CA1197283A - Arrangement for rotor-frequency-dependent short- circuiting of rotor-series-resistances for driving - Google Patents
Arrangement for rotor-frequency-dependent short- circuiting of rotor-series-resistances for drivingInfo
- Publication number
- CA1197283A CA1197283A CA000418078A CA418078A CA1197283A CA 1197283 A CA1197283 A CA 1197283A CA 000418078 A CA000418078 A CA 000418078A CA 418078 A CA418078 A CA 418078A CA 1197283 A CA1197283 A CA 1197283A
- Authority
- CA
- Canada
- Prior art keywords
- frequency
- circuit
- rotor
- comparison
- rated
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
- B66B1/00—Control systems of elevators in general
- B66B1/24—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration
- B66B1/28—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical
- B66B1/30—Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration electrical effective on driving gear, e.g. acting on power electronics, on inverter or rectifier controlled 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
- H02P1/34—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 progressive reduction of impedance in secondary circuit
Landscapes
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Power Engineering (AREA)
- Tests Of Circuit Breakers, Generators, And Electric Motors (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Control Of Stepping Motors (AREA)
- Control Of Electric Motors In General (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
- Control Of Ac Motors In General (AREA)
- Motor And Converter Starters (AREA)
Abstract
A B S T R A C T
The invention relates to an arrangement for rotor-frequency-dependent short-circuiting of rotor-resistances for driv-ing motors, more particularly in the case of hoist motors. To this end use is made of a frequency-detecting/and converter unit and a rated-value pre-selector which are connected to a comparison-circuit which produces a short-circuiting command. The frequency-detecting and converter unit consists of a rotor-frequency-depend-ent gate-circuit which, in the open condition, releases a fixed reference frequency to a counter which, in turn, passes the counted periods of the reference-frequency, through a matrix-circuit such as an EPROM, as a digital rated rotor-frequency value, to a comparison-circuit, rated-value pre-selection being effected digitally by adjustable code-switches at the comparison-circuit.
The invention relates to an arrangement for rotor-frequency-dependent short-circuiting of rotor-resistances for driv-ing motors, more particularly in the case of hoist motors. To this end use is made of a frequency-detecting/and converter unit and a rated-value pre-selector which are connected to a comparison-circuit which produces a short-circuiting command. The frequency-detecting and converter unit consists of a rotor-frequency-depend-ent gate-circuit which, in the open condition, releases a fixed reference frequency to a counter which, in turn, passes the counted periods of the reference-frequency, through a matrix-circuit such as an EPROM, as a digital rated rotor-frequency value, to a comparison-circuit, rated-value pre-selection being effected digitally by adjustable code-switches at the comparison-circuit.
Description
133~
This invention relates to an arrangement for rotor- ~
frequency-dependent short~circuiting of rotor-series-resistances for driving motors, more particularly in the case of hoist motors, by means of a frequency-detecting and converter unit, a rated-value factor, and a comparison circuit for producing a short-circuitin~ command.
In one known arrangement of the above mentioned type, the frequency is detected by char~ing a capacitor which has to be charged at a specific voltage. In this case, the predetermined voltage corresponds to the frequency to be measured, i.e. in this case the rated value has to be adjusted by an expert, by means of potentiometers and external voltmeters. The rotor-frequency to be adjusted can not be reco~nized immediately from the ou-tside.
This requires an allocation list of the rotor-frequency for the voltage to be measured. In addition to this,aspecific internal resistance of the measurin~ instrument has to be maintained in order to ensure the allocation. ~oreover, in the case of such adjustments, the tolerances of the components in general must be taken into account.
According to the invention, therefore, an arrangment of the kind mentioned above is to be provided which will ensure simple and reliable adjustment of the rated value and thus more precise functioning of the arrangement as a whole. This is achieved in a simple manner in that the frequency-detecting and converter unit consists of a rotor-irequency-dependent gate-circuit which, in the open condition,releases a fixed reference-frequency to a counter which, in turn, passes the counted periods of the reference-frequency, through a matrix-circuit as a digital actual rotor-fre-quency value to the comparison circuit, rated-value pre-selection being effected digitally by means of adjustable code-switches at the comparison-circuit.
In order to be able to evaluate in the range of the actual value also, and more or less independently of tolerances in components such as capacitors and resistors, it is an advantage for the fixed reference-frequency to be produced by a quartz oscillator (reference-frequency generator). In order to be able to construct the arrangement according to the invention with a small number of components, especially as regards the matrix circuit, it is an advantage for the matrix circuit to be in the form of an EPROM (erasable programmable read only memory). The use of an EPROM also makes it possible to increase the reference-frequency. Increasing the reference-frequency permits more accurate relaying of the rotor-frequency from the matrix circuit, the EPROM having sufficient storage capacity available almost without additional cost. Increasing the reference-frequency makes it possible to obtain better resolution o-E the measurement results.
From the point of view of storage costs and the necessary accur-acy in detecting rotor frequencies, a reference-frequency of 5 kHz has been found advantageous. Since, when the driving motor is started up, undefinable frequency-mixtures arise in the rotor, which are unsuitable for evaluating the rotor frequency, it is an advantage for the short-circuiting command from the comparison-circuit (comparator) to be capable of being influenced by a delay-circuit. ~n order not to exceed the addressing-range of the matrix, it is an advantage for the number of counted reference-frequency periods to be limited to a m~i m~l value. Generally speaking, this m~im~l value will correspond to the number of reference-frequency periods during maximal openin~ of the gate circuit.
In order to avoid additional switching means, i.e. to be able to make use of already existing systems, it is an advantage for the frequency-detecting and converter unit, and the rated value pre-selector/ to be built up with the comparison-circuit as an additional component, into a stored-programme control.
An example of an embodiment according to the invention is described hereinafter in conjunction with the drawing attached hereto, the method of operation being explained in greater detail.
The arrangement, represented in the drawing as a block-wiring-dia~ram, ~or rotor-frequency-dependent short-circuiting of rotor-resistances fox driving motors, which is of major interest for hoists in particular, consists of a frequency-detecting unit 1 to which rotor-voltage 2 is fed. Converter unit 3 consists of a counter 4, a re~erence-frequency generator 5 and, in the present case, EMPROM 18. Digital rated-value pre-selector 6 consists, in this case, of four two-digit code-switches 7. The code-switches 7 are BCB (binary-coded-decimal) coded and are connected, through leads 8, to comparators 10. The actual value from EMPROM 18 is connected, through lines 9, to comparators 10. As soon as the actual value exceeds the rated value, comparators 10 release a signal to a decodin~ circuit 11 for bus-system 12 of a freely - 3 ~
programmable control such as that disclosed in the operating instructions for the SIMATIC S5-110 A automating unit.
According to the exemplary embodiment one value from the EMPROM 18 is compared with 4 values from the switches 7, e.g. the value 10 is connected to the comparators 10 via the EMPROM 18 and compared ~ith the values 41, 32, 05 and 99 given by the switches 7. When there is agreement, a signal is produced by the associated comparator 10. The decoder 11 has a multiplexer output, i.e. the outputs of the comparators 10 are interrogated one after the other via the subsequent stored programmable control. The pointer in the decoder 11 indicates which output, dependent on the stored programmable control, is being interrogated via the bus system 12.
A delay-circuit 13 provides for a delay in the initial command from decoding circuit 11, through the leads of bus-system 12 and through decoder 14, as a function of the switching state of the driving-motor switching units.
The arrangement according to the invention functions as follows: frequency-detecting unit 1 converts the line-voltage into a s~uare wave voltage. Input-current limiting of frequency-detecting unit 1 is effected by a choke 15. Voltage separation between the rotor--voltage and the voltage fed to the arrangement is effected by an optical coupler, not shown. In order to keep measurement errors as low as possible, the duration of a rotor-frequency period is measured from the beginning of one full wave to the beginning of the next full wave. Through an input 16, the rotor-voltage can be simulated by a frequency-generator, and this input can therefore be provided as a test inputO The output from - 4 ~
~97~33 frequency-detecting unit 1 is connected to the input to converter unit 3. This input-signal releases output 15 from the reference-frequency generator 5 in the manner of a gate-circuit, which makes it possible to count the number of pulses from the reference-frequency generator 5, by means of counter 4, according to one period of the rotor-voltage, i.e, the number of pulses is propor-tional to the period length. If the measurement results are to he obtained in Hertz, the measured length of the period must be con-verted into Hertz. In this examplary embodiment this is effected by passing the period-length, as an address, to an EMPROM memory 18. This memory location contains, in BCD code, the value of the frequency corresponding to the period length. Now this BCD-coded frequency appears on leads 9 and is compared with the rated value adjusted by code-switches 7 which is fed, through lines 8, to comparators 10. The comparator results are fed as signals to decoding circuit 11 which, in turn, passes them through bus-line 12 of the stored-programme control, possibly after a delay produced by delay-circuit 13, to -the switching equipment handling the short-circuiting of the rotor resistances.
The arrangement according to the invention makes it possible to obtain measurements which are practically independent of the tolerances of any capacitors or resistors. It also enables the user to adjust the rated ~alue effortlessly, without special knowledge, -training or difficulty. The assembly can be triggered directly through the bus-systems of known stored programme controls and may also be interrogated.
~ 5
This invention relates to an arrangement for rotor- ~
frequency-dependent short~circuiting of rotor-series-resistances for driving motors, more particularly in the case of hoist motors, by means of a frequency-detecting and converter unit, a rated-value factor, and a comparison circuit for producing a short-circuitin~ command.
In one known arrangement of the above mentioned type, the frequency is detected by char~ing a capacitor which has to be charged at a specific voltage. In this case, the predetermined voltage corresponds to the frequency to be measured, i.e. in this case the rated value has to be adjusted by an expert, by means of potentiometers and external voltmeters. The rotor-frequency to be adjusted can not be reco~nized immediately from the ou-tside.
This requires an allocation list of the rotor-frequency for the voltage to be measured. In addition to this,aspecific internal resistance of the measurin~ instrument has to be maintained in order to ensure the allocation. ~oreover, in the case of such adjustments, the tolerances of the components in general must be taken into account.
According to the invention, therefore, an arrangment of the kind mentioned above is to be provided which will ensure simple and reliable adjustment of the rated value and thus more precise functioning of the arrangement as a whole. This is achieved in a simple manner in that the frequency-detecting and converter unit consists of a rotor-irequency-dependent gate-circuit which, in the open condition,releases a fixed reference-frequency to a counter which, in turn, passes the counted periods of the reference-frequency, through a matrix-circuit as a digital actual rotor-fre-quency value to the comparison circuit, rated-value pre-selection being effected digitally by means of adjustable code-switches at the comparison-circuit.
In order to be able to evaluate in the range of the actual value also, and more or less independently of tolerances in components such as capacitors and resistors, it is an advantage for the fixed reference-frequency to be produced by a quartz oscillator (reference-frequency generator). In order to be able to construct the arrangement according to the invention with a small number of components, especially as regards the matrix circuit, it is an advantage for the matrix circuit to be in the form of an EPROM (erasable programmable read only memory). The use of an EPROM also makes it possible to increase the reference-frequency. Increasing the reference-frequency permits more accurate relaying of the rotor-frequency from the matrix circuit, the EPROM having sufficient storage capacity available almost without additional cost. Increasing the reference-frequency makes it possible to obtain better resolution o-E the measurement results.
From the point of view of storage costs and the necessary accur-acy in detecting rotor frequencies, a reference-frequency of 5 kHz has been found advantageous. Since, when the driving motor is started up, undefinable frequency-mixtures arise in the rotor, which are unsuitable for evaluating the rotor frequency, it is an advantage for the short-circuiting command from the comparison-circuit (comparator) to be capable of being influenced by a delay-circuit. ~n order not to exceed the addressing-range of the matrix, it is an advantage for the number of counted reference-frequency periods to be limited to a m~i m~l value. Generally speaking, this m~im~l value will correspond to the number of reference-frequency periods during maximal openin~ of the gate circuit.
In order to avoid additional switching means, i.e. to be able to make use of already existing systems, it is an advantage for the frequency-detecting and converter unit, and the rated value pre-selector/ to be built up with the comparison-circuit as an additional component, into a stored-programme control.
An example of an embodiment according to the invention is described hereinafter in conjunction with the drawing attached hereto, the method of operation being explained in greater detail.
The arrangement, represented in the drawing as a block-wiring-dia~ram, ~or rotor-frequency-dependent short-circuiting of rotor-resistances fox driving motors, which is of major interest for hoists in particular, consists of a frequency-detecting unit 1 to which rotor-voltage 2 is fed. Converter unit 3 consists of a counter 4, a re~erence-frequency generator 5 and, in the present case, EMPROM 18. Digital rated-value pre-selector 6 consists, in this case, of four two-digit code-switches 7. The code-switches 7 are BCB (binary-coded-decimal) coded and are connected, through leads 8, to comparators 10. The actual value from EMPROM 18 is connected, through lines 9, to comparators 10. As soon as the actual value exceeds the rated value, comparators 10 release a signal to a decodin~ circuit 11 for bus-system 12 of a freely - 3 ~
programmable control such as that disclosed in the operating instructions for the SIMATIC S5-110 A automating unit.
According to the exemplary embodiment one value from the EMPROM 18 is compared with 4 values from the switches 7, e.g. the value 10 is connected to the comparators 10 via the EMPROM 18 and compared ~ith the values 41, 32, 05 and 99 given by the switches 7. When there is agreement, a signal is produced by the associated comparator 10. The decoder 11 has a multiplexer output, i.e. the outputs of the comparators 10 are interrogated one after the other via the subsequent stored programmable control. The pointer in the decoder 11 indicates which output, dependent on the stored programmable control, is being interrogated via the bus system 12.
A delay-circuit 13 provides for a delay in the initial command from decoding circuit 11, through the leads of bus-system 12 and through decoder 14, as a function of the switching state of the driving-motor switching units.
The arrangement according to the invention functions as follows: frequency-detecting unit 1 converts the line-voltage into a s~uare wave voltage. Input-current limiting of frequency-detecting unit 1 is effected by a choke 15. Voltage separation between the rotor--voltage and the voltage fed to the arrangement is effected by an optical coupler, not shown. In order to keep measurement errors as low as possible, the duration of a rotor-frequency period is measured from the beginning of one full wave to the beginning of the next full wave. Through an input 16, the rotor-voltage can be simulated by a frequency-generator, and this input can therefore be provided as a test inputO The output from - 4 ~
~97~33 frequency-detecting unit 1 is connected to the input to converter unit 3. This input-signal releases output 15 from the reference-frequency generator 5 in the manner of a gate-circuit, which makes it possible to count the number of pulses from the reference-frequency generator 5, by means of counter 4, according to one period of the rotor-voltage, i.e, the number of pulses is propor-tional to the period length. If the measurement results are to he obtained in Hertz, the measured length of the period must be con-verted into Hertz. In this examplary embodiment this is effected by passing the period-length, as an address, to an EMPROM memory 18. This memory location contains, in BCD code, the value of the frequency corresponding to the period length. Now this BCD-coded frequency appears on leads 9 and is compared with the rated value adjusted by code-switches 7 which is fed, through lines 8, to comparators 10. The comparator results are fed as signals to decoding circuit 11 which, in turn, passes them through bus-line 12 of the stored-programme control, possibly after a delay produced by delay-circuit 13, to -the switching equipment handling the short-circuiting of the rotor resistances.
The arrangement according to the invention makes it possible to obtain measurements which are practically independent of the tolerances of any capacitors or resistors. It also enables the user to adjust the rated ~alue effortlessly, without special knowledge, -training or difficulty. The assembly can be triggered directly through the bus-systems of known stored programme controls and may also be interrogated.
~ 5
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An arrangement for rotor-frequency-dependent short-circuiting of rotor-series-resistances for driving motors by means of a frequency-detecting and converter unit, a rated-value pre-selector, and a comparison-circuit which produces a short-circui-ting command, characterized in that the frequency-detecting and converter unit consists of a rotor-frequency-dependent gate cir-cuit which, in the open condition, releases a fixed reference-frequency to a counter which, in turn, passes the counted periods of the reference-frequency through a matrix-circuit as a digital actual rotor-frequency value, to the comparison-circuit, rated-value pre-selection being effected digitally by adjustable code-switches at the comparison-circuit.
2. An arrangement according to claim 1, characterized in that the fixed reference-frequency is produced by a quartz oscillator.
3. An arrangement according to claim 1 or 2, characterized in that the matrix-circuit is formed by an EPROM (erasable pro-grammable read only memory).
4. An arrangement according to claim 2, characterized in that the reference-frequency amounts to 5 kHz.
5. An arrangement according to claim 4, characterized in that the short-circuiting command from the comparison-circuit is adapted to be influenced by a delay circuit.
6. An arrangement according to claim 1, 2 or 5 characterized in that the frequency-detecting and converter unit and the rated value pre-selector is built-up, with the comparison-circuit, to form a stored-programme control.
7. An arrangement according to claim 1, 2 or 5 characterized in that the number of counted periods of the reference-frequency is limited to a maximal value.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3150570A DE3150570C2 (en) | 1981-12-21 | 1981-12-21 | Arrangement for the rotor frequency-dependent short-circuiting of the rotor series resistors for drive motors |
| DEP3150570.8 | 1981-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1197283A true CA1197283A (en) | 1985-11-26 |
Family
ID=6149290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000418078A Expired CA1197283A (en) | 1981-12-21 | 1982-12-20 | Arrangement for rotor-frequency-dependent short- circuiting of rotor-series-resistances for driving |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0084109B1 (en) |
| AT (1) | ATE19166T1 (en) |
| AU (1) | AU9166082A (en) |
| CA (1) | CA1197283A (en) |
| DE (1) | DE3150570C2 (en) |
| DK (1) | DK561382A (en) |
| ZA (1) | ZA829336B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4410959C2 (en) * | 1994-03-29 | 1999-04-15 | Siemens Ag | Process for starting a slip ring motor |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1108393B (en) * | 1955-09-20 | 1961-06-08 | Siemens Ag | Device for a three-phase loop rotor motor for conveyor machine drives to initiate the rotor short circuit when a specified speed is reached |
| DE1906383C3 (en) * | 1969-02-08 | 1975-11-13 | Siemens Ag | Device for speed control of three-phase slipring motors for crane hoists or trolleys |
| DE2153228A1 (en) * | 1971-10-26 | 1973-05-03 | Bosch Elektronik Gmbh | DIGITAL CIRCUIT ARRANGEMENT |
| US3772579A (en) * | 1972-09-11 | 1973-11-13 | Harnischfeger Corp | Control means for high speed hoist |
-
1981
- 1981-12-21 DE DE3150570A patent/DE3150570C2/en not_active Expired
-
1982
- 1982-12-03 AT AT82111202T patent/ATE19166T1/en not_active IP Right Cessation
- 1982-12-03 EP EP82111202A patent/EP0084109B1/en not_active Expired
- 1982-12-20 AU AU91660/82A patent/AU9166082A/en not_active Abandoned
- 1982-12-20 CA CA000418078A patent/CA1197283A/en not_active Expired
- 1982-12-20 DK DK561382A patent/DK561382A/en not_active Application Discontinuation
- 1982-12-20 ZA ZA829336A patent/ZA829336B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ATE19166T1 (en) | 1986-04-15 |
| DE3150570A1 (en) | 1983-07-14 |
| DK561382A (en) | 1983-06-22 |
| DE3150570C2 (en) | 1983-10-27 |
| EP0084109B1 (en) | 1986-04-09 |
| ZA829336B (en) | 1983-09-28 |
| EP0084109A1 (en) | 1983-07-27 |
| AU9166082A (en) | 1983-06-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |