FR2488753A1 - ELECTRIC MOTOR CONTROL WITH ALTERNATING CURRENT - Google Patents

Abstract

THE INVENTION CONCERNS CONTROLS OF ALTERNATIVE CURRENT ELECTRIC MOTORS. IT RELATES TO A COMMAND IN WHICH A DELAY CIRCUIT 16 CONTROLS A SWITCHING CIRCUIT 18 HAVING SWITCHES 24A AND 24B. ACCORDING TO THE INVENTION, AFTER THE CLOSING OF THE SWITCH 14, THE DELAY CIRCUIT 16 CONTROLS THE TRANSMISSION OF AN INCREASED AVERAGE VOLTAGE TO THE MOTOR 12 AND, AFTER THE EXPECTED DELAY, OPENS THE SWITCH 24A AND CLOSES THE SWITCH 24B IF ALTHOUGH MOTOR 12 RECEIVES LOWER AVERAGE VOLTAGE. APPLICATION TO THE REDUCTION OF ENERGY CONSUMED BY ALTERNATIVE CURRENT ELECTRIC MOTORS.

Description

The present invention relates to the commands of

  AC electric motors and more precisely-

  Such a control ensures the transmission of a high average voltage to the motor during start-up and, in order to save energy, reduces the average value of the voltage transmitted to the motor after the start-up.

  and during the normal operation phase of the engine.

  The control according to the invention is suitable for various

  types of AC electric motors but

  comes particularly well to induction motors. In

  the latter, the maximum power is usually

  summed during the start-up and they are obviously made so that they give the necessary torque ensuring start-up although the number of turns of the windings

  and other parameters needed to get started

  are not absolutely necessary for normal operation. As a result, much too high currents flow through the windings during normal operation and give off Joule heat, representing not only a loss of energy but also a risk of thermal deterioration of the motor and motors.

organs placed around.

  U.S. Patent No. 4,052,648 discloses an engine control in which the average voltage transmitted to the motor during the start-up period is greater than that of the next normal operating phase. In the control described in this patent, however, the power factor of the transmitted energy

  motor is determined by a relatively complicated circuit.

  the voltage transmitted to the motor is adjusted

  This detected power factor keeps a controlled value. The present invention is intended to enable

  the energy savings indicated for this order de-

  written in the aforementioned patent, with however a command much less complicated and expensive and yet more reliable,

  more flexible and easier installation.

  More specifically, the invention relates to a

  AC electric motor, connected to

  an alternative source of energy by means of a

  mutation. The control depends on the switching device

  after "closing" it first transmits a high average voltage to the motor and then, after the lapse of a given period of start-up, it automatically transmits a lower average voltage

  to the motor, this subsequent voltage being substantially fixed.

  In a particular variant, the invention

  surrounds a command of the voltage transmitted to an engine that

  can be switched between two different states in the-

  which it transmits different average voltages to the motor, and comprising a circuit associated with controlled delay following the "closing" of the switching device and intended to maintain the control in a first state after this closure and then to switch the control to its other

  state at the end of the delay period.

  In another variant, the power supply of the motor is controlled by a bidirectional controlled switch or a similar bidirectional switching device connected in series with the motor, by determining the voltage

  transmitted to the engine during normal operation by a cir-

  firing of the two-way switching device

  recurrent at a practically fixed moment in each half

  current cycle of the alternative source; a start-up trip circuit includes a delay circuit

  and, during the course of this delay, transmit to the

  bidirectional trigger signals which, at each half-cycle of the AC power supply, appear rather than normal operation trigger signals.

  Other features and advantages of the

  will become apparent from the following description,

  with reference to the accompanying drawings in which: - Figure 1 isa schematic partly in block diagram of an engine control according to the invention; FIGS. 2 to 6 are diagrams partially in synoptic form of commands according to other embodiments of the invention; FIG. 7 is a partial diagram of an order

  similar to that of Figure 6 but including a

  Bidirectional transmitter different from that of Figure 6; and FIGS. 8 to 12 are diagrams partly in synoptic form of commands according to other modes of

embodiment of the invention.

  In the drawings, FIG. 1 represents a single-phase motor 12, for example an induction motor, connected to a

  AC power supply by means of a communication device

  mutation in the form of a main switch 14 and associated

  assigned to a command according to the invention. This command includes

  a delay circuit 16 controlled by the closing of the switching

  14, and a voltage adjusting circuit 18 associated with the

  delay circuit. The latter sets a delay after the

  switch setting. It can be mechanically connected to the switch 14 so that it is triggered mechanically

  by closing the switch, or it can be electrically connected

  to the motor 12 in order to be electrically tripped

after closing the switch.

