GB2110488A - Control circuit for a short- circuit rotor asynchronous motor with commutable poles - Google Patents
Control circuit for a short- circuit rotor asynchronous motor with commutable poles Download PDFInfo
- Publication number
- GB2110488A GB2110488A GB08234389A GB8234389A GB2110488A GB 2110488 A GB2110488 A GB 2110488A GB 08234389 A GB08234389 A GB 08234389A GB 8234389 A GB8234389 A GB 8234389A GB 2110488 A GB2110488 A GB 2110488A
- Authority
- GB
- United Kingdom
- Prior art keywords
- motor
- polar
- rotational speed
- circuit
- windings
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
- H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
- H02P3/18—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing an ac motor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
- H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
- H02P1/26—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual polyphase induction motor
- H02P1/38—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual polyphase induction motor by pole-changing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/24—Controlling the direction, e.g. clockwise or counterclockwise
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
- H02P25/20—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays for pole-changing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Stopping Of Electric Motors (AREA)
- Control Of Ac Motors In General (AREA)
- Control Of Electric Motors In General (AREA)
- Induction Machinery (AREA)
Abstract
The circuit provides reversal of rotation, a smooth start and electric braking and includes means by which both the starting torque and accelerating process are able to be controlled, and also braking can take place electrically with variable moment. A circuit includes an electronic switch (2) connected in series to at least one phase of the motor windings (1), and controlled such that during starting the forward flow angle, following a time- dependent function, rises from an adjustable initial value up to the full value of the sine half wave, such control being linked by an instrument (4) to the rotational speed of the motor to cause a switchover from the high-polar windings to the low-polar winding, on reaching the high-polar rotational speed. On switchover from the low-polar windings to the high- polar windings in the braking process, the forward flow angle from the switch (2) is limited to the set initial value and is then increased dependent on time. <IMAGE>
Description
SPECIFICATION
Short-circuit rotor asynchronous motor with commutable poles
The invention relates to a short-circuit rotorasynchronous motor with commutable poles, particularly to those of the type with reversal of rotation, smooth starting and electric braking.
Short-circuit rotor motors are particularly advantageous for many applications, owing to the simple construction and the minimal maintenance costs. The possibilities of application can be further increased through devices which enable the acceleration and braking process to be controlled. Devices are known, which reduce the starting torque of the motor in that the stator winding in one or several phases is supplied by way of a resistor connected in -series. These socalled smooth starting resistors are shortcircuited again after the start-up time, so that the motor can emit its full-power output. The same purpose is fulfilled by phase commencement controls, which during the start-up phase limit the forward flow angle in the controlled phases.
The high starting currents and the losses involved in the above devices, are undesirable in the short-circuit rotor motor.
In short-circuit rotor motors with commutable poles, the losses can be reduced and the output capacity of the motor can be better utilized in that the motor always in the first instance accelerates with the high-polar winding to the low synchronous rotational speed and then with the low-polar winding accelerates up to the high rotational speed.
In order to brake a short-circuit rotor asynchronous motor electrically, the countertorque control can be applied or in motors with commutable poles the generator braking for the deceleration to the slow rotational speed can be applied. Since in particular the generator brake torque is very great, this method cannot be used in most cases, so that instead of the generator electric braking, a mechanical brake is used, in order to decelerate the motor to the synchronous rotational speed of the high-polar winding, resulting in an additional effort in determining the point of time at which the high-polar winding must again be connected in. In place of the mechanical brake, methods are also known here in which the stator winding is energized with a constant field, which executes the braking effect.
However, this solution is very costly owing to the devices for the supply and control of the necessary constant field. A mechanical brake is disadvantageous because of its wear and the related maintenance costs. In addition, a mechanical brake is very greatly dependent, on environmental influences (temperature, air humidity, deposit of foreign substances) and the duration of operation, so that there is little reproducibility of the brake process over a longer period.
