CN215817504U - Motor soft start circuit and motor start cabinet - Google Patents
Motor soft start circuit and motor start cabinet Download PDFInfo
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- CN215817504U CN215817504U CN202121473060.7U CN202121473060U CN215817504U CN 215817504 U CN215817504 U CN 215817504U CN 202121473060 U CN202121473060 U CN 202121473060U CN 215817504 U CN215817504 U CN 215817504U
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Abstract
The utility model relates to the technical field of motor starting, and provides a motor soft starting circuit and a motor starting cabinet. The motor soft start circuit comprises a soft starter, a motor protector, an intermediate relay KA1 and a main breaker; the motor is connected with a three-phase power supply through a soft starter, and a normally open contact of the main breaker is arranged on a power supply circuit of the motor; the detection voltage input end of the motor protector is connected with the power supply line and used for detecting the three-phase voltage of the power supply line, the coil of the intermediate relay KA1 is connected in series with the fault output end of the motor protector, and the coil of the main circuit breaker and the normally open contact of the intermediate relay KA1 are connected in series between any phase power supply and the ground wire. The motor soft start circuit can output faults through the motor protector under the conditions that two-phase silicon controlled rectifiers are broken down and faults are not reported after the soft starter is started, so that a power supply circuit of the motor is powered off, and the motor is protected.
Description
Technical Field
The utility model relates to the technical field of motor starting, in particular to a motor soft starting circuit and a motor starting cabinet.
Background
High power motors are typically started and protected using a soft starter. However, due to the quality, service life and other problems of the soft starter, the soft starter does not report a fault in a fault state, and even two-phase breakdown of the silicon controlled rectifier of the soft starter occurs, so that a two-phase power supply is supplied to the motor in a shutdown state. The motor is equivalent to the motor which is still in phase-loss operation in a shutdown state, so that the motor generates winding breakdown and burnout in a short few minutes, the interruption of safe operation and production is influenced, the maintenance cost of the high-power motor is increased, and the cost is increased by replacing the soft starter with higher reliability.
SUMMERY OF THE UTILITY MODEL
The utility model provides a motor soft start circuit and a motor start cabinet, which are used for solving the problems that a soft starter adopted in the existing high-power motor start technology does not report faults in a fault state, so that a motor runs in a phase failure mode to cause motor winding breakdown and burnout.
The utility model provides a motor soft start circuit, which comprises a soft starter, a motor protector, an intermediate relay KA1 and a main circuit breaker, wherein the soft starter is arranged on the motor protector; the motor is connected with a three-phase power supply through the soft starter, and a normally open contact of the main breaker is arranged on a power supply circuit of the motor; the detection voltage input end of the motor protector is connected with the power supply line and used for detecting the three-phase voltage of the power supply line, the coil of the intermediate relay KA1 is connected in series with the fault output end of the motor protector, and the coil of the main circuit breaker and the normally open contact of the intermediate relay KA1 are connected between any phase power supply and the ground wire in series.
The soft start circuit of the motor further comprises a secondary control circuit, wherein the secondary control circuit is connected between any phase power supply of the three-phase power supply and a ground wire and is used for controlling the soft starter to start.
According to the soft start circuit of the motor, two ends of the soft starter are connected with a normal operation circuit in parallel, a normally open contact of a main contactor KM is arranged on the normal operation circuit, the secondary control circuit comprises a first branch circuit, a bypass contact of the soft starter and the contactor KM are connected in series on the first branch circuit, and the normally open contact of the main contactor KM is connected in parallel at two ends of the soft starter.
According to the soft start circuit of the motor, the secondary control circuit further comprises a second branch, the second branch is connected with the first branch in parallel, a start button and a coil of an intermediate relay KA2 are sequentially connected to the second branch in series, two ends of the start button are connected with a first normally open contact of the intermediate relay KA2 in parallel, and a start end of the soft starter is connected with a second normally open contact of the intermediate relay KA 2.
According to the soft starting circuit of the motor, the second branch is also provided with the normally closed contact of the intermediate relay KA1, and the normally closed contact of the intermediate relay KA1 is connected with the starting button and the coil of the intermediate relay KA2 in series.
The soft start circuit of the motor further comprises a stop button, wherein the stop button is arranged on the second branch and used for cutting off the second branch.
According to the soft start circuit of the motor, the secondary control circuit further comprises a third branch circuit, and a normally open contact and a fault indicator lamp of a fault output end of the motor protector are connected in series on the third branch circuit.
According to the motor soft start circuit provided by the utility model, the power end of the soft starter and the power end of the motor protector are respectively connected with any phase power supply of the three-phase power supply through the circuit breaker.
The soft start circuit of the motor further comprises a current transformer, wherein a current input end of the current transformer is connected with the power supply line, and a current output end of the current transformer is connected with a current detection input end of the motor protector.
The utility model also provides a motor starting cabinet which comprises a cabinet body and any one of the motor soft starting circuits arranged in the cabinet body.
According to the motor soft start circuit and the motor start cabinet provided by the utility model, the current of the power supply line of the motor is detected through the motor protector. After the soft starter is started, if two-phase silicon controlled breakdown occurs and the motor runs in a phase-lacking mode in a shutdown state, the motor protector outputs a fault according to the collected abnormal three-phase voltage of the motor power supply line, so that the normally open contact of the intermediate relay KA1 is closed, the contact of the main circuit breaker QF in a closed state is disconnected, the power supply line of the motor is powered off, and the motor is protected.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a soft start circuit of a motor according to the present invention;
fig. 2 is a schematic structural diagram of a secondary control circuit of the motor soft start circuit provided by the utility model.
Reference numerals:
1. a soft starter; 2. a motor protector; 3. and a secondary control circuit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the embodiments of the present invention, it should be noted that the terms "first", "second" and "third" are used for the sake of clarity in describing the numbering of the components of the product and do not represent any substantial difference, unless explicitly stated or limited otherwise. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.
The motor soft start circuit of the present invention is described below in conjunction with fig. 1-2.
Fig. 1 is a schematic structural diagram of a soft start circuit of a motor according to the present invention. The motor soft start circuit provided by the embodiment of the utility model comprises a soft starter 1, a motor protector 2, an intermediate relay KA1 and a main breaker QF. The motor is connected to a three-phase power supply through a soft starter 1, and contacts of a main breaker QF are provided on a power supply line of the motor. And the detection voltage input end of the motor protector 2 is connected with the power supply line and used for detecting the three-phase voltage of the power supply line. The coil of the intermediate relay KA1 is connected in series with the fault output end GZ of the motor protector 2, and the coil of the main breaker QF and the normally open contact of the intermediate relay KA1 are connected in series between any phase power supply and the ground wire N.
The three-phase power supply comprises an L1 phase power supply, an L2 phase power supply and an L3 phase power supply, and the motor is connected with the L1 phase power supply, the L2 phase power supply and the L3 phase power supply through power supply lines. The power supply line is provided with contacts of a main breaker QF for controlling the closing or opening thereof by a coil of the main breaker QF to connect or disconnect the motor with or from the three-phase power supply. The power supply end of the soft starter 1 is connected with any phase power supply through a breaker QF1, the power supply end of the motor protector 2 is connected with any phase power supply through a breaker QF2, and the grounding end of the motor protector 2 is connected with a ground wire.
And two ends of the soft controller SS are connected with a normal operation circuit in parallel, and after the soft start of the motor is finished, the three-phase power supply directly supplies power to the motor through the normal operation circuit. And a normally-open contact of the main contactor KM is arranged on the normal operation circuit and used for conducting or cutting off the connection between the motor and the three-phase power supply.
The motor is firstly soft-started by the soft starter 1 and then enters normal operation. In the normal operation process of the motor, the contact of the main breaker QF and the normally open contact of the main contactor KM are both in a closed state. If two-phase thyristor breakdown occurs after the soft starter 1 is started. After the motor is manually shut down or the motor is in fault shutdown, two-phase current is still input into the motor through the soft starter 1, so that the motor runs in a phase-lacking mode. At this time, the three-phase voltage detected by the motor protector 2 is abnormal, the soft starter 1 is judged to have a fault of breakdown of two-phase silicon controlled rectifiers, and current is output through a fault output point, so that the coil of the intermediate relay KA1 is electrified, the normally open contact of the intermediate relay KA1 is closed, the coil of the main circuit breaker QF is electrified, and the contact of the main circuit breaker QF is disconnected.
The utility model provides a motor soft start circuit, which detects the current of a power supply line of a motor through a motor protector 2. After the soft starter is started, if two-phase silicon controlled breakdown occurs and the motor runs in a phase-lacking mode in a shutdown state, the motor protector 2 enables a normally open contact of the intermediate relay KA1 to be closed according to the collected abnormal three-phase voltage output faults of the motor power supply line, the contact of the main circuit breaker QF in a closed state is disconnected, the power supply line of the motor is lost, and therefore the motor is protected.
Further, the soft start circuit of the motor provided by the embodiment of the utility model further comprises a current transformer, wherein a current input end of the current transformer is connected with a power supply line, and a current output end of the current transformer is connected with a detection current input end of the motor protector 2. The current transformer may be a three-phase feedthrough current transformer. The motor protector 2 collects current on a power supply line of the motor through a current transformer, judges whether faults such as overcurrent, blockage, quick break, overlong starting time, unbalanced three-phase current and the like exist in a main loop according to the collected current value, and can output fault signals through a fault output end.
The soft start circuit of the motor provided by the embodiment of the utility model further comprises a secondary control circuit 3, wherein the secondary control circuit 3 is connected between any phase power supply of the three-phase power supply and the ground wire and is used for controlling the soft starter to start. Fig. 2 is a schematic structural diagram of a secondary control circuit of the motor soft start circuit provided by the present invention. In this embodiment, one end of the secondary control circuit 3 is connected to the L1 phase power supply, and the other end is connected to the ground.
Wherein, both ends of soft starter 1 are connected with normal operating circuit in parallel, are provided with the normally open contact of main contactor KM on the normal operating circuit. The secondary control circuit 3 comprises a first branch, and a bypass contact of the soft starter and the contactor KM are connected in series on the first branch. And the two ends of the soft starter are connected in parallel with a normally open contact of the main contactor KM and used for switching on or off the connection between a three-phase power supply and the motor. After the soft starter 1 receives the starting signal and finishes starting, the soft starter bypass end PL outputs to close the ground bypass contact on the first branch, so that the coil of the main contactor KM is electrified and is communicated with a normal operation circuit, and the motor operates normally.
In the embodiment of the present invention, the secondary control circuit 3 further includes a second branch, and the second branch is connected in parallel with the first branch. The second branch is connected with a start button SB2 and a coil of an intermediate relay KA2 in sequence in series. The two ends of the starting button SB2 are connected in parallel with a first normally open contact of the intermediate relay KA2, and the starting end of the soft starter 1 is connected with a second normally open contact of the intermediate relay KA 2. When the motor is started, the start button SB2 is pressed and the second branch is conducted. The coil of the intermediate relay KA2 is electrified, and the first normally open contact of the intermediate relay KA2 is closed to realize self-locking. And the second normally open contact of the intermediate relay KA2 is closed, and the soft starter 1 receives the starting signal, and the soft starter 1 starts to soft start the motor.
Furthermore, the second branch is also provided with a normally closed contact of an intermediate relay KA1, and the normally closed contact of the intermediate relay KA1 is connected with the starting button SB2 and a coil of the intermediate relay KA2 in series. When the soft starter 1 is subjected to controllable breakdown of two-phase silicon, when the fault point of the motor protector 2 is output, the coil of the intermediate relay KA1 is electrified, the normally closed contact of the intermediate relay KA1 on the second branch is disconnected, the coil of the intermediate relay KA2 is electrified, and the second normally open contact of the intermediate relay KA2 is recovered to be disconnected, so that the soft starter 1 is tripped. The soft starter 1 cannot receive a starting signal, so that a bypass contact on the first branch is disconnected, a coil of the main contactor KM loses power, and a normally open contact of the main contactor KM is disconnected.
Meanwhile, a normally open contact of the intermediate relay KA1 is closed, a coil of the main breaker QF is electrified, a contact of the main breaker QF in a closed state is disconnected, a power supply circuit of the motor is powered off, and the situation that when the soft starter 1 has a two-phase silicon controllable breakdown fault, a motor winding is broken down and burnt out is avoided. By providing the first branch and the second branch, when the coil of the intermediate relay KA1 is energized, the connection between the motor and the soft starter 1 and the power supply can be simultaneously cut off.
The soft start circuit of the motor provided by the embodiment of the utility model further comprises a stop button SB1, and the stop button SB1 is arranged on the second branch and used for cutting off the second branch. Specifically, the stop button SB1 is connected in series with the normally closed contact of the intermediate relay KA1, the start button SB2, and the coil of the intermediate relay KA2 for manually cutting off the second branch, thereby closing the soft starter 1. After the soft starter 1 is closed, the bypass contact of the soft starter is disconnected, the coil of the main contactor KM is powered off, and the normally open contact of the main contactor KM is disconnected. In case the softstarter does not fail, the motor may be shut down.
In the embodiment of the utility model, the secondary control circuit 3 further comprises a third branch, and a normally open contact of the fault output end GZ of the motor protector 2 and a fault indicator YE are connected in series on the third branch. When the fault point of the motor protector 2 is output, the normally open contact of the fault output end GZ of the motor protector 2 is closed, and the fault indicator lamp is lightened to prompt that the condition of the motor running in the open phase exists.
Meanwhile, a coil of the intermediate relay KA1 is electrified, a normally open contact of the intermediate relay KA1 is closed, a coil of the main circuit breaker QF is electrified, a contact of the main circuit breaker QF in a closed state is disconnected, and a power supply line of the motor loses electricity. The normally closed contact of the intermediate relay KA1 is disconnected, the coil of the intermediate relay KA2 loses power, the second normally open contact of the intermediate relay KA2 is disconnected, and the soft starter 1 is tripped.
In the embodiment of the utility model, the power supply end of the soft starter 1 and the power supply end of the motor protector 2 are respectively connected with any phase power supply of a three-phase power supply through a breaker. Specifically, the circuit breaker comprises a circuit breaker QF1 and a circuit breaker QF2, wherein the power supply end of the soft starter 1 is connected with a power supply through the circuit breaker QF1, and the power supply end of the motor protector 2 is connected with the power supply through the circuit breaker QF 2. The soft starter 1 is powered by closing the circuit breaker QF1 and the motor protector 2 is powered by closing the circuit breaker QF 2.
In the embodiment of the utility model, the voltage detection input end of the motor protector 2 is connected with a three-phase power supply through a fuse FU1, and the secondary control circuit 3 is connected with any one phase power supply of the three-phase power supply through a fuse FU 2.
The utility model also provides a motor starting cabinet which comprises a cabinet body and the motor soft starting circuit arranged in the cabinet body.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A motor soft start circuit is characterized by comprising a soft starter, a motor protector, an intermediate relay KA1 and a main breaker; the motor is connected with a three-phase power supply through the soft starter, and a normally open contact of the main breaker is arranged on a power supply circuit of the motor; the detection voltage input end of the motor protector is connected with the power supply line and used for detecting the three-phase voltage of the power supply line, the coil of the intermediate relay KA1 is connected in series with the fault output end of the motor protector, and the coil of the main circuit breaker and the normally open contact of the intermediate relay KA1 are connected between any phase power supply and the ground wire in series.
2. The motor soft start circuit of claim 1, further comprising a secondary control circuit connected between any phase power supply of the three phase power supply and ground for controlling the soft starter to start.
3. The motor soft start circuit according to claim 2, wherein a normal operation circuit is connected in parallel to two ends of the soft starter, a normally open contact of a main contactor KM is arranged on the normal operation circuit, the secondary control circuit comprises a first branch, a bypass contact of the soft starter and the contactor KM are connected in series to the first branch, and the normally open contact of the main contactor KM is connected in parallel to two ends of the soft starter.
4. The motor soft start circuit according to claim 3, characterized in that the secondary control circuit further comprises a second branch, the second branch is connected in parallel with the first branch, a start button and a coil of an intermediate relay KA2 are sequentially connected in series on the second branch, a first normally open contact of the intermediate relay KA2 is connected in parallel with two ends of the start button, and a second normally open contact of the intermediate relay KA2 is connected with the start end of the soft starter.
5. The soft start circuit of claim 4, wherein the second branch is further provided with a normally closed contact of the intermediate relay KA1, and the normally closed contact of the intermediate relay KA1 is connected in series with the start button and the coil of the intermediate relay KA 2.
6. The motor soft start circuit of claim 4, further comprising a stop button disposed on the second branch for cutting off the second branch.
7. The soft start circuit of claim 3, wherein the secondary control circuit further comprises a third branch, and a normally open contact and a fault indicator lamp of a fault output end of the motor protector are connected in series to the third branch.
8. The motor soft start circuit of claim 1, wherein the power terminals of the soft starter and the motor protector are connected to any one phase power supply of the three phase power supply via a circuit breaker, respectively.
9. The soft start circuit of claim 1, further comprising a current transformer, wherein a current input terminal of the current transformer is connected to the power supply line, and a current output terminal of the current transformer is connected to a current detection input terminal of the motor protector.
10. A motor starting cabinet is characterized by comprising a cabinet body and a motor soft starting circuit which is arranged in the cabinet body and is as claimed in any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121473060.7U CN215817504U (en) | 2021-06-30 | 2021-06-30 | Motor soft start circuit and motor start cabinet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121473060.7U CN215817504U (en) | 2021-06-30 | 2021-06-30 | Motor soft start circuit and motor start cabinet |
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| Publication Number | Publication Date |
|---|---|
| CN215817504U true CN215817504U (en) | 2022-02-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121473060.7U Active CN215817504U (en) | 2021-06-30 | 2021-06-30 | Motor soft start circuit and motor start cabinet |
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| CN (1) | CN215817504U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115561629A (en) * | 2022-09-16 | 2023-01-03 | 中核检修有限公司 | Portable motor no-load test device |
-
2021
- 2021-06-30 CN CN202121473060.7U patent/CN215817504U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115561629A (en) * | 2022-09-16 | 2023-01-03 | 中核检修有限公司 | Portable motor no-load test device |
| CN115561629B (en) * | 2022-09-16 | 2023-09-01 | 中核检修有限公司 | Portable motor no-load test device |
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