between drive side and driven side 
takes place with a speed ratio with which the derivative dP/dN.sub.2 
equals 0 and, therefore, with 
EQU dP/dN.sub.2 =k.sub.1 N.sub.1 -2k.sub.2 N.sub.2 =0; N.sub.2 /N.sub.1 
=k.sub.1 /2k.sub.2 (Eq. 11) 
or with the speed ratio at which U.sub.1 =k.sub.1 N.sub.1 is just twice as 
great at U.sub.2 =k.sub.2 N.sub.2. The driven torque M.sub.2 and the power 
P drop finally to zero when N.sub.2 reaches the value where N.sub.2 
k.sub.2 equals N.sub.1 k.sub.1, i.e. where U.sub.2 becomes equal to 
U.sub.1 (FIG. 3). 
Eqs. 6 to 11 completely describe the behavior of the electric torque 
converter. In the following, it will now only be explained why, with the 
driven speed N.sub.2 =0, a torque M.sub.2 =(2k.sub.2 
.multidot.n.multidot.C/.pi.).multidot.N.sub.1 is maintained (Eq. 7) 
without require torque (Eq. 9) or power (Eq. 8) at the generator G. 
With N.sub.2 =0, we have U.sub.2 =N.sub.2 k.sub.2 =0 and thus t.sub.e 
=(.DELTA.T/2).multidot.(U.sub.2 /U.sub.1)=0, i.e. the current pulses each 
reach a maximum width of .DELTA.T/2; i(t) does not produce any power at 
the motor M with U.sub.2 =0 and hence P.sub.2 =0. However, the voltage 
u.sub.1 (t) at the generator G lies at values between -U.sub.1 and 
+U.sub.1 so that the instantaneous power P.sub.1 (t) is definitely not 0. 
The power given off vanishes over each half-period .DELTA.T/2 of the delta 
voltage u.sub.1 (t) since, although during this time the current i(t) is 
constant, the voltage u.sub.1 (t), however, has equal positive and 
negative values. The current I, therefore, drives the generator G from t=0 
to t=.DELTA.T/4 and from t=.DELTA.T/2 to t=3.DELTA.T/4, while it brakes it 
during the intermediate time phases. 
This change remains in existence also upon an increase in speed of rotation 
N.sub.2 with decreasing ratio t.sub.a /t.sub.b between drive time and 
brake time (FIG. 2a) until N.sub.2 has reached a value such that N.sub.2 
.multidot.k.sub.2 =N.sub.1 .multidot.K.sub.1 /2, i.e. until U.sub.2 equals 
U.sub.1 /2. Of course, the power in Eq. 8 can now also be calculated 
directly, and with Eq. 1 and Eq. 3 one obtains 
##EQU2## 
EQU P.sub.1 =.DELTA.W.sub.1 /.DELTA.T=4C.multidot.U.sub.2 .multidot.(U.sub.1 
-U.sub.2)/.DELTA.T (Eq. 13) 
i.e. the power P.sub.1 produced by the generator G is equal to the power 
P.sub.1 consumed in the motor M, as can be noted from a comparison of Eq. 
13 with Eq. 6a. 
FIG. 3 shows how, with constant drive speed N.sub.1 and with fixed k.sub.2, 
the speed N.sub.2 can establish itself at the driven end depending on the 
torque requirement. Although the electric torque converter operates with 
good efficiency throughout the entire range, the maximum power is 
transmitted only in the vicinity of K.sub.2 N.sub.2 =k.sub.1 N.sub.1 /2. 
By varying k.sub.2 during the operation, the product k.sub.2 N.sub.2 can 
be kept at k.sub.1 N.sub.1 /2 within a wide range of N.sub.2 in case of 
large power requirement. Of course, an increase in the tranferrable power 
also brings about a further increase of the torque M.sub.2 at low speeds. 
In the simplest case, k.sub.2 =U.sub.2 /N.sub.2 can be changed by a gearing 
installed between motor and driven side. This combination is frequently 
found in hydrodynamic converter gear shifts. In addition to this, there 
are further very simple possibilities of changing k.sub.2 in the case of 
the electrical converter. Since the countervoltage U.sub.2 =k.sub.2 
N.sub.2 of a dc motor is proportional to the speed N.sub.2, the induction 
B.sub.2 and the active conductor length, k.sub.2 itself must be 
proportional to B.sub.2 and to the active conductor length. The 
possibility is thus provided of so adjusting k.sub.2, by changing the 
active conductor length in the motor or by changing the induction B.sub.2, 
that the necessary power is always available. 
The change in the field will have little effect in practice since the field 
of the motor M of the invention is advantageously produced by permanent 
magnets. On the other hand, two simple possibilities, based on the type of 
construction, offer themselves for controlling k.sub.2 via the change in 
the active conductor length. Since the dc motor M is preferably so 
constructed that a stationary winding W.sub.2 lying on a cylinder wall 
dips into the air gap of a pole wheel P.sub.2 (FIG. 4), the depth of 
immersion can be continuously varies by means of the carriage S. In this 
way, however, the active conductor length l.sub.2 and k.sub.2 are also 
changed, so that this arrangement has the function of an infinitely 
variable transmission. 
For practical use, however, even a step-wise change of K.sub.2 is 
sufficient, which can be effected in simple fashion by section-wise 
connection or disconnection of conductor lengths l.sub.2. Thus, for 
instance, the total conductor length l.sub.2 can be divided into 16 pieces 
.DELTA.l.sub.2 =l.sub.2 /16 and the motor M operated with an effective 
conductor length of j.multidot..DELTA.l.sub.2 /16. FIG. 5 shows that with 
large k.sub.2 (i.e. j=16) a very large torque is obtained with N.sub.2 =o 
and that between a lower speed N.sub.2(u) and an upper speed N.sub.2(o) 
there is present a wide range of practically optimum power matching. The 
constant steps .DELTA.1.sub.2 of the conductor length have the result that 
with low speeds with narrow power maximums, a narrow stepping takes place 
and at high speed with widened power maximums, the steps become more and 
more coarse so that the mismatch of the power remains limited to about 1% 
within a very wide range of speeds. 
The matching of K.sub.2 to the operating condition by the use of one of the 
above-indicated methods, therefore, results in a broadening, pursuant to 
the invention of the region of maximum power transmission. 
For the function in accordance with the invention of the electric torque 
converter, it is immaterial how the generator G produces a triangular 
voltage characterized by Eq. 1. Nevertheless, one particularly simple 
construction of such a generator G will be proposed. 
The pole wheel P.sub.1 of the generator G (FIGS. 6 and 9) consists of an 
inner ring and an outer ring, each having 2n permanent magnets PM, the 
poles of which are opposite each other in such a manner as to alternately 
produce zones with a radially inward (x's in FIG. 6) and a radially 
outward (dots in FIG. 6) extending magnetic field. The magnetic field is 
closed by inner and outer magnetically conductive PG,13 rings R. The 
cylindrically arranged winding W.sub.1 dips into th air gap, and the 
components of the conductor lengths which extend parallel to the axis of 
rotation of the pole wheel P.sub.1 are perpendicular to the relative speed 
.nu. and to the magnetic field. 
In FIG. 7a, the winding W.sub.1 is shown in such a manner that the plane of 
the air gap lies in the plane of the paper. The time t=0 is so selected 
that entrance 1, reversal point 3 and exit 5 of the V-shaped conductor 
loop W.sub.1 coincide with the magnetization limits of the pole wheel. The 
path s is then also zero at t=0 and increases with s=v.multidot.t. The 
active conductor length which lies in the direction of the axis of 
rotation, i.e. the length lying in FIG. 7 in the direction of the 
magnetization limits, can now be easily indicated as a function of s. The 
contributions of the individual conductor lengths to the voltage u.sub.1 
are to be counted positively or negatively depending on the direction of 
travel of the conductor and the direction of the magnetic field, namely: 
EQU u.sub.1 
.about.(+l.sub.12).multidot.(-B)+(+l.sub.23).multidot.(+B)+(-l.sub.34).mul 
tidot.(+B)+(-l.sub.45).multidot.(-B) (Eq. 14a) 
and 
EQU u.sub.1 
=v.multidot.B.multidot.[-a+(1-a)-a+(1-a)]=v.multidot.B.multidot.(21-4a) 
(Eq. 14b) 
respectively. 
From FIG. 7, it can be noted that a/s=1/(U/2n) or a=1.multidot.s/(U/2n). 
Since the paths s and the magnetization width (U/2n) behave like the times 
t and .DELTA.T/2, Eq. 14b becomes: 
EQU u.sub.1 
(t)=v.multidot.B.multidot.(21-81.multidot.t/.DELTA.T)=2v.multidot.B.multid 
ot.1.multidot.(1-4t/.DELTA.T) (Eq. 14c) 
At t=.DELTA.T/2, entrance 1, reversal point 3 and exit 5 of the conductor 
loop again coincide with magnetization limits and the process commences 
with reverse direction of field and voltage, i.e.: 
EQU U.sub.1 (t)=-2v.multidot.B.multidot.1.multidot.(1-4t/.DELTA.T) (Eq. 14d) 
Finally, n conductor loops can be arranged on the periphery U of the 
cylindrical winding W.sub.1 which loops then all have the same relative 
rotary position s with respect to the magnetization limits (FIG. 7b). They 
can, therefore, be connected in series and increase u.sub.1 (t) by the 
factor n. If one finally writes 2n.multidot.v.multidot.B=U.sub.1, then 
Eqs. 14c and 14d pass into Eqs. 1a and 1b. 
As shown in FIG. 7c, further conductors extending in a triangular pattern, 
for instance 2, 3 . . . 8, 1', 2', . . . 8' can be internested with 
conductor 1. With, in general, i=1 . . . I, i'=1 . . . I windings which 
are internested in each other, however, only pairs i and i' supply 
opposite in-phase voltages u.sub.1i (t)=-u.sub.1i, (t). 
One advantage of the invention resides now specifically therein that for 
all 2.multidot.I strands, the circuit shown in FIG. 1 can be developed 
separately and in this way, the power to be transmitted by the capacitors 
C.sub.i and the diodes D.sub.i.sup.+ and D.sub.i.sup.- is so limited that 
even with a large total power P, traditional components can be used. The 
impressed currents of the individual strands can then be summated on a 
pair of windings W.sub.2.sup.+, W.sub.2.sup.- or on several groups of 
pairs of windings. 
The division of the motor winding W.sub.2.sup.+, W.sub.2.sup.- into several 
groups also affords advantages in accordance with the invention since in 
this way, the power to be transmitted by the commutating means can be so 
limited that, for instance, with a collector-less embodiment, traditional 
power semiconductors can be used. This division is also possible when 
manufacturing tolerances and material dispersion lead to small voltage 
differences between the winding strands W.sub.2i .+-. since all are 
supplied by different winding strands of the generator G, i.e. from in 
each case their own current source. 
In FIG. 8a, such a division into groups of strands is shown by way of 
example. First of all, the four strands 1, 5, 1' and 5' of FIG. 7c are so 
combined that their positive currents i.sub.1, i.sub.5, i.sub.1 ' and 
i.sub.5 ' behind the diodes D.sup.+ are summated at U.sub.2.sup.+ while 
the corresponding negative currents -i.sub.1, -i.sub.5, -i.sub.1 ' and 
-i.sub.5 ' are summated at -U.sub.2. The manner of operation of an 
individual strand is not affected by the fact that further strands are 
connected to the common voltage +U.sub.2 or -U.sub.2. The strands are so 
selected in accordance with the invention that with power matching the 
current pulses are superimposed, as shown in the Table of FIG. 8b, to form 
a continuous direct current. The remaining strands (FIG. 7c) are also 
combined into groups (2, 6, 2',6'), (3, 7, 3' , 7'), (4, 8, 4',8') (FIG. 
10). 
The windings of the motor M are so located that the conductors extend in 
meander shape within the air gap of a pole wheel P.sub.2 of the motor M 
which is of a construction similar to the pole wheel P.sub.1 of the 
generator G (FIG. 6). In the ideal case, each conductor would then develop 
an alternately positive and negative square voltage as countervoltage. 
Since, however, a square course of the field in the pole wheel P.sub.1 can 
be obtained only with difficulty, an approximately trapezoidal course 
(FIG. 8c) is obtained for the voltage u.sub.2 (t) of a strand. If, for 
example, of the 12 strands of the motor M, the strands 1, 5 and 9 are 
selected, then at any moment at least one of the strands has the voltage 
+U.sub.2 and another the voltage -U.sub.2, i.e., for instance, at time 
t.sub.o (FIG. 8c), the strands 5 and 1. If now, in each case at the 
correct moment, the correct switch S.sub.i .+-. in FIG. 8a is actuated and 
if, therefore, for instance, at the time t.sub.o the switches 
S.sub.1.sup.- and S.sub.5.sup.+ are closed, the positive and negative 
generator currents can flow in each case through the corresponding winding 
strands of the motor M. The remaining strands of the motor are, of course, 
also combined into groups (FIG. 10). 
The switches S.sub.i .+-. can be either power semiconductors or 
mechanically acting commutators. However, since the winding cylinders 
W.sub.1 and W.sub.2 are advantageously arranged fixed in position and the 
pole wheels P.sub.1 and P.sub.2 can turn with respect to them at different 
speeds N.sub.1 and N.sub.2, electronic commutating without mechanically 
moved parts is certainly advantageous. An interchanging of the switch 
sequence of S.sub.i .+-. permits a reversal in direction of rotation in 
simple manner. 
Although the function in accordance with the invention of the electric 
torque converter is not dependent on the construction which has been shown 
by way of example, the construction shown in FIG. 9 results in case of 
realization of the functions in accordance with the invention. 
A support structure Tr of rotational symmetry can be fastened by a flange 
F1 to the machine (not shown) which produces the input torque M.sub.1. Tr 
furthermore contains the mounting La and La2 for the drive shaft We1 and 
the driven shaft We2. Finally, Tr bears the cylindrical winding W.sub.1 of 
the generator part G and the winding W.sub.2 of the motor part M. 
The pole wheels P.sub.1 and P.sub.2 which bear the permanent magnets PM 
(FIG. 6) are fastened on the shafts We1 and We2. It is advantageous to 
arrange the larger magnetic surface of the pole wheel P.sub.2, resulting 
from a higher driven mount M.sub.2 in two concentric systems, in which 
case then, as a whole, less material is necessary for magnets and returns. 
Of course, in such case, the motor winding W.sub.2 must also be arranged 
in two concentric cylinders. The capacitors c.sub.i, the diodes 
D.sub.i.sup.+ and diodes D.sub.i.sup.- as well as the commutating means 
(FIG. 8a) can be fastened in a readily accessible manner alongside the 
flange F1 to the support structure Tr. 
The present invention can be embodied in other specific forms without 
departing from the spirit or essential attributes thereof and, 
accordingly, reference should be made to the appended claims, rather than 
to the foregoing specification as indicating the scope of the invention.