  The combination of the delay circuit 16 and the circuit

  The voltage control furnace 18 has two different states, one of which transmits a high average value voltage to the motor 12 and the other transmits a lower average value voltage which is substantially fixed to the motor. The delay circuit 16 adjusts the state of the

  combination and causes the transmission of a moderate voltage

  yenne high just after closing switch 14 and a lower fixed average voltage after the end of the

delay period.

  In an exemplary embodiment of the voltage regulation circuit 18 of FIG. 1 and as represented in FIG.

  lines interrupted in this figure, the circuit may

  take a transformer having a secondary 20 comprising a fixed number of turns connected to the motor, and a primary 22 connected to an AC power supply by a variable number of turns, controlled by a switch 24a, 24b. During the start-up period, the delay circuit 16 opens the switch 24b and closes the switch 24a so that it turns on a small number of turns of the primary, so that a high average value voltage

  This is transmitted to the engine 12. After the

  delay period, circuit 16 closes the

  24b and opens the switch 24a so that the number of turns of the primary is reduced and the voltage

  corresponding lower average is transmitted to the engine 12.

  FIG. 2 represents a circuit according to the invention

  in which the voltage regulator circuit 18 of the

  FIG. 1 comprises a bidirectional controlled switch, as indicated by the reference Q, having its terminals

  main series of series with the motor 12 and a cir-

  cooked associated boot angle adjustment partner 26 which, in

  cooperation with the delay circuit 16, is intended to trans-

  set trigger signals to terminal 28 of

  switching off; during the start-up period,

  the switch is controlled at each half cycle of the

  relatively early, while during the normal period of normal operation priming is

  at a fixed time posteriorly. As a result,

  During the start-up period, the motor 12 is powered

  for a longer time at each half cycle and therefore receives a higher average voltage while, after the start-up period, it is powered for a period of time.

  shorter at each half-cycle, so that the

Yenne has a lower value.

  In the circuit of Figure 2 and in the cir-

  In the following figures, an RC circuit comprising a resistor R3 and a capacitor C4 connected in series is connected to the main terminals of the bidirectional switch.

  Q. This RC circuit limits the growth of the voltage

  dV / dt switching voltage produced by the inductive load

  the engine and thus prevents a faulty ignition of the com-

  bidirectional mutator due to the dV / dt constraint of

  tation. This RC circuit is not always necessary and can sometimes be removed, for example when the inductor

engine is relatively small.

  In the circuit of FIG. 2, the delay circuit 16 and the ignition angle adjusting circuit 26 are both connected in parallel with each other at the same time.

  terminals of the series circuit comprising the motor 12 and the

  However, this is not the only possible arrangement. In fact, the bidirectional switch Q may be mounted on either side of the motor and the boot angle adjusting circuit 26 and / or the delay circuit 16 may each be mounted across the switch. bidirectional Q in such a way

  that the motor 12 is included or excluded.

  For example, FIG. 3 represents a control according to the invention in which the delay circuit 16 is connected to the terminals of the bidirectional controlled switch Q

  but with exclusion of the motor 12, and the circuit 26 of

  boot angle is connected to the terminals of the

  bidirectional switch so that it includes the motor 12.

  In the circuit of FIG. 4, the delay circuit 16 and the control circuit 26 are both mounted

  directly to the terminals of the bidirectional com-

  Q and exclude the motor 12. This arrangement pre-

  has the advantage of allowing the arrangement of the entire control as a single element 30 to be serially connected with the motor 12 (i.e. its inductor coil) and the switch 14 so that that the

  packaging and installation are simplified.

  FIG. 5 represents a circuit comprising a control according to the invention in which the delay circuit 16 is mounted at the terminals of the series combination of the motor

  12 and the bidirectional controlled switch Q, and the cir-

  cook 26 of setting the starter angle is directly con-

  connected to the terminals of bidirectional switch Q, with ex-

  clusion of the engine. In addition, this figure shows a particular construction of the boot angle adjusting circuit 26. This illustrated circuit comprises a trip circuit for normal operation comprising a resistor and a capacitor 32 connected in series with each other

  connected to the main terminals of the two-way

  rection Q and a circuit 34 with threshold voltage, by

  example a controlled unidirectional switch or an

  neon hen connected to the connection of the resistor 30 and the capacitor 32 and to the trigger terminal 28 of the

  bidirectional controlled switch Q. This circuit of de-

  Normal latching is open-loop and, for a given voltage and frequency of the AC source, it transmits trigger signals to the bidirectional switch Q at a time substantially fixed to each half-cycle of the power supply. Thus, in the initial part of each half-cycle, the capacitor 32 charges through the resistor 30 to the breakdown voltage of the threshold circuit 34 and, at the latter moment, a

  current flows in the trigger 28 and triggers the

bidirectional controller.

  A start trip circuit is also connected to the trigger 28 and includes a resistor 36.

  current limitation and a set of contacts 38. These

  are delayed by circuit 16 so that they close during the start-up period or during the delay and they open and remain open after the end

  delay or start-up period. Thus, this cir-

  cooked 16 delay works under the control of the switch

  14 and immediately close the contacts 38 when closing

  switch 14 then opens them at a predetermined time.

  subsequent period, so that it establishes the

  on the way. During this, at each half cycle of the food

  the current flows through the closed contactors

  38 and the resistor 36 and will cause conduction of the commuta-

  bidirectional controller Q earlier in each half-cycle.

  This triggering of this bidirectional switch during

  the start-up period is earlier than the start-up

  caused in the normal operating phase so that the average voltage transmitted to the motor is higher

  during start-up only during normal walking.

  As shown in FIG. 5, the trigger circuit

  The start-up device is directly connected to the trigger 28 of the bidirectional switch but, if necessary, it can also be connected to the trigger via the voltage threshold circuit 34, for example by connecting the end of the switch. lower represented resistance 36 at

  left and right side of circuit 34.

  In the control of FIG. 5, the delay setting function which determines the start-up period is fulfilled by the delay circuit 16 which is substantially separate from the start-up trip circuit and which can be constituted by any of many known delay circuits. On the other hand, Figure 6 shows a circuit in which the motor control also includes a bidirectional controlled switch Q,

  a normal walk release circuit and a cir-

  cooked start trigger but in which the

  function of delay is ensured by the trigger circuit-

  start-up. As shown in FIG. 6, the normal trip trip circuit further comprises a resistor in the form of a potentiometer P2, connected in series with a capacitor C3, to the main terminals of the bidirectional controlled switch Q and to the trigger 28

  via a voltage threshold circuit 34.

  The start-up trip circuit of Figure 6 includes a timing RC series circuit which

  has a potentiometer P1 and a capacitor C2. This cir-

  cooked RC is mounted between the trigger 28 and the main terminal

  upper blade of bidirectional switch Q through

  diode bridge D1, D2, D3 and D4 which imposes

  Circulation of the RC circuit current in one direction.

  The operation of the tripping circuit

  starting of Figure 6 is as follows. After the

  switching of the switch 14, the capacitor C2 is discharged

  normally. Then, during each half-cycle of the

  positive voltage, a current flows in the motor 12, the diode D1, the potentiometer P1 and the capacitor C2, and

  the diode D4 towards the trigger 28 so that the switching

  Bidirectional transmitter Q is turned on during this half-cycle. At each negative half-cycle of the AC power supply, the current flows through trigger 28 and

  circulates in the diode D2, the potentiometer P1 and the con-

  capacitor C2 and the diode D3 to the motor 12, and the

  rant flowing through the trigger 28 causes the bi-directional bidirectional switch to be turned on

Q during this half cycle.

  Thus, during the start-up period, the

  bidirectional controlled switch Q is set to the con-

  earlier in each half cycle of the diet. from

  that the bidirectional switch is set to the conductive state

  the charge of the capacitor C2 stops for this half-cycle, but a small additional charge is added

  in the capacitor at each half cycle so that, when

  that the timing period is progressing, a current of de-

  triggering is flowing in the trigger 28 more and more

  later in successive half-cycles until final

  the trigger signal transmitted by the start-up tripping circuit coincides with the tripping signal transmitted by the tripping circuit.

normal procedure.

  The time required for capacitor C2

  gradually reach the necessary

  the duration of the start-up period and, secondly, the timing of the initiation of the bidirectional controlled switch Q is

  fixed by the trigger signals of the circuit de-

normal walking clutch.

  The circuit of FIG. 6 also includes a circuit

  fired discharge capacitor C2 timing after the-

  switch 14. This discharge circuit may simply

  a high-value resistor, connected in parallel with potentiometer P1 and capacitor C2,

  but it is preferably represented as two resistances

  R1 and R2 mounted between the connections 40 and 42 of the

  diode bridge and the lower main terminal of the

  bidirectional transmitter Q, with a capacitor C1 connected in parallel with the resistor R1. The values of the resistors R1 and R2 and of the capacitor C1 are chosen so that the capacitor C2 discharges rapidly when the voltage transmitted to the motor decreases, for example not only following the opening of the switch 14 but also following the temporary disappearance of the current of the source or the temporary opening of thermal overload switches incorporated in the motor 12. During the normal implementation of the start-up period, the

  capacitor C1 maintains the charge of capacitor C2 during

  at times when the bidirectional controlled switch Q leads. However, when the motor no longer receives energy, the capacitor C1 quickly discharges through the resistor R1 and thus allows the discharge of the

  capacitor C2, the entire discharge process

  a short time. Consequently, when the energy transmitted to the motor is interrupted for more than a short time, when the energy is restored, it is transmitted

  the motor at the high average value controlled by the cir-

  turn off on the way. In the circuit of FIG. 6, the potentiometer P1 can be adjusted so that it varies

  the duration of the start-up period and the potential

  meter P2 can be set to vary the

  their average voltage transmitted to the motor during the

  normal walking phase. These potentiometers can of course

  replaced by fixed resistors when these

  settings are not necessary or desirable.

  As mentioned above, it is possible to use

  different types of bidirectional switches

  the adjustment of the current flowing in the motor 12. For example,

  when the energy consumed by the engine 12 is

  However, the bidirectional controlled switch Q of FIGS. 2 to 6 can be replaced by a

2488753 -

  bidirectional switching as indicated by reference numeral 44 in FIG. 7. This switching device comprises a controlled bidirectional switch Q, two triode inverse blocking thyristors SCR1 and SCR2 and associated resistors and diodes as indicated in the figure. In this circuit, the bidirectional controlled switch does not regulate

  directly feeding the engine but

  milk the triode thyristors. Resistors R4 and R6 constitute conventional cathode resistors associated

  thyristors, but they may not always be

  and sometimes they can be deleted.

  During the operation of the circuit of FIG.

  during a half cycle of the positive voltage, the switching

  controlled bidirectional transmitter Q is turned on by a trip signal. The current then flows from the motor in the diode D5, the resistor R5, the bidirectional switch controlled Q then the trigger at

  the cathode of the SCR1 thyristor which is thus put into the state con-

  ducer. The voltage drop in this thyristor thus decreases to a low value and causes the conduction of the control circuit to be stopped, all the voltage of the source being

  transmitted to the engine during the remainder of this half-cycle.

  During a negative half cycle, the bi-directional switch

  directional Q is put in the conductive state by a signal of

  trigger and the current then flows from the li-

  lower power supply in diode D6, the switching

  bidirectional transmitter Q, the resistor R5 and between the gate and the cathode of the SCR2 thyristor which is thus put in the conductive state. When this phenomenon occurs, the voltage across this thyristor falls to a low value and causes the conduction to stop in the rest of the control circuit,

  the entire voltage of the source being applied to the motor

the remainder of the half-cycle.

  Sometimes, for example in the case of

  flow of bilge pumps or freezers, it may be desirable for the control to include a secondary or redundant control circuit ensuring the maintenance of the

-2488753

  engine operation in the event of a circuit failure

  main order. Figure 8 shows such an arrangement

  in which the main control circuit is similar to that of FIG. 4 and comprises a controlled bidirectional switch Q1 associated with a delay circuit 16 and an ignition angle setting circuit 26 comprising a resistor 46, a capacitor 48 and a voltage threshold circuit 50. The secondary control circuit comprises a controlled bidirectional switch Q2, an associated delay circuit 52 and an ignition angle setting circuit 54, the latter comprising a resistor 56, a capacitor 58

  and a voltage threshold circuit 60. An indicative device

  62, for example a light emitting diode, is connected to the trigger of the bidirectional controlled switch Q2 so that it gives an indication of when the current flows in this terminal. The delay circuits 16 and 52 may be similar to each other generally and to the delay circuit of FIG. 6, but the circuit components 52

  should be chosen so that they set a slight delay

  higher than the one fixed by circuit 16 to

  later. In addition, the components of the firing angle adjusting circuit 26 are selected to control trigger signals appearing slightly before the firing signals controlled by the components of the fader angle secondary circuit 54. boot. In

  consequence, during the normal operation of all the cir-

  cooked, the triggering signals for

  put by the delay circuit 16 control the getting started

  of the motor 12 via the bidirectional switch

  Q1 and the triggering signals

  normal channel transmitted by the circuit 26 control the function

  subsequent normal operation of the engine 12, via

  of the bidirectional controlled switch Q1. However, if the circuit-16 breaks down, the startup of the motor is ensured by the circuit 52 which operates in cooperation

  with the bidirectional controlled switch Q2; if the

  cooked 26 breaks down, the normal operation of the engine

  12 is provided by the circuit 54 in cooperation with the

  bidirectional controlled mutator Q2. If the bidirectional controlled switch Q1 fails and remains open

  or transmits too low a voltage to the motor, the switching

  controlled bidirectional transmitter Q2 and the associated circuits 52 and 54 provide both the start-up command

  and normal engine running. Whenever the community

  controlled bidirectional transmitter Q2 provides a part or

  motor control, indicator 62 lights up

  me and indicates the presence of any failure in the circuit. The circuit of FIG. 8 also comprises a manual switch 62 which can be closed so that the motor constantly receives all the voltage of the source,

* the motor control is then shunted.

  The control according to the invention is suitable not only

  not only to single-phase motors but also to polyphase motors.

  For example, Figures 9 and 10 show the control according to the invention applied to three-phase motors. In FIG. 9, the control of the three-phase motor 64 shown is ensured by three identical control assemblies 66 each connected to one of the three power supply lines 68.

  the engine, in series with the main switch 70.

  any of the sets 66 is analogous or may be analogous to

  any of the circuits described with reference to the

  1 to 8. The controls in Figures 4 and 6 are

  particularly advantageous when the engine 64 has a

  thermal overload protection device or other device causes the circuit to open between the

control and the engine.

  When the engine has no pro-

  thermal protection or when it does not include other

  devices allowing the opening of the circuit between the

  the motor, you can use a simple command

  as shown in Figure 10. In this case, each

  that line 68 of the engine contains a bidirectional switch

  commanded 70 or another bi-directional switching device

  directional control (or a transformer or other

  positive voltage regulator), a start trip circuit comprising a resistor 72 and a set of contacts 74, and a boot angle adjustment circuit 76

  transmitting control signals to the trigger of the com

  associated bidirectional controller 70 (or transformer or other voltage adjuster) at a time set at each half of the power supply. A delay circuit 78 is mounted between two of the lines 68 of the

  motor and, via a switch 80,

  Means a relay coil R-1 for contact control 74. When main switch 70 is closed, delay circuit 78 closes switch 80 and

  feeds the R-1 winding so that it simultaneously closes

  the contacts 74, thereby causing the

  the three three-way switches controlled 70 on each half cycle. At the end of the period of delay

  by the circuit 78, the switch 80 is open and no longer supplies the relay R-1 and the contacts 74 open if

  although the control of the bidirectional switches

  70 passes to the amperage angle adjustment circuits 76.

  which triggers the bidirectional switches later at each half cycle so that the motor 64 receives lower average voltages. The contacts 74 and the associated resistors 72 may also be placed in the ignition angle setting circuits 76 (upstream of the voltage threshold circuits) so that they provide

  early triggering of bidirectional switches

summoned 70.

  In the embodiments described above,

  the switching device which, during the transition from opening to closing (that is to say from the non-conductive state to the conducting state) starts the motor

  associated, is represented as a main switch

  pal mounted in series with the AC power source and the motor. The location of the switching device is

  however not the only one possible. Thus, the figure ilrepres-

  a control circuit similar to that of FIG. 4, comprising a controlled bidirectional switch Q connected in series with a motor 12, a delay circuit 16 and a boot angle adjusting circuit 26 being connected in parallel with the motor. one with the other and being connected to the terminals of the bidirectional controlled switch. However, in this case, no switch is connected in series with the motor 12 and the switching device comprises on the contrary a

  switch 82 placed in the control circuit. The cir-

  cooks 16 to delay and the circuit 26 to adjust the angle

  primers transmit, during operation,

  Trigger release valves 28 of the bidirectional controlled switch Q. When the switch 82 is open (i.e., it does not drive), it stops the operation of the delay circuit 16 and the circuit 26 thereof. setting the booting angle and thus prepares them not to

  transmit trigger signals to the bi-directional switch

  directional controlled Q so that the motor 12 is not powered. When the switch 82 is closed (or turned on), it supplies the delay circuit 16 and the boot angle adjusting circuit 26 and causes the triggering signals to transmit to the bidirectional switch. ordered Q, and the engine is

  therefore fed in the manner described above with reference

the circuit in Figure 4.

  In FIG. 11, the switch 82 is shown mounted in the line connecting the delay circuit 16 and the setting circuit 26 to the connection of the motor 12 and the controlled bidirectional switch Q, but this location of the switch 82 in the circuit of FIG. command is not the only possible, since it can occupy other locations such as for example in the line that transmits signals

  Trigger trigger 28.

  In the embodiments of the invention de-

  previously written for single-phase motors, with reference to FIGS. 1 to 8 and 11, it has been assumed that the motor 12 comprises either a single winding or two or more windings connected in parallel, the control being connected

  the engine so that it acts directly on all

  bearings. However, this characteristic is not

  and when the engine has at least two

  The control unit can be connected to the motor in such a way that direct voltage regulation is ensured for only one of the windings. FIG. 12 represents an example of such a control similar in general to that of FIG. 4, associated with a motor 84 which is a distributed permanent magnet and capacitor induction motor, having a normal winding 86 and, in parallel, an auxiliary winding or starting 87 connected in series with a capacitor 88.

  control circuit is mounted so that it acts di-

  right on the winding 86 of normal walking, this

  connection being ensured by mounting the two-way switch

  rectionnal controlled Q in series with the single winding 86.

  The delay circuit 16 and the control circuit 26 of the

  are both represented linked to the bor-

  Q is a non-essential feature and one or both of these circuits can be

  the serial combination of the bidirectional switch

  Q and winding 86 normal running.

  It is understood that the invention has not been

  It is written and represented only as a preferred example and any technical equivalence can be added to its constituent elements without departing from its scope.

Claims (38)

  An AC electric motor drive having at least one winding and associated with an alternating current source and a switching device which can be switched between closing and opening conditions, said control being characterized in that it comprises a control circuit (16, 18) controlled solely by switching the switching device from its open state to its closed state and intended to transmit first the energy of the source to the winding of the motor at a high average voltage during a period of start-up that has a certain duration, and then automatically transmit the energy of the source to the winding of the   motor at a lower average voltage, this dynamic voltage   lower yenne being practically fixed for a fixed frequency and voltage of the electric current of the source of alternating current.   2. Control according to claim 1, characterized in that it comprises an open loop circuit (22, 24a, 24b; 30, 32, 34; P2, C3, 34; 46, 48, 59) formed in the circuit of order and intended to establish the value of the lower average voltage.   3. Control according to claim 2, characterized in   what the open loop circuit intended to fix the va-   their lower average voltage includes an RC series circuit (30, 32, P2, C3; 46, 48) combined with a voltage threshold (34; 50).   -4. Control according to claim 2, characterized in   it includes a device (P1, C2) incorporated in the cir-   cooked order and intended to establish the duration of the period   start-up, this scheme establishing, for a period   quence and a given voltage of the current of the alternating   native, a start-up period of almost predetermined duration. 5. Control according to claim 4, characterized in   what the device intended to establish the duration of the   The start-up circuit comprises a timing circuit RC (P 1 C2) electrically connected to the other components of the control so that, just after switching of the switching device from its opening condition to its condition.   closing the capacitor charge (C2) increases   each half-cycle of the alternating current source, and a device (P2, C3, 34) controlled by the   charging the capacitor of the timing circuit RC when   it reaches a determined value and intended to interrupt the start-up period and then to transmit energy from the source to the motor winding at said lower average voltage.   6. Control according to claim 1, characterized in that the control circuit is entirely placed in a   assembly (30) connected in series with the winding of the motor.   7. Control according to claim 1, characterized in that the motor is a permanent magnet induction motor and distributed capacitance having a winding (86) of normal operation and an auxiliary winding (87) connected in parallel with L other, and the control is such that the control circuit is fully housed in a mounted assembly.   series with normal walking winding.   8. Control according to claim 1, associated with a polyphase motor connected to the AC power source.   by a corresponding number of supply lines, la-   said control being characterized in that the control circuit is fully housed in a corresponding number   identical sets (66) each connected to one of the   Power supply units in series with the motor.   9. Control according to claim 1, characterized   in that the control circuit comprises a transforma-   (20, 22) with variable ratio of the number of turns,   mounted between the AC power source and the winding   of the engine, the switching device being a   main switch (14) connected in series with the source of   alternating current and winding of the motor, and a cir-   cooked (16, 24a, 24b) controlled by the closure of the   main transformer to set the transformer to transmit power from the source to the motor winding at the high average voltage during the start-up period and then automatically adjust the transformer so that the transformer it transmits the energy of the source to the winding of the motor at the average voltage weaker.   10. Control according to claim 1, characterized in that the control circuit comprises a controlled bidirectional switching device (Q) connected in series with the winding of the motor, and a circuit (16, 26) controlled by the switching of the device. switching from its open state to its closed state and intended to trigger   the bidirectional switching device earlier at each   that cycle of the source so that the energy of the source   is transmitted to the winding of the motor at the rated voltage   high during the start-up and decommissioning   then automatically switch on the switching device   bi-directional later at each half cycle of the source so that the source energy is transmitted to   motor winding at the lower average voltage.   11. Control according to claim 10, characterized   in that the bidirectional switching device com-   mandé is a bidirectional controlled switch.   12. Control according to claim 10, characterized   in that the bidirectional switching device com-   mandé has two triode thyristors with reverse blocking   mounted in parallel and in opposite directions.   13. Control according to claim 10, characterized in that the control circuit comprises an RC series circuit (30, 32; P2, C3) in combination with a threshold circuit   voltage device (34) for triggering the   bidirectional mutation at a substantially fixed point of each half-cycle of the alternative source after the start-up period so that the average voltage lower at   which the energy of the source is transmitted to the winding the engine is established.   14. Control according to claim 13, characterized in that the bidirectional switching device. a gate to which the voltage threshold circuit is connected and to which this circuit transmits the trip signals, and a start circuit (36, 38; P1, C2) connected to the trigger in parallel with the circuit   voltage threshold so that it transmits to the trigger,   During the start-up period, triggering signals   start-up that appear at each half-cycle   alternating current more; that the triggering signals   transmitted by the voltage threshold circuit.   15. Control according to claim 14, characterized in that the start-up circuit comprises a circuit (P1, C2) transmitting trigger initiation signals to the trigger during the start-up period, these triggering signals. getting started   earlier every half cycle of the alternating current and progresses   more and more later in each half-cycle until   what they appear simultaneously with the signals of de-   tripping transmitted by the voltage threshold circuit.   16. Control according to claim 1, characterized in that the control circuit comprises a controlled bidirectional switching device (Q) connected in series with the winding of the motor, and a circuit (P1, C2) controlled by the switching of the device. switching from its open state to its closed state and intended to initially trigger the bidirectional switching device   earlier at each half cycle of the alternating current source   tif, to trigger later the communication device   bidirectionally at later and later times in each half-cycle until a specific moment in each   half-cycle, and then trigger the communication device   bi-directional tilt at this particular moment of each half   as long as the switching device remains in the state closure.   17. Control according to claim 10, characterized in that the switching device is a main switch (14) connected in series with the power source   alternating and motor winding.   18. Control according to claim 1, characterized in that the control circuit comprises a controlled bidirectional switching device (Q) having two main terminals and a trigger, and the bidirectional switching device is electrically connected in series with the winding the motor by its two main terminals, a start-up trip circuit (36, 38; P1, C2)   being connected to the main terminals of the switching device   bidirectional signal and being adapted to transmit trigger signals to the trigger during the start-up period, these signals appearing early at each half-cycle of the AC current of the source, and a normal gating trip circuit (30, 32 , 34, P2, C3, 34) connected to the two main terminals and intended to transmit to the trigger trigger signals which appear at a later time substantially fixed to   each half-cycle of the current of the alternative source.   19. Control according to claim 18, characterized in that the normal gating trip circuit comprises a resistor (30, P2) and a capacitor (32; C3) connected in series and connected to the two main terminals,   and a voltage threshold circuit (34) mounted between the   the resistor and the capacitor and the trigger.   20. Control according to one of claims 18 and 19,   characterized in that the start-up trip circuit comprises a timing circuit RC (P1, C2), and a diode circuit (D1, D2, D3, D4) connecting the timing circuit between one of the two main terminals and the trigger so that the current flowing between this main terminal and the trigger and in the timing circuit can only flow in one direction in the timing circuit, and a discharge circuit (C1, R1, R2) connected to the circuit of   timing and intended to discharge this circuit after switching   switching of the switching device from its closed state to its open state so that when the switching device is switched from its open state to its closed state, the capacity of the timing circuit is progressively charged during the following half-cycles of the AC current of the source, the charging current flowing in   the trigger and triggering the two-way switching device.   recalibrated earlier at each half cycle until the   load capacity reaches a value such that the   The trip signal generated by the start trip circuit is displayed simultaneously with the trip signal produced by the trip circuit of the trip unit. normal operation.   21. Control according to claim 20, characterized in that the diode device comprises a diode bridge having a connection connected to said main terminal and an opposite connection connected to the trigger, and the RC timing circuit comprises a resistor and a capacitor connected in series with each other between the other two   diode bridge connections, the discharge circuit com-   taking a resistive circuit mounted between the other two diode bridge connections.   22. Control according to claim 21, characterized in that the discharge circuit comprises two resistors   (R1, R2) each mounted between one of the other two con-   nexions of the diode bridge and the other of the two main   of the bidirectional switching device.   23. Control according to claim 22, characterized in that it comprises a capacitor (C1) mounted between one of the other connections of the diode bridge and the other   main terminals of the two-way switching device   -directional. 24. Control according to claim 18, characterized in that the starting trip circuit is further connected directly to the two main terminals of the bidirectional switching device so that this device is in parallel with the trip circuit.   starting up excluding the motor winding.   25. Control according to claim 18, characterized in that the normal operation trip circuit is   connected to the terminals of the bidirectional switching device   in that it comprises the motor winding and the bidirectional switching device in series with each other and in parallel with the normal trip trip circuit.   26. Control according to one of claims 24 and 25,   characterized in that the start-up trip circuit is directly connected to the two main terminals of the bidirectional switching device so that   it is connected in parallel with the trip circuit.   start-up, excluding the winding up of the tor.   27. Control according to one of claims 24 and 25,   characterized in that the start-up trip circuit is connected across the bidirectional switching device so that it includes the motor winding and the bidirectional switching device in series with each other and in parallel with the circuit of triggering of start-up.   28. Control according to claim 18, characterized   in that the start-up trip circuit com-   carries a resistor (36) and a set of contacts (38) connected in series between one of the main terminals of the   bidirectional switching and trigger, and a   to close the contacts during the start-up period and to open them at the end of this period of getting started.   29. Control according to claim 1, intended for a   polyphase motor with multiple power lines,   said control being characterized in that it comprises a voltage control circuit (66, 70, 72, 74, 76) in each of the supply lines, each of the voltage control devices having, in association with it,   a delay circuit causing the transmission by the disc   positive control of voltage of a high average voltage to the motor during a period of start-up having a certain duration and then causing transmission by the voltage control device of a mean voltage weaker to the engine.   30. Control according to claim 18, intended for   polyphase motor with multiple power lines,   said control being characterized in that it comprises a bidirectional switching device (70) mounted in each of the supply lines, each bidirectional switching device being associated with a normal gating trip circuit (76) mounted between its terminals   main purpose and intended to transmit to the trigger   normal operating tripping devices appearing at a substantially fixed moment at each half-cycle of the current   alternative source, and each of the   bidirectional mutation is associated with a circuit of   start-up latch (72, 74) mounted between its main terminals and for transmitting triggering triggering signals to the trigger during the   start-up period, these signals appearing at each   that half cycle of the AC current of the source, plus   early as the moment substantially fixed trigger signals normal operation.   31. Control according to claim 30, characterized   in that the triggering circuit of start-up asso-   each two-way switching device   takes a resistor (72) and a set of contacts (74) mounted in series between a first main terminal of the bidirectional switching device and its trigger, and a single   delay circuit (78) mounted between two of the supply lines   tion and control by switching the switching device from its open state to its closed state so that it simultaneously closes all the sets of contacts and then simultaneously opens all the sets of contacts   after the end of the start-up period.   32. Control according to claim 18, characterized   in that it comprises a second switching device   Directional (Q2) connected in series with the winding of   motor and in parallel with the first communication device   Bidirectional Tation (Q1), a tripping circuit   normal operation (52) for the second communication device   bidirectional circuit, the circuit triggering   of the second bidirectional switching device   which is intended to transmit trigger signals   the second bidirectional switching device with   half-cycle of the alternating current from the source to one   slightly later than the occurrence of the trigger signals transmitted by the normal gating trip circuit associated with the first bidirectional switching device. 33. Control according to claim 32, characterized in that it comprises an indicator device (62) connected   to the trigger of the second bidirectional switching device   tional and intended to indicate the flow of a current in the trigger of this device.   34. Control according to claim 18, characterized in that it comprises a series circuit RC (R3, C4) mounted across the bidirectional switching device and intended to limit the rate of rise of the voltage of the   switching at the terminals of the switching device   bidirectional response by the inductance of the motor winding. 35. Control according to claim 1, characterized in that the control circuit comprises a device   controlled (Q) - connected in series with the current source al-   and the motor and intended to control the circulation   source current in the motor, a trip device (26) for transmitting trip signals to the controlled device, and the   switching is a device (82) which, when closed,   ture, prepares the triggering device so that it   transmits trigger signals to the device   which, when in the open state, prepares the triggering device so that it does not transmit   no trigger signals to the controlled device.   36. Control according to claim 28, characterized in that the normal gating trip circuit comprises a resistor (30) and a capacitor (32) connected in series and connected to the two main terminals and   a voltage threshold circuit (34) mounted between the   the resistor and the capacitor and the trigger, and the start-up trip circuit is connected to the trigger via the voltage threshold circuit. 37. Control according to claim 1, characterized   in that the motor is a magnet induction motor   distributed-capacity winding having a normal winding (86) and an auxiliary winding (87) mounted in parallel with each other, and the control circuit (Q) is connected in series with the normal winding,   excluding the auxiliary winding.   38. Control according to claim 1, characterized in that it comprises a feed line intended for   connect the motor to the AC power source, the cir-   cooked control includes a voltage control circuit   (20, 22, Q) placed in the feed line, and the cir-   delayed cooking (16) causes transmission through the circuit   voltage control of a high average voltage at the   the motor during a start-up period of determined duration and then causes the transmission by the voltage control circuit of an average voltage   weaker at motor winding.