In many transport, conveying and travelling applications, a non-jerky start and acceleration and a non-jerky braking and, in connection with positioning processes, also an exactly reproducible braking behaviour is required.
Although two engine speeds are sufficient for these applications, in many cases the low-priced short-circuit rotor motor with commutable poles cannot be used for this because it does not fulfil the requirements concerning starting and braking behaviour, so that more expensive solutions with slip-ring rotor motors and direct-current motors have to be selected.
The present invention seeks to equip a shortcircuit rotor motor, with commutable poles, with economic means by which both starting torque and acceleration can be controlled, by which braking can be carried out electrically with a variable moment. The invention provides a circuit for a short-circuit rotor asynchronous motor with commutable poles, in which an electronic switch is connected in series to at least one phase of the motor windings, and controlled such that during starting the forward flow angle, following a timedependent function, rises from an adjustable initial value up to the full value of the sine half wave, such control being linked to the rotational speed of the motor to cause a switchover from the high-polar windings to the low-polar windings, on reaching the high-polar rotational speed, and on switchover from the low-polar to the high-polar windings in the braking process, to limit the forward flow angle from the switch to the set initial value and then to increase it dependent on time.
In preferred circuits of the invention the electronic switch is a triac, and the control is effected with the use of a control instrument coupled to an impulse for supplying impulses proportional to the rotational speed of the motor.
It is also preferred that the circuit includes hand switches constructed as sequence closers and associated with the two directions of rotation, which cooperates with a counter barrier, dependent on direction of rotation for monitoring the rotational speed of the motor.
In the use of a circuit of the invention, the initial value of the forward flow angle defines the starting torque, which depending on the setting selected can be reduced up to approximately 20% of the nominal starting torque. The timedependent adjustment of the forward flow angle brings it about that the motor, even when the initial break-away torque is greater than the set starting torque, is only on short-circuit for a short period of time, and then begins to rotate, and likewise through this time-dependent function the dynamics of the starting process can be altered.
The accleration of the motor from a standstill always takes place with the high-polar winding; this is ensured in preferred embodiments by a control logic which receives one or more electrical impulses per revolution of the motor shaft from an impulse transmitter, and from this information on rotational speed diverts the switching command to the low-polar winding. In contrast to conventional starting circuits with control of the pole changing through a timing relay, the control dependent on rotational speed ensures that the time for switchover, even with inching service and interrupted braking process or alternating load moments, is always exactly met.
After switchover to the low-polar winding, the subsequent acceleration process should commence as much as possible without jerks.
This is achieved in that after the pole changing to the low-polar winding the electronic switch again limits the forward flow angle in one or more phases to an initial value and subsequently increases it, dependent on time. In connection with the control, dependent on rotational speed, of the point of time for changeover, it is possible in this way, on acceleration, to set the switchover rotational speed and initial forward flow angle such that both windings at the point of time for switchover produce the same torque. On acceleration from the constant rotational speed of the high-polar winding, the initial value of the forward flow angle can be set such that the accelerating moment proceeding from a very small initial value, rises dependent on time, so that the accelerating process commences very softly.
Using a circuit according to the invention, the following conditions are therefore simultaneously fulfilled for the starting of the short-circuit rotor motor with commutable poles:
1. Gentle application of acceleration from rest and from the high-polar rotational speed;
2. Decrease in losses and reduction in starting currents through compulsory acceleration below the high-polar rotational speed with the highpolar winding;
3. Jerk-free transition of the acceleration process on switchover from the high-polar to the low-polar winding also under changing operating conditions.
The electric braking of the short-circuit rotor motor with countercurrent produces a high initial brake torque and produces very great power losses in the rotor, so that in order to reduce the high initial moment additional measures are necessary and the permissible frequency of the braking processes is small owing to the thermal load of the rotor. The generator braking produces, by way of comparison, 1/5 of this power loss in the rotor, but produces an even greater initial brake torque than the countertorque control. The arrangement according to the invention avoids this disadvantage of the generator braking, by the electronic switch already described limiting the forward flow angle to the set initial value on commencement of the braking process through putting into circuit the high-polar winding, and thereby reducing the generator brake torque.
The generator moment can be controlled depending on the desired motor characteristic curve through constant or variable forward flow angle in order to become zero on synchronous rotational speed, so that the deceleration takes place with a reduced generator moment and a jerk-free transition into the rotational speed of the high-polar winding occurs. Compared with the mechanical brake or with a different electric braking process, the arrangement according to the invention has the additional advantage that no braking time or rotational speed has to be determined in order to put into circuit again the high-polar winding after the braking process.If the motor is to be decelerated to a standstill, then through the control logic generator braking takes place compulsorily up to the rotational speed of the high-polar winding in the manner described and then from the measured rotational speed the point of time for switchover is divereted to the mechanical brake. In this it is again possible to select the switchover rotational speed such that at the point in time for switchover generator brake torque and mechanical brake torque are of equal extent. The determination of rotational speed of the motor therefore serves for the establishment of the upper point of rotational speed for the acceleration with the high-polar winding and for the engaging of the mechanical brake.It is an advantage of the invention that the determination of rotational speed can also be used for this, in order to prevent countertorque braking in reversible motors. This is achieved in that an additional rotational speed value is monitored in the proximity of standstill, so that only after falling below this rotational speed can the opposite direction of rotation be engaged.
An embodiment of the invention is represented in the accompanying drawing by way of example.
The circuit illustrated consists of a short-circuit rotor motor with commutable poles 1, an electronic switch or triac 2 for the control of phase commencement, an impulse transmitter 3 for the determination of rotational speed on the motor, a control instrument 4, electro-mechanical switches 5 for the two directions of rotation and switches 6 for the two rotational speeds of the motor and hand switches 7 and 8 for the presetting of direction of rotation and rotational speed by an operator. The motor circuit is supplied via connections 9 and the control circuit via connections 10. The impulse transmitter 3 is connected with the motor shaft 11. The electrical initial signal of the impulse transmitter 3 is passed to the control instrument 4 via the connection 17.
The control instrument 4 controls via connection 12 the ignition angle of the electronic switch 2, via connection 13 the switch for the low rotational speed, via connection 14 the switch for the high rotational speed, via connection 1 5 the switch for the first direction of rotation and via connection 1 6 the switch for the counter direction. The control instrument receives the command for the first direction of rotation via connection 1 8 and for the counter direction via connection 19 and a command common to both directions of rotation for the high rotational speed via connection 20.
In the example represented, the motor is controlled in the first direction of rotation with the switch 7; e.g., by an operator. In the function as sequence contact, this switch produces in the first operating position the command "slow rotational speed" for the control instrument, which detects the rotational speed from the impulse transmitter 3 and, if the threshold value for a counter barrier is falled short of, raises the counter barrier and actuates via connection 1 5 the electromechanical switch 5 for the first direction of rotation and via connection 13 the electromechanical switch 6 for the slow rotational speed, and also via connection 12 controls the forward flow angle of the electronic switch, proceeding from the set initial value, following a pre-set time function, so that the motor accelerates with a reduced starting torque.Even if the switch 7 is brought into the second operating position by the operator, the acceleration process takes place in the same way up to the set upper rotational speed value for the acceleration with the high-polar winding and is subsequently continued such that the control instrument, via connection 14 and the switch 6, puts into circuit the low-polar winding and via 1 3 and 6 disconnects the high-polar winding. In this, at the same time, the forward flow angle of the electronic switch 2 is reduced by the control instrument 4 to the initial value, so that the acceleration process is continued with the reduced moment. A subsequent braking process can be released by the operator in that the switches the switch 7 back into its first operating position.The control instrument 4 detects this new command and puts into circuit again, via connection 13 and the switch 6 the high-polar winding, whereby at the same time the forward flow angle of the electronic switch 2 is reduced to the initial value and the low-polar winding is disconnected, so that a reduced generator moment brakes the motor up to the rotational speed of the high-polar winding.
Following a time function, thereby the forward flow angle is again increased up to the full sine half wave. If the braking process is released in that the switch 7 again switches back into its idle position, then the braking process runs until the set lower rotational speed value for the electric braking is reached, also in the manner described above, subsequently the control instrument 4 disconnects the high-polar winding of the motor 1 via the connection 13 and the switch 6 and also the first direction of rotation via the connection 1 5 and the switch 5, so that the mechanical brake becomes effective. For the counter barrier the control instrument continues to store the last direction of rotation put into circuit.
If the starting process is interrupted, the mechanical brake becomes effective below the rotational speed value for the electric braking and above it the generator electric braking is put into circuit such that always the forward flow angle at the electronic switch 2 is reduced to the initial value.
If the braking process is interrupted, then below the upper rotational speed value for the high-polar winding for acceleration the high-polar winding is put into circuit, and above it, the lowpolar winding. With the newly commencing acceleration process always the forward flow angle at the electronic switch 2 is reduced to the initial value.
The operation cycles described for the first direction of rotation are repeated in a corresponding manner for the opposite direction, if instead of the hand switch 7 the hand switch 8 is actuated.
Claims (4)
1. A circuit for a short-circuit rotor asynchronous motor with commutable poles, in which an electronic switch is connected in series to at least one phase of the motor windings, and controlled such that during the forward flow angle, following a time-dependent function, rises from an adjustable initial value up to the full value of the sine half wave, such control being linked to the rotational speed of the motor to cause a switchover from the high-polar windings to the low-polar windings, on reaching the high-polar rotational speed1 and on switchover from the lowpolar to the high-polar windings in the braking process, to limit the forward flow angle from the switch to the set initial value and then to increase it dependent on time.
2. A circuit according to Claim 1 wherein the electronic switch is a triac, and wherein said control is effected with the use of a control instrument coupled to an impulse for supplying impulses proportional to the rotational speed of the motor.
3. A circuit according to Claim 1 or Claim 2 including hand switches constructed as sequence closers and associated with the two directions of rotation, which cooperate with a counter barrier, dependent on direction of rotation for monitoring the rotational speed of the motor.
4. A circuir for a short-circuit asynchronous motor with commutable poles, substantially as described herein with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3148311 | 1981-12-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2110488A true GB2110488A (en) | 1983-06-15 |
Family
ID=6148053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08234389A Withdrawn GB2110488A (en) | 1981-12-02 | 1982-12-02 | Control circuit for a short- circuit rotor asynchronous motor with commutable poles |
Country Status (3)
| Country | Link |
|---|---|
| FR (1) | FR2517490A1 (en) |
| GB (1) | GB2110488A (en) |
| IT (1) | IT1153058B (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0124698A1 (en) * | 1983-03-15 | 1984-11-14 | Diegner & Schade Inh. J. Thäter | Speed regulated motor drive |
| FR2697387A1 (en) * | 1992-10-28 | 1994-04-29 | Bodet Pierre | Device for maintaining an alternating or pendulum movement. |
| DE4242665A1 (en) * | 1992-12-17 | 1994-06-23 | Sew Eurodrive Gmbh & Co | Method and device for switching down a pole-changing motor |
| US5413050A (en) * | 1993-08-18 | 1995-05-09 | Maki; Nagatoshi | Pattern controller used with shotshell |
| WO2000077921A1 (en) * | 1999-06-10 | 2000-12-21 | General Electric Company | Speed reduction switch |
| EP1492221A1 (en) * | 2003-06-27 | 2004-12-29 | Demag Cranes & Components GmbH | Drive assembly, in particular for a lifting device and/or for a vehicle propulsion |
| RU2497267C1 (en) * | 2012-05-11 | 2013-10-27 | Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Уральский университет имени первого Президента России Б.Н. Ельцина" | Method of smooth start of asynchronous motor with squirrel-cage rotor |
| CN103560631A (en) * | 2013-11-01 | 2014-02-05 | 景德镇市景德电机有限公司 | Low-rotation speed multiple-speed three-phase asynchronous motor |
| RU2625807C2 (en) * | 2016-01-14 | 2017-07-19 | Евгений Борисович Колесников | Method of smooth start of asynchronous motor with squirrel-cage rotor |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1563207B1 (en) * | 1966-12-24 | 1970-02-26 | Holzer Patent Ag | Arrangement for pole-changing motors in washing machines |
| ES358002A1 (en) * | 1967-09-15 | 1970-04-01 | Honsberg Geb | Three phase motor with a device for its maneuver without contacts. (Machine-translation by Google Translate, not legally binding) |
| SE303362B (en) * | 1967-11-24 | 1968-08-26 | Asea Ab | |
| DE1781088A1 (en) * | 1968-08-22 | 1970-10-22 | Licentia Gmbh | Hoist drive with voltage-gate controlled Kaefiglaeufermotor |
| US3716770A (en) * | 1970-04-20 | 1973-02-13 | Reliamatic Inc | Slow start-stop motor control system |
| FR2313300A1 (en) * | 1975-03-20 | 1976-12-31 | Otis Ascinter | ELEVATOR MOTOR CONTROL SYSTEM |
-
1982
- 1982-10-26 FR FR8217913A patent/FR2517490A1/en not_active Withdrawn
- 1982-11-17 IT IT24299/82A patent/IT1153058B/en active
- 1982-12-02 GB GB08234389A patent/GB2110488A/en not_active Withdrawn
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0124698A1 (en) * | 1983-03-15 | 1984-11-14 | Diegner & Schade Inh. J. Thäter | Speed regulated motor drive |
| FR2697387A1 (en) * | 1992-10-28 | 1994-04-29 | Bodet Pierre | Device for maintaining an alternating or pendulum movement. |
| BE1007647A3 (en) * | 1992-10-28 | 1995-09-05 | Bodet Pierre | Piece device for maintaining a reciprocating or pendulum. |
| DE4242665A1 (en) * | 1992-12-17 | 1994-06-23 | Sew Eurodrive Gmbh & Co | Method and device for switching down a pole-changing motor |
| DE4242665B4 (en) * | 1992-12-17 | 2005-12-29 | Sew-Eurodrive Gmbh & Co. Kg | Method and device for switching back a pole-changing motor |
| US5413050A (en) * | 1993-08-18 | 1995-05-09 | Maki; Nagatoshi | Pattern controller used with shotshell |
| WO2000077921A1 (en) * | 1999-06-10 | 2000-12-21 | General Electric Company | Speed reduction switch |
| EP1492221A1 (en) * | 2003-06-27 | 2004-12-29 | Demag Cranes & Components GmbH | Drive assembly, in particular for a lifting device and/or for a vehicle propulsion |
| US7068009B2 (en) | 2003-06-27 | 2006-06-27 | Demag Cranes & Components Gmbh | Drive arrangement, especially for a lifting mechanism and/or a traveling drive |
| RU2497267C1 (en) * | 2012-05-11 | 2013-10-27 | Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Уральский университет имени первого Президента России Б.Н. Ельцина" | Method of smooth start of asynchronous motor with squirrel-cage rotor |
| CN103560631A (en) * | 2013-11-01 | 2014-02-05 | 景德镇市景德电机有限公司 | Low-rotation speed multiple-speed three-phase asynchronous motor |
| RU2625807C2 (en) * | 2016-01-14 | 2017-07-19 | Евгений Борисович Колесников | Method of smooth start of asynchronous motor with squirrel-cage rotor |
Also Published As
| Publication number | Publication date |
|---|---|
| IT8224299A1 (en) | 1984-05-17 |
| IT1153058B (en) | 1987-01-14 |
| FR2517490A1 (en) | 1983-06-03 |
| IT8224299A0 (en) | 1982-11-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |