CN214122770U - Step-down starting device of autotransformer - Google Patents
Step-down starting device of autotransformer Download PDFInfo
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- CN214122770U CN214122770U CN202120089387.8U CN202120089387U CN214122770U CN 214122770 U CN214122770 U CN 214122770U CN 202120089387 U CN202120089387 U CN 202120089387U CN 214122770 U CN214122770 U CN 214122770U
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Abstract
The embodiment of the utility model discloses auto transformer step-down starting drive, including auto transformer, the auto transformer high-voltage side drops into the power, and the auto transformer low-voltage side connects into the motor, and auto transformer's star point side is provided with two taps that have connect the switch, and motor and auto transformer high-voltage side connect to power bus through the switch respectively, and each switch connects to the controller respectively and comes on-line control closed and disconnection. The embodiment of the utility model provides a but online adjustment start multiple has advantages such as accurate, anti-interference strong, the reliability of control.
Description
Technical Field
The utility model relates to a motor starting technique especially relates to an autotransformer step-down starting drive.
Background
The step-down starting of the autotransformer is an important starting mode of the motor, and the autotransformer is used for reducing the starting voltage applied to a stator winding of the motor; after the motor is started, the motor is separated from the autotransformer, so that the motor normally moves under full pressure; the autotransformer is connected to the electric network at the high voltage side and to the electric motor at the low voltage side, and is provided with several taps with different voltage ratios for selection. The autotransformer step-down starting device can select different taps of the autotransformer according to the allowed starting current and the required starting torque to realize step-down starting, and can be used whether the stator winding of the motor adopts a Y or delta connection method, but has the defects, such as: poor on-line adjustability, complex wiring of a control circuit, more components and joints, difficult maintenance and the like. This results in a limited range of applicability of the autotransformer step-down starting apparatus for which an optimum design is necessary.
SUMMERY OF THE UTILITY MODEL
Not enough to prior art exists, the utility model discloses an aim at solves above-mentioned technical problem, has provided an autotransformer step-down starting drive.
In order to solve the above technical problem, embodiments of the present invention provide a technical solution as follows.
The utility model provides an auto transformer starting drive that steps down, includes auto transformer, and the auto transformer high-pressure side drops into the power, and the auto transformer low pressure side is connected into the motor, and auto transformer's star point side is provided with first taking a percentage and the second is taken a percentage, wherein: the motor is connected to a power bus through a first switch, the high-voltage side of the autotransformer is connected to the power bus through a second switch, the first tap is connected with a third switch, the second tap is connected with a fourth switch, and control ends of the first switch, the second switch, the third switch and the fourth switch are respectively connected to the controller so that the controller can control the star point of the autotransformer to be turned on and off on line.
Preferably, a first mutual inductor combination is connected between the first switches and the motor stator winding access end in series, and a second mutual inductor combination is connected between the second switch and the high-voltage side of the autotransformer in series.
Preferably, the first transformer combination comprises a first current transformer and a first zero sequence transformer which are connected in series, and the second transformer combination comprises a second current transformer and a second zero sequence transformer which are connected in series.
Preferably, the first current transformer is connected with the first switch, the first zero sequence transformer is connected with the motor stator winding access end, the second current transformer is connected with the second switch, and the second zero sequence transformer is connected with the high-voltage side of the autotransformer.
Preferably, a node between the first current transformer and the first zero sequence transformer is connected with a first arrester, a node between the first current transformer and the first zero sequence transformer is connected with a second arrester, and the first arrester and the second arrester are respectively grounded.
Preferably, a node between the first current transformer and the first zero sequence transformer is connected with a first bypass switch, a node between the first current transformer and the first zero sequence transformer is connected with a second bypass switch, and the first bypass switch and the second bypass switch are respectively grounded.
Preferably, a node between the first current transformer and the first zero sequence transformer is connected with a first live display, a node between the first current transformer and the first zero sequence transformer is connected with a second live display, and the first live display and the second live display are respectively grounded.
Preferably, the low-voltage side and high-voltage side transformation ratio of the third switch is K1, and the low-voltage side and high-voltage side transformation ratio of the fourth switch is K2, wherein K1 is more than or equal to 0.6 and less than or equal to K2 and less than or equal to 0.85.
Preferably, K1 and K2 are set to fixed values, respectively.
Preferably, the controller is a PLC.
Compared with the prior art, the utility model discloses autotransformer step-down starting drive is an use controllable high voltage autotransformer on-load voltage regulation step-down starting drive, and it can obtain following beneficial effect: (1) by using the controllers such as the PLC and the like, the overall reliability of the product can be improved, a large number of relays and connecting wires are reduced, the failure rate is reduced, the operation and the maintenance are simple, the control is accurate and timely, and the anti-interference performance is high; (2) the autotransformer adopts a double-tap star point structure, so that the on-load gear shifting adjustment starting multiple can be realized; (3) the advantages of the autotransformer and the solid soft start are combined, the on-line adjustable starting device has the advantages of being low in starting multiple, good in on-line adjustability and low in cost, and one-to-many starting can be expanded.
Drawings
Fig. 1 is a system diagram of the auto transformer step-down starting apparatus according to the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments, but it should not be construed that the scope of the present invention is limited to the embodiments described below.
Referring to fig. 1, a system structure of the autotransformer step-down starting apparatus according to the embodiment of the present invention is shown. The structure, operation and process are described in detail below.
As shown in fig. 1, the autotransformer step-down starting apparatus of the present embodiment is used for starting a starter motor Y1, and is composed of an autotransformer T1, a controller (preferably a programmable controller PLC), switches Q1, Q2, Q3 and Q4, current transformers TA1 and TA2, bypass switches J1 and J2, lightning arresters F1 and F2, live monitors H1 and H2, zero-sequence transformers T01 and T02, and the specific connection relationship is as shown in fig. 1.
Referring to fig. 1, the high voltage side of the autotransformer T1 of the present embodiment is powered, the low voltage side of the autotransformer T1 is powered by the motor Y1, and the star point side of the autotransformer T1 is provided with a first tap and a second tap, where: the motor Y1 is connected to a power bus M1 through a switch Q1, the high-voltage side of the autotransformer T1 is connected to a power bus M1 through a switch Q2, a switch Q3 is connected to a first tap, a switch Q4 is connected to a second tap, and control ends of the switches Q1, Q2, Q3 and Q4 are respectively connected to a controller, so that the controller controls the star point of the autotransformer T1 to be closed and opened on line. A current transformer TA1 and a zero sequence transformer T01 are sequentially connected in series between the switch Q1 and the stator winding access end of the motor Y1, and a bypass switch J1, a lightning arrester F1 and an electrified display H1 are connected between a node between the switch Q1 and the zero sequence transformer T01 in parallel; a current transformer TA2 and a zero sequence transformer T02 are sequentially connected between the switch Q2 and the high-voltage side of the autotransformer T1 in series, and a bypass switch J2, a lightning arrester F2 and a live display H2 are connected between a node between the switch Q2 and the zero sequence transformer T02 in parallel.
Referring to fig. 1, the working principle and working process of the autotransformer step-down starting device of the present embodiment are as follows: the autotransformer T1 star point side adopts double taps, and online switching is controlled by a PLC; the autotransformer T1 is connected with a power supply through a switch Q2, the low-voltage side is connected with the motor through a switch Q1, two taps on the star point side adopt a switch Q3 and a switch Q4, the on-off of two star points of the autotransformer T1 is controlled by a PLC on line, and the output voltage on the low-voltage side is dynamically controlled. In this embodiment, the PLC monitors the values of the starting current and the bus voltage through the AI card itself, and the PLC outputs the shift switching action in sequence after judging that the current and voltage reach the shift condition. The low-voltage side and high-voltage side transformation ratio of the switch Q3 is K1, the low-voltage side and high-voltage side transformation ratio of the switch Q4 is K2, and generally, K1 is more than or equal to 0.6 and less than or equal to K2 and less than or equal to 0.85.
Referring to fig. 1, the starting process of the autotransformer step-down starting apparatus is as follows. Before the motor is started, all the switches are in an off state. When starting, after the PLC receives a starting signal, the PLC gives an instruction to close the switch Q3 and selects a lower gear ratio K first1The star point of (1) is tapped; the PLC sends a command to close the switch Q2, the autotransformer outputs voltage to start the motor, and the starting end voltage is K1Un, starting current is K1 2And Ilr. In the starting process of the motor, the bus voltage starts to rise and the starting current is reduced along with the rise of the rotating speed, and the PLC sends out an instruction to open the switch Q3 and close the switch Q4 when judging that the conditions are met; at the same time, the higher transformation ratio K is replaced2The star point tap of the autotransformer increases the output voltage of the low-voltage side of the autotransformer to accelerate the starting. At this time, the voltage at the starting end is K2Un, starting current is K2 2And Ilr. After the motor is accelerated, when the PLC judges that the starting current and the bus voltage meet the conditions, the switch Q4 is firstly switched off, the autotransformer is in a short-time reactor running state, and the starting current is reduced to be close to the rated current; the switch Q1 is closed again and the switch Q2 is opened again, so that the motor is switched to the bypass through the undisturbed close type, and the starting is finished.
In the starting process, the whole starting process is more automatic and integrated under the participation of the PLC. And errors caused by manual judgment, relay setting and the like are reduced. In addition, the star point of the autotransformer is adjustable, and the terminal voltage of the motor is adjusted through online tap switching of the PLC in the starting process, so that the motor can be started in an accelerated manner in the latter half of the starting process.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make modifications and changes without departing from the spirit and scope of the present invention.
Claims (10)
1. The utility model provides an auto transformer starting drive that steps down, includes auto transformer, and the auto transformer high-pressure side drops into the power, and the auto transformer low-pressure side connects into the motor, its characterized in that, auto transformer's star point side is provided with first taking a percentage and the second is taken a percentage, wherein: the motor is connected to a power bus through a first switch, the high-voltage side of the autotransformer is connected to the power bus through a second switch, the first tap is connected with a third switch, the second tap is connected with a fourth switch, and control ends of the first switch, the second switch, the third switch and the fourth switch are respectively connected to the controller so that the controller can control the star point of the autotransformer to be turned on and off on line.
2. The autotransformer step-down starting apparatus of claim 1, wherein a first transformer combination is coupled in series between the first switches and the motor stator winding input, and a second transformer combination is coupled in series between the second switches and the high voltage side of the autotransformer.
3. The autotransformer step-down starting apparatus of claim 2, wherein the first transformer combination comprises a first current transformer and a first zero sequence transformer connected in series, and the second transformer combination comprises a second current transformer and a second zero sequence transformer connected in series.
4. The autotransformer step-down starting apparatus of claim 3, wherein a first current transformer is connected to the first switch, a first zero sequence transformer is connected to the motor stator winding input, a second current transformer is connected to the second switch, and a second zero sequence transformer is connected to the high voltage side of the autotransformer.
5. The autotransformer step-down starting apparatus according to claim 3, wherein a first arrester is connected to a node between the first current transformer and the first zero sequence transformer, a second arrester is connected to a node between the first current transformer and the first zero sequence transformer, and the first arrester and the second arrester are grounded, respectively.
6. The autotransformer step-down starting apparatus according to claim 3, wherein a first bypass switch is connected to a node between the first current transformer and the first zero-sequence transformer, a second bypass switch is connected to a node between the first current transformer and the first zero-sequence transformer, and the first bypass switch and the second bypass switch are grounded, respectively.
7. The autotransformer step-down starting apparatus according to claim 3, wherein a first live display is connected to a node between the first current transformer and the first zero sequence transformer, a second live display is connected to a node between the first current transformer and the first zero sequence transformer, and the first live display and the second live display are respectively grounded.
8. The autotransformer step-down starting apparatus of claim 1, wherein the third switch low-side to high-side transformation ratio is K1, and the fourth switch low-side to high-side transformation ratio is K2, wherein 0.6 ≦ K1 < K2 ≦ 0.85.
9. The autotransformer step-down starting apparatus of claim 8, wherein K1 and K2 are respectively set to fixed values.
10. The autotransformer step-down starting apparatus of any one of claims 1 to 9, wherein the controller is a PLC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120089387.8U CN214122770U (en) | 2021-01-13 | 2021-01-13 | Step-down starting device of autotransformer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120089387.8U CN214122770U (en) | 2021-01-13 | 2021-01-13 | Step-down starting device of autotransformer |
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| Publication Number | Publication Date |
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| CN214122770U true CN214122770U (en) | 2021-09-03 |
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| CN202120089387.8U Active CN214122770U (en) | 2021-01-13 | 2021-01-13 | Step-down starting device of autotransformer |
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| CN (1) | CN214122770U (en) |
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2021
- 2021-01-13 CN CN202120089387.8U patent/CN214122770U/en active Active
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