CN219107328U - Transformer slow start circuit and device - Google Patents
Transformer slow start circuit and device Download PDFInfo
- Publication number
- CN219107328U CN219107328U CN202223570416.6U CN202223570416U CN219107328U CN 219107328 U CN219107328 U CN 219107328U CN 202223570416 U CN202223570416 U CN 202223570416U CN 219107328 U CN219107328 U CN 219107328U
- Authority
- CN
- China
- Prior art keywords
- transformer
- magnetizing
- resistor
- contactor
- start circuit
- 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.)
- Active
Links
Images
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Rectifiers (AREA)
Abstract
The utility model discloses a slow-start circuit and a device of a transformer, which are connected with the transformer, wherein the slow-start circuit of the transformer comprises: the device comprises a contactor and at least one pre-magnetizing resistor, wherein a normally open switch of the contactor is connected with each pre-magnetizing resistor in parallel, each pre-magnetizing resistor is respectively connected between each power line interface of the transformer and each input end of the mains supply, and a control end of the contactor is connected at the joint of one pre-magnetizing resistor and the transformer. When mains supply is input, the transformer is connected with the mains supply through the pre-magnetizing resistor to realize pre-magnetizing, so that residual magnetism of the transformer is partially neutralized, meanwhile, the control end of the contactor is powered on through the pre-magnetizing resistor, the normally open switch of the contactor is closed in a delayed mode, the transformer is connected with the mains supply through the normally open switch of the contactor, and slow starting of the transformer is realized. Compared with the prior art, the utility model adopts fewer electric elements and simpler circuit structure, and can effectively reduce the impact on the mains supply grid when the transformer is started.
Description
Technical Field
The utility model relates to the technical field of slow start of transformers, in particular to a slow start circuit and a slow start device of a transformer.
Background
At present, almost all medium-high power (more than 20 KW) transformers used in a commercial power grid (380V (or 220V) AC 50 Hz) can generate relatively large excitation surge current due to residual magnetism when started; this nominal current (i=p/U) is generally 8 to 12 times, and in particular high-efficiency transformers (using oriented sheet cores) may reach 14 times; causing large impact to the power grid in 0.5-2 periods (t=1/f T =10-40 ms).
After the design of the transformer is finished, each parameter of the transformer is determined; large excitation currents can cause large electromagnetic disturbances, which can cause an increase in the investment of the preceding devices and affect the stability of the parallel devices; in order to reduce the magnetizing inrush current, an external device is not added, and an external input inductance (inductance is about 10%) or an input number of turns of the transformer is generally increased (the number of turns is increased while efficiency is considered, and the corresponding wire diameter is thickened and the volume is increased).
For the first scheme, as shown in fig. 1, the series inductance mode increases the structural inductance device and the heat dissipation consideration, so that the excitation surge current is difficult to de-rate. Transformers (autotransformers are slightly smaller in size) already occupy a relatively large space, and the series inductance mode not only causes an increase in the volume of the equipment, but also increases in mass due to the increase in inductance. In addition, the introduction of the inductor cannot eliminate the excitation surge current, but only has the effect of series voltage division, the rated current of the inductor is equal to the rated current of the transformer, and the inductance is about 10% of the equivalent impedance under the rated voltage.
For the second solution, as shown in fig. 2, the number of turns or the secondary core is increased, and the structural size and weight of the solution are increased, so as to modify the design of the transformer. The transformer (the size of the autotransformer is smaller) occupies a relatively large space, the volume of the equipment is increased by increasing the number of turns or the auxiliary iron core, the weight is increased, and the heat dissipation consideration of the inductor is increased. In addition, the increase of the number of turns cannot eliminate excitation surge current, but only plays a role in excitation dispersion; the number of turns is generally increased by about 10%, and the size of the iron core, the number of secondary turns and the wire diameter are all increased.
Disclosure of Invention
The utility model mainly aims to provide a slow starting circuit and a slow starting device of a transformer, which aim to effectively reduce impact on a mains supply grid when the transformer is started by adopting fewer electric elements and a simpler circuit structure.
In order to achieve the above object, the present utility model provides a slow start circuit of a transformer, which is connected with a transformer, the slow start circuit of the transformer includes: the device comprises a contactor and at least one pre-magnetizing resistor, wherein a normally open switch of the contactor is connected with each pre-magnetizing resistor in parallel, each pre-magnetizing resistor is respectively connected between each power line interface of the transformer and each input end of mains supply, and a control end of the contactor is connected at the connection part of one pre-magnetizing resistor and the transformer.
In one embodiment, the slow start circuit of the transformer further comprises a protection circuit, wherein the protection circuit and the control end of the contactor are connected in series between two power line interfaces of the transformer and connected with one pre-magnetizing resistor.
In one embodiment, each of the pre-magnetizing resistors is subjected to a momentary maximum current of 3-5 times the transformer no-load current.
In one embodiment, the protection circuit includes a fuse or a resistor.
In one embodiment, the fuse or the resistor has a value of 2 to 3 times the rated current of the contactor.
In one embodiment, the time difference between the energization of the respective input terminals of the mains supply to the engagement of the contactor is 200ms.
In one embodiment, the transformer is a single-phase transformer or a three-phase transformer.
In one embodiment, the transformer is a single-phase transformer, the transformer slow-start circuit comprises a first contactor, a first pre-magnetizing resistor and a protection circuit, wherein,
the first end of the protection circuit is connected with the live wire input end of the mains supply and the first power line interface of the transformer, the second end of the protection circuit is connected with the first end of the control end of the first contactor, the second end of the control end of the first contactor is connected with one end of the normally open switch of the first contactor, the second end of the first pre-magnetizing resistor and the second power line interface of the transformer, and the first end of the first pre-magnetizing resistor is connected with the other end of the normally open switch of the first contactor and the zero line input end of the mains supply.
In one embodiment, the transformer is a three-phase transformer, and the transformer slow-start circuit comprises a first pre-magnetizing resistor, a second pre-magnetizing resistor, a third pre-magnetizing resistor, a second contactor and a protection circuit, wherein a first end of the first pre-magnetizing resistor is connected with a first live wire input end of the mains supply, and a second end of the first pre-magnetizing resistor is connected with a first power line interface of the transformer; the first end of the second pre-magnetizing resistor is connected with the second live wire input end of the commercial power, and the second end of the second pre-magnetizing resistor is connected with the second power line interface of the transformer; the first end of the third pre-magnetizing resistor is connected with a third live wire input end of the commercial power, and the second end of the third pre-magnetizing resistor is connected with a third power line interface of the transformer; the first pre-magnetizing resistor is connected in parallel with a first normally-open switch of the second contactor, the second pre-magnetizing resistor is connected in parallel with a second normally-open switch of the second contactor, and the third pre-magnetizing resistor is connected in parallel with a third normally-open switch of the second contactor; the control end of the second contactor and the protection circuit are connected in series and then connected between the second ends of any two pre-magnetizing resistors.
The utility model also provides a transformer slow-start device which comprises the transformer slow-start circuit.
The slow start circuit and the slow start device of the transformer have the beneficial effects that:
1. the control part of the utility model has less complex detection calculation control links, low cost, simplicity, reliability and easy implementation; the contactor control terminal directly takes electricity to the resistor back end, and the delay of the first contactor closing needs about 10 cycles (50 Hz, T=1/f, t=10T=200ms) to be closed;
2. because the dissipation power of each device of the slow start circuit is smaller, the delay is shorter (200 ms), and a heat dissipation device does not need to be particularly added;
3. the magnetizing inrush current of the transformer for the commercial power (380V (or 220V) AC 50 Hz) is controlled below 4 times rated current (the actual measured rated current is not more than 3 times) after the magnetizing inrush current is extended to about 10 cycles from 8 to 12 (even 14) times rated current in 0.5 to 2 cycles.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a prior art method for reducing the magnetizing inrush current using a series inductance approach;
FIG. 2 is a schematic diagram of the prior art for reducing the magnetizing inrush current by increasing the number of turns of the transformer or the secondary core;
FIG. 3 is a schematic diagram of a slow start circuit of a transformer according to an embodiment of the utility model;
FIG. 4 is another schematic diagram of the transformer slow start circuit shown in FIG. 3;
FIG. 5 is another schematic diagram of the transformer slow start circuit shown in FIG. 4;
FIG. 6 is another schematic diagram of the transformer slow start circuit shown in FIG. 4;
FIG. 7 is another schematic diagram of the transformer slow start circuit shown in FIG. 4;
fig. 8 is another schematic diagram of the transformer slow start circuit shown in fig. 4.
The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.
In order to avoid the situation that the direct no-load starting of the transformer TX causes larger exciting current to impact the power grid, please refer to fig. 3, the utility model proposes a slow-start circuit of the transformer, which is connected with the transformer TX, and a preferred embodiment of the slow-start circuit of the transformer comprises a contactor JK and at least one pre-magnetizing resistor R, wherein a normally open switch K of the contactor JK is connected in parallel with each pre-magnetizing resistor R, each pre-magnetizing resistor R is connected between each power line interface of the transformer TX and each input end of the mains supply, and a control end X of the contactor JK is connected at a connection point of one pre-magnetizing resistor R and the transformer TX.
It can be understood that the transformer TX in this embodiment is a medium-high power (more than 20 KW) transformer; in other embodiments, the method can also be applied to a low-power (below 20 KW) transformer according to actual conditions.
It is understood that the control terminal X of the contactor JK may be a contactor coil, and the normally open switch K of the contactor JK is closed when the control terminal X of the contactor JK is powered. The contactor JK can adopt a delay contactor, when the control end X of the contactor JK is powered on, the normally open switch K of the contactor JK is closed in a delay manner, and the specific delay time can select the delay contactor of the corresponding type according to the slow start duration of the transformer TX.
It is understood that the transformer TX may be selected as a single-phase transformer or a three-phase transformer. The number of pre-magnetizing resistors R is associated with the number of phases of the transformer TX or the grid input, for example, when the transformer TX is a single-phase transformer, the grid input is single-phase alternating current, and the number of pre-magnetizing resistors R is selected to be 1; when the transformer TX is a three-phase transformer, the grid input is a three-phase alternating current, and the number of pre-magnetizing resistors R may be selected to be 3.
It will be appreciated that each of the pre-magnetizing resistors R is subjected to a momentary maximum current of 3-5 times the transformer TX no-load current. In practical application, each pre-magnetizing resistor R may be selected according to the actual no-load current of the transformer TX, so as to configure each pre-magnetizing resistor R that is most suitable.
Optionally, referring to fig. 4, the slow start circuit of the transformer of the present utility model further includes a protection circuit 10, wherein the protection circuit 10 and the control terminal X of the contactor JK are connected in series between the two power line interfaces of the transformer TX and connected to a pre-magnetizing resistor R.
It will be appreciated that the protection circuit 10 is used to protect the contactor JK from overvoltage or overcurrent damage.
Optionally, referring to fig. 5 and 6, the protection circuit 10 may optionally include a fuse F1 or a resistor R4, where the fuse F1 or the resistor R4 is connected in series to a loop where the control terminal X of the contactor JK is located, and is connected in series with the control terminal X of the contactor JK.
Optionally, the current value of the fuse F1 or the resistor R4 is 2 to 3 times of the rated current of the contactor JK, so that the protection of the contactor JK is ensured and the overcurrent damage of the contactor JK is avoided on the premise that the fuse or the resistor does not obstruct the normal operation of the contactor JK.
When mains supply is input, the transformer TX is connected with the mains supply through the pre-magnetizing resistor R to realize pre-magnetizing, so that residual magnetism of the transformer TX is partially neutralized, meanwhile, the control end X of the contactor JK is powered on through the pre-magnetizing resistor R, the normally open switch K of the contactor JK is closed in a delayed mode, the transformer TX is connected with the mains supply through the normally open switch K of the contactor JK, and slow starting of the transformer TX is realized.
As an implementation, referring to fig. 7, in this embodiment, the transformer TX is a single-phase transformer TX1, and the slow start circuit of the transformer includes a first contactor JK1, a first pre-magnetizing resistor R1, and a protection circuit 10. The protection circuit 10 may optionally include a fuse F1 or a resistor.
It can be understood that the first contactor JK1 in the present embodiment is an expression form of the above-mentioned contactor JK, the first pre-magnetizing resistor R1 is the above-mentioned pre-magnetizing resistor R, and the protection circuit 10 is the above-mentioned protection circuit 10, which is not described herein.
The first end of the protection circuit 10 is connected to the live wire input end L of the mains supply and the first power line interface of the single-phase transformer TX1, the second end of the protection circuit 10 is connected to the first end of the control end X1 of the first contactor JK1, the second end of the control end X1 of the first contactor JK1 is connected to one end of the first normally open switch K1 of the first contactor JK1, the second end of the first pre-magnetizing resistor R1 and the second power line interface of the single-phase transformer TX1, and the first end of the first pre-magnetizing resistor R1 is connected to the other end of the first normally open switch K1 of the first contactor JK1 and the neutral line input end N of the mains supply.
In this embodiment, the protection circuit 10 includes a fuse F1, and the value of the fuse F1 may be 2 to 3 times the rated current of the first contactor JK 1.
In this embodiment, when the single-phase transformer TX1 is pre-magnetized by the first pre-magnetizing resistor R1 and runs in no-load, the terminal voltage divided by the control terminal X1 of the first contactor JK1 is not less than 75% of the rated value thereof; the time difference between the power supply and the first contactor JK1 is 200ms.
It will be appreciated that this embodiment is used with a single phase ac power grid having a utility power grid of 50hz 220 (230 or 240) VAC, i.e. a single phase ac power with a current of 50hz 220 (230 or 240) VAC input to the live wire input L and the neutral wire input N of the utility power.
It can be appreciated that in fig. 7, the idle current of the single-phase transformer TX1 is io=ao, and the rated current is i=p/U. Therefore, the efficiency of the transformer with more than medium power (more than 20 KW) is generally more than 95 percent, and the design is optimized by P Copper loss ＝P Iron loss of ，P Iron loss of <P Copper loss +P Iron loss of ≤5％，P Iron loss of <5% P, no-load current Io < 5% I.
In this scheme, the first pre-magnetizing resistor R1 receives no-load current of the single-phase transformer TX1 with the instantaneous maximum current value of 3-5, 3*5% -I-5*5% -I, i.e. the extreme value when the default transformer input end (the control end X1 of the first contactor JK 1) is short-circuited;
R1＝U/IR1＝220/(3*5％*I)～220/(3*5％*I)。
when the transformer TX1 is pre-magnetized and runs in a null mode through the first pre-magnetizing resistor R1, the terminal voltage of the control terminal X1 of the first contactor JK1 is not less than 75% of the rated value. The value of the fuse F1 can be 2 to 3 times of the rated current of the first contactor JK1, and the fuse F1 is used for protecting the first contactor JK1 so as to reach the voltage for normal starting, so that the slow starting device is started normally; this time difference (the mains supply is connected to the first contactor JK1 to suck for about 200 ms) pre-magnetizes the single-phase transformer TX1, the remanence is partially neutralized, and after the first contactor JK1 is sucked, the value of the magnetizing inrush current is smaller than 4 times of the rated value.
As another embodiment, referring to fig. 8, in the present embodiment, the transformer TX is a three-phase transformer TX2, and the slow start circuit of the transformer includes a first pre-magnetizing resistor R1, a second pre-magnetizing resistor R2, a third pre-magnetizing resistor R3, a second contactor JK2, and a protection circuit 10. Likewise, the protection circuit 10 may optionally include a fuse F1 or a resistor R4.
It can be understood that the second contactor JK2 in the present embodiment is a representation of the above-mentioned contactor JK, the first pre-magnetizing resistor R1, the second pre-magnetizing resistor R2, and the third pre-magnetizing resistor R3 are the above-mentioned pre-magnetizing resistors, and the protection circuit 10 is the above-mentioned protection circuit 10, which is not described herein.
The first end of the first pre-magnetizing resistor R1 is connected with a first live wire input end L1 of the commercial power, and the second end of the first pre-magnetizing resistor R2 is connected with a first power line interface of the three-phase transformer TX 2; the first end of the second pre-magnetizing resistor R2 is connected with the second live wire input end L2 of the commercial power, and the second end of the second pre-magnetizing resistor R2 is connected with the second power line interface of the three-phase transformer TX 2; the first end of the third pre-magnetizing resistor R3 is connected with a third live wire input end L3 of the commercial power, and the second end of the third pre-magnetizing resistor R3 is connected with a third power line interface of the three-phase transformer TX 2; the first pre-magnetizing resistor R1 is connected with the first normally-open switch K1 of the second contactor JK2 in parallel, the second pre-magnetizing resistor R2 is connected with the second normally-open switch K2 of the second contactor JK2 in parallel, and the third pre-magnetizing resistor R3 is connected with the third normally-open switch K3 of the second contactor JK2 in parallel; the control end of the second contactor JK2 and the protection circuit 10 are connected in series and then connected between the second ends of any two pre-magnetizing resistors.
In this embodiment, the protection circuit 10 includes the fuse F1, and the value of the fuse F1 may be 2 to 3 times the rated current of the second contactor JK 2.
When the three-phase transformer TX2 is pre-magnetized through the first pre-magnetizing resistor R1 and runs in a no-load mode, the terminal voltage divided by the control terminal of the second contactor JK2 is not less than 75% of the rated value of the terminal voltage; and the time difference from the access of the commercial power to the suction of the contactor is 200ms.
It will be appreciated that the present embodiment is used in a three-phase ac power network with a mains power grid of 50hz 380 (400 or 415) VAC, i.e. a three-phase ac power with a current of 50hz 380 (400 or 415) VAC input by the first line input L1, the second line input L2 and the third line input L3 of the mains power.
It can be understood that in fig. 8, the no-load current of the three-phase transformer TX2 is io=ao, and the rated current is i=p/U. Therefore, the efficiency of the transformer with more than medium power (more than 30 KW) is generally more than 95 percent, and the design is optimized by P Copper loss ＝P Iron loss of ，P Iron loss of <P Copper loss +P Iron loss of ≤5％，P Iron loss of <5% P, no-load current Io < 5% I. In this scheme, the first pre-magnetizing resistor R1, the second pre-magnetizing resistor R2, and the third pre-magnetizing resistor R3 bear no-load current of the transformer with the instantaneous maximum current value of 3-5, 3*5% -i.e. 5*5% -I, i.e. the extreme value when the input end (control end of the contactor) of the default transformer is short-circuited;
R1＝R2＝R3＝U/IR1＝220/(3*5％*I.)～220/(3*5％*I)。
when the three-phase transformer TX2 is pre-magnetized and runs in a null mode through the first pre-magnetizing resistor R1, the second pre-magnetizing resistor R2 and the third pre-magnetizing resistor R3, the terminal voltage of the control terminal of the second contactor JK2 is not less than 75% of the rated value of the control terminal. The value of the fuse F1 can be 2-3 times of the rated current of the second contactor JK2, and the fuse F1 is used for protecting the second contactor JK2 so as to reach the voltage for normal starting, so that the slow starting device is started normally; this time difference (about 200ms is drawn from the mains supply to the second contactor JK 2) pre-magnetizes the three-phase transformer TX2, the remanence is partially neutralized, and after the second contactor JK2 is drawn, the value of the magnetizing inrush current is less than 4 times of the rated value.
It should be noted that, the current at the control end of the second contactor JK2 is far smaller than the no-load current of the three-phase transformer TX2, and this scheme is not calculated.
The embodiment also provides a transformer slow-start device, which comprises the transformer slow-start circuit.
In summary, the transformer slow start circuit and the device according to the embodiment have the following beneficial effects:
1. the control part of the embodiment has less complicated detection calculation control links, low cost, simplicity, reliability and easy implementation; the control end X (also the control end X1 and the control end X2) of the contactor JK (also the first contactor JK1 and the first contactor JK 2) is directly electrified at the rear end of the pre-magnetizing resistor R (also the first pre-magnetizing resistor R1, the second pre-magnetizing resistor R2 and the third pre-magnetizing resistor R3), and the delay contactor JK (also the first contactor JK1 and the first contactor JK 2) is closed for about 10 periods (50 Hz, T=1/f, t=10T=200ms);
2. because the dissipation power of each device of the slow start circuit is smaller, the delay is shorter (200 ms), and a heat dissipation device does not need to be particularly added;
3. the magnetizing inrush current of a transformer TX (comprising a single-phase transformer TX1 and a three-phase transformer TX 2) for commercial power (380V (or 220V) AC 50 Hz) is extended from 8-12 (even 14) times of rated current in 0.5-2 periods to about 10 periods, and then the magnetizing inrush current is correspondingly and effectively controlled below 4 times of rated current (the rated current which is actually measured to be not more than 3 times).
The foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structural changes made by the specification and drawings of the present utility model or direct/indirect application in other related technical fields are included in the scope of the present utility model.
Claims (10)
1. A transformer slow start circuit, characterized in that is connected with the transformer, the transformer slow start circuit includes: the device comprises a contactor and at least one pre-magnetizing resistor, wherein a normally open switch of the contactor is connected with each pre-magnetizing resistor in parallel, each pre-magnetizing resistor is respectively connected between each power line interface of the transformer and each input end of mains supply, and a control end of the contactor is connected at the connection part of one pre-magnetizing resistor and the transformer.
2. The slow start circuit of claim 1, further comprising a protection circuit connected in series with the control end of the contactor between the two power line interfaces of the transformer and connected to one of the pre-magnetizing resistors.
3. The transformer slow start circuit of claim 2, wherein each of the pre-magnetizing resistors is subjected to a momentary maximum current of 3-5 times the transformer no-load current.
4. The transformer slow start circuit of claim 2, wherein the protection circuit comprises a fuse or a resistor.
5. The transformer slow start circuit of claim 4, wherein the fuse or the resistor has a value of 2 to 3 times the rated current of the contactor.
6. The slow start circuit of claim 2, wherein the time difference between the supply of each input terminal and the engagement of the contactor is 200ms.
7. The slow start circuit of any one of claims 2 to 6, wherein the transformer is a single-phase transformer or a three-phase transformer.
8. The transformer slow start circuit of claim 7, wherein the transformer is a single-phase transformer, the transformer slow start circuit comprises a first contactor, a first pre-magnetizing resistor, and a protection circuit, wherein,
the first end of the protection circuit is connected with the live wire input end of the mains supply and the first power line interface of the transformer, the second end of the protection circuit is connected with the first end of the control end of the first contactor, the second end of the control end of the first contactor is connected with one end of the normally open switch of the first contactor, the second end of the first pre-magnetizing resistor and the second power line interface of the transformer, and the first end of the first pre-magnetizing resistor is connected with the other end of the normally open switch of the first contactor and the zero line input end of the mains supply.
9. The transformer slow-start circuit of claim 7, wherein the transformer is a three-phase transformer, the transformer slow-start circuit comprises a first pre-magnetizing resistor, a second pre-magnetizing resistor, a third pre-magnetizing resistor, a second contactor and a protection circuit, wherein a first end of the first pre-magnetizing resistor is connected with a first live wire input end of the mains supply, and a second end of the first pre-magnetizing resistor is connected with a first power line interface of the transformer; the first end of the second pre-magnetizing resistor is connected with the second live wire input end of the commercial power, and the second end of the second pre-magnetizing resistor is connected with the second power line interface of the transformer; the first end of the third pre-magnetizing resistor is connected with a third live wire input end of the commercial power, and the second end of the third pre-magnetizing resistor is connected with a third power line interface of the transformer; the first pre-magnetizing resistor is connected in parallel with a first normally-open switch of the second contactor, the second pre-magnetizing resistor is connected in parallel with a second normally-open switch of the second contactor, and the third pre-magnetizing resistor is connected in parallel with a third normally-open switch of the second contactor; the control end of the second contactor and the protection circuit are connected in series and then connected between the second ends of any two pre-magnetizing resistors.
10. A transformer slow start device comprising a transformer slow start circuit as claimed in any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223570416.6U CN219107328U (en) | 2022-12-30 | 2022-12-30 | Transformer slow start circuit and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223570416.6U CN219107328U (en) | 2022-12-30 | 2022-12-30 | Transformer slow start circuit and device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219107328U true CN219107328U (en) | 2023-05-30 |
Family
ID=86455031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223570416.6U Active CN219107328U (en) | 2022-12-30 | 2022-12-30 | Transformer slow start circuit and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219107328U (en) |
-
2022
- 2022-12-30 CN CN202223570416.6U patent/CN219107328U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tseng et al. | Voltage compensation-type inrush current limiter for reducing power transformer inrush current | |
| CN111865177A (en) | Power supply system for supplying power to frequency converter, frequency conversion system and pre-magnetizing method | |
| CN114204532A (en) | Distribution circuit for reducing starting impact current of transformer in radar system | |
| CN219107328U (en) | Transformer slow start circuit and device | |
| CN105356545A (en) | Power supply device for electric safety acquisition module | |
| CN214410949U (en) | Phase-shifting transformer, voltage conversion system and frequency conversion system | |
| JP3180300U (en) | Single-phase reactor power saving device | |
| CN109742742A (en) | A kind of excitation surge current inhibition system and method based on nonlinear resistive element | |
| CN204947951U (en) | A kind of generator linear resistance and nonlinear resistance mixing demagnetization circuit | |
| CN112865180B (en) | Flexible grid-connected auxiliary device of power transformer | |
| CN205092766U (en) | Charging system in advance suitable for super large power high voltage transformers | |
| Rachman et al. | Inrush Current Limiter in 3-Phase Transformer Using AC Voltage Controller Simulation Using SIMULINK® | |
| CN204794015U (en) | Electric leakage circuit breaker | |
| CN204732846U (en) | The under-voltage release of mold cased circuit breaker | |
| CN219351276U (en) | Starting current suppression device for high-capacity series resonance voltage-withstanding equipment | |
| CN219372010U (en) | Device for avoiding closing inrush current of low-voltage isolation transformer and low-voltage power supply system | |
| CN218677007U (en) | Closing control loop of alternating current filter circuit breaker | |
| CN216623972U (en) | Pre-magnetizing device for power supply transformer | |
| CN218648746U (en) | Light-load electricity saver for alternating current motor | |
| CN109448952A (en) | A kind of low pressure pre-magnetizing system and method for high-power fairing | |
| CN216851317U (en) | Multifunctional self-checking closing power supply device | |
| CN113824121B (en) | Structure applied to flexible direct-current comprehensive voltage regulating device for inhibiting common-mode interference | |
| CN217361344U (en) | Anti-interference large current generating device | |
| CN219372020U (en) | Surge suppression circuit | |
| CN205789445U (en) | A kind of adjustable miniature transformer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |