JPH0210255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The invention relates to a loom equipped with a main electric drive such that the starting energy is primarily provided by an electrically movable flywheel connectable to the loom. Regarding the starting method and its circuit.

[Conventional technology]

Generally, a loom is driven by an electric motor connected to an alternating current or three-phase current system. The frequency of the system determines the rotational speed of the main drive as a function of the type of motor, for example the number of poles. This main drive drives a flywheel which is connected to the main drive shaft of the loom via a transmission, for example a belt transmission. After switching on the main drive, the flywheel is first accelerated to a corresponding rotational speed by the motor. To start the loom,
The flywheel is connected to the main drive shaft of the loom through a clutch brake unit so that the flywheel can move the loom from a standstill. The characteristics of the clutch, the stiffness of the motor, the size and frictional resistance of the acting flywheel give a certain speed course for the start of the loom, in particular for the flywheel on the one hand and for the main shaft on the other hand. Give a predetermined speed course. In that case, the speed of the flywheel after engagement of the clutch drops considerably until it synchronizes with the speed of the main shaft of the loom when it rises from rest.

In practice, special conditions are imposed on starting devices for such looms, such as, for example, that the loom must be fully engaged up to the first reed impact. In this connection process in the loom,
The loom is fully connected until the first reed collision;
The instantaneous rotational speed during the first reed impact is too low, resulting in so-called run-off points, ie points where the introduced weft threads are not struck in the correct position, resulting in large weft thread spacings. The result of the impinged weft threads with poor density thus produced is visible as a striped defect if a certain limit value is exceeded. In order to reduce the above-mentioned effects caused by too low a rotational speed when starting a loom, conventionally the motor is adjusted so that it reduces the instantaneous rotational speed to the desired final rotational speed as soon as possible after as few reel collisions as possible, i.e. as soon as possible. Consideration was given to making it strong enough to have a strength of over 96%. Otherwise, the result of insufficiently impinged weft threads will result in the above-mentioned poor quality stripes in the fabric. In practice, for example, the value for the instantaneous speed that can be reached is approximately the rated speed during the first reel collision.
The instantaneous rotational speed is more than 80%, and after the third reed collision, it is more than 96%. To achieve this value, attempts have always been made to employ large and durable motors and to obtain a light and durable structure for the reed drive. However, this approach is severely limited by the increased flywheel mass for the motor, clutch and loom, and also by the economical design of lightweight construction.

A similar problem arises in the case of weft looms with weft thread passing mechanisms, such as shuttles, which fly freely through openings between the warp threads. The firing speed of the shuttle must then be such that it reliably passes through the opening between the warp threads and exits it within short time limits. Here too, when starting the loom, the operating speed must be achieved very early, preferably before the first firing of the shuttle. A starting device for a loom for this purpose is known from German Patent No. 1535525.
In this starting device, in order to start the loom,
Before the clutch is engaged, the flywheel to be connected is driven to rotate at a higher speed than is normal during the weaving process. In order to drive the flywheel at a higher rotational speed than the operating speed before starting the loom, a constant speed drive motor is provided which drives the flywheel at a high rotational speed via a planetary gear system.

However, this known device requires an additional high outlay due to the planetary gear system. Furthermore, since the switching or starting process of the loom is dependent on the position of the clutch, the flywheel must be driven at a high rotational speed during the entire time the clutch is disengaged. This means that the loom is automatically stopped in the event of a defect, so that the clutch is disengaged and drives the planetary gear at a high rotational speed for the entire time during which the defect is eliminated.

The above-mentioned publication also describes another method, namely the use of a two-speed electric motor which is rotated at a high rotational speed when the clutch is disengaged. This saves on the cost of planetary gearing, and instead provides the necessary flywheel for the motor-driven gears. This device also has the disadvantage of being driven at a high rotational speed for a long period of time. In order to avoid that the kinetic energy stored in the rapidly rotating flywheel during the coupling process is momentarily absorbed by the electric drive rotating at a low speed,
A freewheel clutch is provided between the flywheel and the drive motor. However, this results in additional construction costs for the mechanical construction.

DE 35 42 650 A1 likewise describes the problem of the starting process of a loom. This publication also proposes increasing the rotational speed of the electric drive motor above the normal operating rotational speed when the clutch is opened before the starting process. For this purpose, a series of strategies have been described for adjusting or controlling high rotational speeds. In principle, the features described in this publication do not surpass the prior art described in the above-mentioned Federal Republic of Germany Patent No. 1535525. This publication further describes the use of a frequency-controlled motor as the drive machine, and with this motor the use of the two-speed electric motor described in the above-mentioned Federal Republic of Germany Patent No. 1535525 is easily realized. can. There is no further explanation in the above-mentioned publication. Rather, the disclosure of this publication is limited exclusively to the acceleration control of the drive machine and the regulation of high rotational speeds. During the operating process, when the loom is connected to a high-speed drive machine, the only difference in relation to the speed diagram is that the loom accelerates from standstill to the operating speed, while the drive machine accelerates from its high speed to the operating speed. It only describes the time period during which the loom is first decelerated to below the operating speed and then accelerated together with the loom back to the operating speed. This publication furthermore states that at correspondingly high chosen high idle speeds, so-called speed interruptions which fall below the operating speed are reduced or prevented.

This situation creates new problems in that a significant increase in the speed range requires high costs and power;
This should be avoided as much as possible. However, this problem cannot be solved by the above-mentioned publication. Here, we turn to the problem of adopting a freewheel as in the case of the above-mentioned patent publication. For example, it is not described how the above-mentioned time periods can be shortened and harmful interruptions in the rotational speed during the coupling process can be avoided even with a slight increase in the rotational speed.

[Problem that the invention seeks to solve]

Starting from the device described in German Patent No. 15 35 525 mentioned above, the object of the invention is to avoid as much as possible the constructional outlays required by planetary gears and freewheels, and to avoid the high cost in the second step. The aim is to shorten the time required for the drive to reach the rotational speed as much as possible.

[Means for solving problems]

According to the invention, this object is achieved by the measures specified in the characterizing part of claim 1.

〔Effect of the invention〕

A major feature of the present invention is that when starting the loom, the drive motor is released from the system during the period when the rotational speeds of the flywheel and the main shaft of the machine are assimilated, and the loom is operated exclusively by the flywheel. It is powered by energy. By temporarily disengaging the electric drive, i.e. the motor is not connected to the grid during the transition period and is not driven at either increased or reduced speed, the mechanical freewheel element and the planetary gear are removed. No equipment required. This operating state can occur in various drive machines operating in high and low speed ranges, namely frequency-controlled motors, pole-change motors or brushless DC motors. Since pole change motors can be easily switched between two different speeds, planetary gearing can also be dispensed with in some cases, but there are requirements regarding the freewheeling characteristics, which are nevertheless particularly high. There is a need to reduce the turn-on time for high speed operation. These two requirements are also achieved in accordance with the invention by using a pole-changing motor with the operating process according to claim 4.

In the case of a pole change motor, the ratio of adjustable rotational speeds is generally 1:2. However, in order to start the loom, it is not necessary to increase the rotational speed to twice the operating speed; an increase of, for example, 12 to 20% is sufficient.
Now, in accordance with the present invention, if a command is given to switch the pole change motor to a higher speed just before the loom is to be restarted, the higher speed desired for the loom coupling is short-lived while the motor is accelerating. There is no need to wait until the final speed is reached. Rather, the acceleration process can be interrupted earlier and a flywheel coupling introduced. The point at which the acceleration process is interrupted can be easily monitored or ascertained in any way, for example by measuring the rotational speed or rotational speed, or simply by means of a timing circuit based on empirical values, for example. In both cases, long sustained rotations with high rotational speeds during the time of defect elimination are avoided. The connection to the flywheel of the loom is introduced in a known manner by accelerating the pole change motor to an increased rotational speed. The motor itself is not immediately switched to its lower speed, but is first only temporarily released, ie the motor is disconnected from the grid and its windings are short-circuited.

In all embodiments of the invention, an assimilation of the rotational speeds of the flywheel and the loom main shaft takes place during the transition time, in which case the loom is driven exclusively by the stored energy of the flywheel. A special mechanical freewheel between the motor and the flywheel is therefore not required. Only after a certain delay time is the electric motor reconnected to the system and switched to a lower speed in order to continue driving the loom. The delay time is preferably selected such that the connection between the three-phase current system and the motor takes place immediately after the first reed collision. The delay between motor disengagement and re-engagement is automatically implemented according to various magnitudes. For example, the instantaneous rotation speed of the flywheel or the loom main shaft or the rotation angle of the loom can be easily determined and evaluated in order to issue a switching command for the delay time. However, it is also possible to employ an empirical value as a constant delay time in the switch for driving the motor. In this way, the instantaneous rotational speed of the loom, which has just been connected to the flywheel, can be increased to a value of more than 96% of the rated rotational speed in a short period of time, causing stripes on the fabric due to insufficient impact of the weft threads. will not occur. The present invention can be added to existing drive equipment at any time without requiring large expenditures. For example, a fully automatic drive with a microprocessor can also be used. Thus, for example, it is possible not only to stop the loom in the event of a fault, but also to provide for the acceleration, disengagement and switching of the motor and the coupling of the flywheel to proceed fully automatically after the fault has been eliminated.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

First, the overall structure will be explained with reference to the block diagram of FIG. W is a loom, its main axis H
only shown. During operation, the loom W must be driven by the main drive A, which is supplied with power from the grid in the usual manner. A three-phase current system N with a frequency of f1 is prepared as a system. It is connected to the system N via a switching switch U to the frequency converter F in its switching position 1 or directly to the main drive A in its switching position 3. In that case, the frequency converter F converts the system frequency f1 to a higher frequency f2. Frequency converters are well known and will not be described in detail here. The respective desired frequency f2 is adjusted in the frequency converter F. The switching switch U is driven by a relay S. The switching switch U has three operating positions, namely position 1, which connects the system N to the frequency converter F, and intermediate position 2, where there is no connection.
and a terminal position 3 for directly connecting the system N to the main drive A. In this exemplary embodiment, there are three operating stages corresponding to the three switching positions during the switching process. That is, the operating stage () in which the flywheel is electrically driven at a rotational speed higher than the rated rotational speed, and the operating stage () in which the flywheel is separated and released from its drive device by a start command and the loom is connected to the flywheel ( ), and an operating phase () in which the drive is normally supplied with power when the instantaneous rotational speed of the flywheel has fallen in the range of the rated rotational speed with a delay.

The main drive A drives a flywheel M via a transmission G, here shown as a belt transmission. This flywheel M
is connected to the main shaft H of the loom W via a clutch brake unit K. The formation of the main drive device A and the structure of the drive system from the motor of the main drive device A to the connection part to the loom W are already known, so there is no need to describe them in detail here. When the main drive device A is directly connected to the system N, the flywheel is driven at a rotational speed n1 using the system frequency f1, taking into account the structural circumstances of the motor and transmission. This rotation speed n1
corresponds to the rated rotational speed of the loom W during operation. On the other hand, when power is supplied to the main drive device A via the frequency converter F at a frequency f2, the flywheel is rotated at a rotational speed n2. Frequency f2 is the frequency
Since the rotation speed n2 is selected to be larger than f1, the rotation speed n2 is also larger than the rotation speed n1. In order to start the loom W from a standstill, a switch E is provided, which drives a relay S on the one hand and a clutch-brake unit K on the other hand.
Note that a signal generator, for example, a rotation angle generator D, can be arranged on the main shaft H of the loom W. This signal acts on the relay S, as can be seen from the dashed connection line.

In order to explain the effect of this arrangement, it is assumed that the loom W has been stopped, for example due to a breakdown, and the entire installation has been switched to the operating phase (). In that case, the loom W has a clutch brake unit K.
The motor is separated from the flywheel M and the main drive unit A by the motor, and is in a stationary state. By placing the switching switch U in position 1, the main drive A is supplied with power via the frequency converter F at a high frequency f2. As a result, the flywheel M is rotated without load at a correspondingly high frequency n2. This operating phase () is shown on the left side of FIG.

To start the loom W after removing the defects,
At time E1, switch E is actuated, thereby introducing an operating phase () which is very important for the advantageous switching process. In this case, the switching switch U is placed in intermediate position 2 and the main drive A is not supplied with power from the system N either directly or via the frequency converter F. That is, only the mechanical energy stored in the flywheel M acts. The clutch/brake unit K is also actuated by the switch E.
The flywheel M is connected to the main shaft H of the loom W. As shown in the diagram in Figure 2, the number of revolutions or rotational speed of the flywheel is indicated by the dashed line.
n' decreases from the no-load rotational speed n2, while the rotational speed or rotational speed n of the main shaft H of the loom W, indicated by a dashed line, increases. After complete coupling, both rotational speeds n and n' have the same value. No-load rotation speed n2
is selected to be large, the speed assimilation is approximately equal to the desired rated speed n1 for operation.
For example, within a range slightly below this rated value. In this way, the rotational speed of the loom up to the first reel impact is so high that the first weft thread is actually already impacted with full force, so that unsightly run-outs in the fabric are avoided. During the operating phase (), as already mentioned, no driving force acts on the flywheel other than the stored mechanical energy.

With a short delay time T1, preferably immediately after the first reed collision, the operating phase () ends at time E2 and the operating phase () is introduced.
For this purpose, the switching switch U is switched from its intermediate position 2 to its position 3, and the main drive A is switched directly to the line N.
connected to. As a result, at this stage of operation, the flywheel M and the main shaft H are rotated at the rated rotation speed.
Driven by n1. A subsequent second reed collision takes place with almost no reduction in force.

As already mentioned, the delay time T is determined as an empirical value. For this purpose, a delay circuit Z is shown in the relay S in FIG. When the relay S is activated by the switch E at the closing point E1, a delay circuit Z is activated at the same time, which causes the relay S to close the switching switch U from position 2 to position 3 after the set time has elapsed. It acts on Note that the method shown by the broken line in FIG. 1 is also possible. For example, the instantaneous rotation speed or rotation angle of the main shaft H is detected by the signal generator D, and is input to the relay S as a signal. By means of this signal, the switching switch U is switched between positions 2 and 3 in dependence on the rotational angle or rotational speed of the main shaft H. The required delay time can be easily determined and adjusted accordingly to the requirements. The operating stages (), (), () shown in FIG.
It corresponds to 2 and 3.

FIG. 3 shows an example in which a pole change motor is used. The flywheel and clutch brake unit are not shown here for the sake of simplicity, but their structure and operation are the same as in FIG. Various switching systems are known for pole number conversion motors. Among various switching methods, the Dahlander switching method has been selected here. P is a motor, and its operation at different rotational speeds is represented by 2p for high-speed rotational operation corresponding to two-pole switching, and 4p for low-speed rotational operation corresponding to four-pole switching. To drive 2p,
The motor P has a switch Sh and a winding connection terminal 2u,
It is connected to the systems L1, L2, and L3 via 2v and 2w. A switch Sn is provided for 4p operation in the low speed rotation range, and the winding connection terminals are indicated by symbols 1u, 1v, and 1w. The switch Sh for high-speed rotation and the switch Sn for low-speed rotation are operated via a relay S as necessary. This relay S is controlled by a control device St. This arrangement structure is designed so that the 4p operation at low speed rotation is adapted to the rated operation of the loom at the rotation speed n1.
In order to switch the motor P to high-speed operation in the 2p operation, the switch Sh is closed by the relay S, but it is shut off again after a short time period T2 has elapsed. During time period T2, acceleration is interrupted when the motor P does not reach its final rotation speed and reaches an instantaneous rotation speed n2 that is approximately 10 to 20% higher than the rated rotation speed n1, and the motor P is separated from the system and released. It has been selected to be At this moment, the flywheel is also separated from the drive motor P and connected to the loom in the manner described above. Similarly, the delay time mentioned above
After T1 has elapsed, the pole number changing motor P is connected to the grid again. In that case, the switch Sn is closed and the motor 4p is operated at the rated motion speed n1. The two delay times T1, T2, as already mentioned with reference to FIG. be done. Furthermore, a control device St is connected to the loom W in order to detect and control the state of the loom W (in a manner not detailed). An example of this control will be briefly described below.

(a) Starting of the loom is prevented, for example if a break in the second warp thread is not excluded by mistake in the event of a breakdown.

(b) Repeated touching of the start button also prevents high-speed switching to 2p operation.

(c) The loom may not be started if the motor is not protected.

During normal operation, motor P is in the low speed rotation range.
It is rotated at the rated rotation speed n1 according to the operating rotation speed of the loom in 4p operation. This rotational speed is maintained if the loom is disconnected from the drive and stationary in the event of a breakdown.

The rotational speed diagrams a and b in FIG. 4 show not only a short period of time for the starting of the loom, i.e. the original coupling process as explained in FIG. Indicates a long time period. In this diagram, each process is shown roughly and schematically for comparison purposes only and not as a practical scale.

The rotational speed diagram a in FIG. 4 shows the progress when the motor is frequency controlled using the method shown in FIG. The course of rotational speed n over time t is shown. n1
is the corresponding rated speed of the loom or motor during operation. n2 is the increased rotational speed during the starting process of the loom. The solid line shows the rotational speed profile of the frequency-controlled motor, and the dash-dotted line shows the rotational speed profile of the loom. On the left side of time E0, the loom is in normal operation, and the loom and drive motor are driven at the rated speed n1. Assuming that the fault begins at time E0, this automatically disconnects the loom from the drive motor and brings it to a standstill. In the operating phase () between time E0 and time E1, any faults or defects occurring are eliminated. During this time, the frequency control motor is automatically switched to a high frequency f2, accelerated to a high rotational speed n2 in a time period T2, and is supplied with power so that this rotational speed is continuously maintained. Time after defect elimination
At E1, a switching command is generated as described above to isolate the motor from the higher frequencies and release it from the grid. At the same time, as mentioned above, the flywheel is connected to the loom for starting. point in time
During this operating phase (), which lasts until E2, the loom accelerates and again reaches its rated speed, while the drive motor decelerates from a high speed n2 and finally likewise reaches the rated speed n1 range. reach. time zone
In this operating phase of T1 (), the motor remains disconnected from the grid. This state is indicated by a dashed rotational speed curve rather than a solid line. point in time
At E2, the motor is connected to the grid again at a lower frequency and is normally powered. The operating process () started at time E2 corresponds to normal operation, in which case the loom and motor are again driven at their rated speed n1.

The rotational speed diagram b in the lower part of FIG. 4 shows the corresponding course of action in the convertible pole motor according to FIG. Here again, the rotational speed profile of the drive motor is shown by a solid line, and the rotational speed profile of the loom is shown by a dash-dotted line. The dotted course in a subrange of the motor rotational speed indicates that the motor is disengaged in this range. This example also assumes that a failure occurs at time E0 and the loom is stopped. The drive motor whose number of poles can be changed maintains its operating state and continues to rotate at the rated rotation speed n1, that is, it is driven in a low speed range during 4p operation. During the entire time of the fault and its elimination, the rotational speed of the drive motor does not change. Time point E1
When a closing command is issued at
Since the motor is switched into operation, the motor is accelerated in the operating phase (a) between the times E1 and Ex. However, as described above, this process is interrupted after reaching the instantaneous rotational speed n2 or after a predetermined delay time T2 and before reaching the final rotational speed. At this point
In the operating phase (b) starting here at Tx, the starting of the loom takes place, as already reiterated, by coupling the flywheel to the loom. Furthermore, the drive motor is released and its rotational speed decreases again in accordance with the dotted pattern. The duration of this operating phase (b) is designated by T1 and is controlled as a constant adjusted delay time or as a function of the detected measured values. After this operating phase b, operating phase (c) begins at time E2. In this operating phase (c), the drive motor is again normally supplied with power from the grid,
The loom is rotated at its rated rotation speed n1, and the loom is also operated at its rated rotation speed. This operating phase (c) corresponds to normal operating conditions.

The major difference between the speed profiles of FIG. 4a and FIG. 4b is that, in the case of the frequency-controlled drive motor of FIG. 4a, in order to accelerate the motor to a high speed n2, a very long The time period T2' is required. Experience has shown that in practice the time period T2' in the case of frequency-controlled motors is several times longer than the time period T2 in the case of pole-change motors. The frequency-controlled motor cannot be accelerated at time E1 immediately after eliminating the fault, which occurs simultaneously at the beginning of the fault phase (1). This is because sufficient time is available. Frequency-controlled motors have the above-mentioned drawback that they have to rotate at an increased speed during the entire time of failure and its removal. On the other hand, it is a great advantage to employ a motor whose number of poles can be changed and whose acceleration time is very short, on the order of seconds.

The method of starting the loom by temporarily disengaging the motor can be used regardless of the reason why the loom has to be turned on, and in particular can be used for the first starting of the loom as well as for restarting it after a breakdown. In the event of a breakdown, the loom is automatically stopped and, depending on its design, the drive motor is either switched over to a higher rotational speed for the duration of the breakdown or continues to run at the rated rotational speed.

[Brief explanation of drawings]

Figure 1 is a block diagram for driving a loom by a frequency control motor, Figure 2 is a diagram showing the relationship between the rotation speed and time of the drive device and loom in Figure 1, and Figure 3 is Figure 4 is a block diagram for driving a loom by a motor that can change the number of poles, and Figure 4 shows a comparison of the relationship between the drive device in Figures 1 and 3, the rotation speed of the loom, and time. It is a line diagram. A: Drive device, B: Switch, F: Frequency converter, G: Transmission device, N: System, U: Switching switch,
P: Motor, Sh, Sn: Switch.

Claims (1)

[Claims] 1. The starting energy is primarily provided by an electrically movable flywheel which can be connected to the loom, in which case the flywheel is activated for the operation of the loom before the engagement of the clutch introduced by the switching command. starting a loom which is equipped with a main electric drive which is rotated at a higher rotational speed than the rated rotational speed determined by the clutch and whose flywheel is separated from the electric drive during a transition phase after engagement of the clutch; In this method, the electric drive is temporarily released by a switching command controlling the coupling, and the subsequent normal power supply to the electric drive is delayed until the instantaneous rotational speed of the flywheel reaches the rated rotational speed of the loom. A method of starting a loom equipped with a main electric drive, characterized in that it is carried out when the range is reduced. 2. Method according to claim 1, characterized in that an adjustable delay circuit is provided for the switch controlling the switching process to the normal power supply. 3. A method as claimed in claim 1 or 2, characterized in that, in the event of a breakdown and the loom is stopped, the electric drive is automatically switched to an increased rotational speed. 4. The starting energy is provided primarily by an electrically movable flywheel which can be connected to the loom, in which case the flywheel reaches the rated speed determined for the operation of the loom before the clutch is engaged, introduced by the switching command. In a method for starting a loom which is equipped with a main electric drive which is rotated at a high rotational speed compared to the main speed of the loom and is equipped with such a main electric drive that the flywheel is separated from the electric drive during a transition phase after engagement of the clutch, A pole-change electric motor is used as the drive device, and its low-speed rotation range corresponds to the rated rotation speed of the loom. (a) The motor is switched to high-speed rotation by a start command, and (b) the motor is (c) Interrupting the acceleration process of the motor by isolating the loom from the system and coupling the loom to the flywheel and at the same time temporarily releasing the motor; (c) subsequently bringing the motor to the required low speed with a delay; A method for starting a loom equipped with a main electric drive, characterized by switching to a rotation range and supplying regular power. 5 The switching process from operation stage (a) to operation stage (b) is
5. A method as claimed in claim 4, characterized in that it is carried out by means of an adjustable delay circuit after the switching command has been issued. 6. The starting energy is primarily provided by an electrically movable flywheel which can be coupled to the loom, in which case the flywheel reaches the rated speed determined for the operation of the loom before the clutch is engaged, introduced by the switching command. A switching command for controlling the coupling of looms equipped with a main electric drive which is rotated at a high rotational speed compared to the speed and in which the flywheel is separated from the electric drive during a transition phase after engagement of the clutch. The electric drive is temporarily released, and the subsequent regular power supply to the electric drive takes place after a delay when the instantaneous rotational speed of the flywheel falls to the range of the rated rotational speed of the loom. In a circuit for carrying out the method of starting with - The switching switch U connected to the unit K has an intermediate position 2 that interrupts both power supply paths to the main drive A, and furthermore, the switching switch U can switch from one terminal position 1 to any control method E. 1. A circuit for starting a loom, characterized in that it can be adjusted to an intermediate position 2 by means of a loom, and from there it can be automatically switched to the other end position 3 after a delay time T1. 7. The starting energy is primarily provided by an electrically movable flywheel which can be connected to the loom, in which case the flywheel reaches the rated speed determined for the operation of the loom before the clutch is engaged, introduced by the switching command. As main drive of a loom, a loom is equipped with a main electric drive which is rotated at a high rotational speed compared to the speed and in which the flywheel is separated from the electric drive during a transition phase after engagement of the clutch. A pole-change electric motor is used, whose low speed rotation range corresponds to the rated speed of the loom, and (a) the motor is switched to high speed rotation by a start command, and (b) the motor is isolated from the grid. (c) interrupting the acceleration process of the motor by connecting the loom to the flywheel and at the same time temporarily releasing the motor; (c) subsequently bringing the motor with a delay into the low speed range required for operation; In the circuit for carrying out the method of starting by switching and supplying regular power, the main electric drive device P, which can change the number of poles, is connected to the switch Sh,
Sn can be connected to the power supply system (L1, L2, L3) with two poles (2p) or four poles (4p) as required, and the switch connected to the clutch/brake unit is connected to the main drive. It has an intermediate position where the pole and quadrupole power supply paths are temporarily interrupted,
Furthermore, the switching switch can be adjusted from its four-pole end position to its two-pole end position by any control method, and from there it is automatically set free in two successive steps with a delay that can be adjusted each time. A circuit for starting a loom, characterized in that it can be switched to the end position of a quadrupole via an intermediate position. 8. The circuit according to claim 6 or 7, wherein the relay S that controls the switching switch U has a delay circuit Z. 9. The circuit according to claim 6 or 7, characterized in that it has a rotational speed measuring device for controlling the switching switch U. 10 Relay S that is influenced by signal generator D attached to main shaft H of the loom and controls switching switch U
7. The circuit according to claim 6, characterized in that the circuit comprises: 11. Circuit according to claim 7, characterized in that it has a relay for controlling the switching switch which is influenced by a signal generator attached to the shaft of the main electric drive. 12 The starting energy is primarily provided by an electrically movable flywheel which can be coupled to the loom, in which case the flywheel reaches the rated rotation determined for the operation of the loom before the engagement of the clutch introduced by the switching command. A switching command for controlling the coupling of looms equipped with a main electric drive which is rotated at a high rotational speed compared to the speed and in which the flywheel is separated from the electric drive during a transition phase after engagement of the clutch. The electric drive is temporarily released, and the subsequent regular power supply to the electric drive takes place after a delay when the instantaneous rotational speed of the flywheel falls to the range of the rated rotational speed of the loom. A circuit for starting a loom, characterized in that the main drive device is a brushless DC motor whose rotational speed can be controlled and which can be temporarily separated from the system. circuit.