阅读说明：本技术 一种避免二次冲击电流的发电机软启动装置 (Generator soft starting device capable of avoiding secondary impact current ) 是由 彭涛 徐祥国 于 2019-01-11 设计创作，主要内容包括：本发明涉及电机启动领域,特涉及一种避免二次冲击电流的发电机软启动装置。本发明的市三相电通过第一常开节点与电动机连接,发电机通过第二常开节点与电动机连接,检测装置设置在电动机侧,用于检测电动机的运行参数,启动控制装置与检测装置连接,启动控制装置输出信号分别与发电机控制装置、第一控制按钮和第二控制按钮连接,第一接触器线圈、第二常闭节点、第一控制按钮串联后接入控制电源,第二接触器线圈、第一常闭节点、第二控制按钮串联后接入控制电源,电源同期装置与发电机、市三相电连接,电源同期装置用于检测市三相电和发电机的电压、频率、相序是否相同。本发明解决了交流电机启动电流过大的问题,避免出现二次冲击电流。(The invention relates to the field of motor starting, in particular to a generator soft starting device capable of avoiding secondary impact current. The city three-phase power supply synchronization device is connected with a generator and a city three-phase power supply, and is used for detecting whether the voltage, the frequency and the phase sequence of the city three-phase power supply are the same or not. The invention solves the problem of large current flow when the alternating current motor is started, and avoids secondary impact current.)

1. A generator soft start device for avoiding secondary impact current comprises a detection device, a start control device, a generator control device, a city three-phase power supply, a motor, a generator, a first contactor, a second contactor, a first control button, a second control button and a power supply synchronization device; the first contactor comprises a first contactor coil, a first normally closed node and a first normally open node, and the second contactor comprises a second contactor coil, a second normally closed node and a second normally open node; the method is characterized in that: the city three-phase current is connected with the motor through a first normally open node, the generator is connected with the motor through a second normally open node, the detection device is arranged on the side of the motor and used for detecting the operation parameters of the motor, the starting control device is connected with the detection device, the output signal of the starting control device is respectively connected with the generator control device, the first control button and the second control button, the first contactor coil, the second normally closed node and the first control button are connected in series and then connected into a control power supply, the second contactor coil, the first normally closed node and the second control button are connected in series and then connected into the control power supply, the power supply synchronizing device is connected with the generator and the city three-phase current, and the power supply synchronizing device is used for detecting whether the voltage, the frequency and the phase sequence of the city three-.

2. The soft-start device of generator for avoiding secondary surge current as claimed in claim 1, wherein: the control power supply is a 24v direct current power supply, and the first contactor and the second contactor are 24v direct current contactors.

3. The soft-start device of generator for avoiding secondary surge current as claimed in claim 1, wherein: the control power supply is 220v alternating current, and the first contactor and the second contactor are 220v alternating current contactors.

4. The soft-start device of generator for avoiding secondary surge current as claimed in claim 1, wherein: a fuse is arranged between the commercial three-phase power and the first normally-open node.

5. The soft-start device of generator for avoiding secondary surge current as claimed in claim 1, wherein: a fuse is arranged between the generator and the first normally open node.

Technical Field

The invention relates to the field of motor starting, in particular to a generator soft starting device capable of avoiding secondary impact current.

Background

During starting of an ac motor, the full-voltage starting current is typically 4 to 7 times the rated current. The higher power motors can impact the grid in situations where the grid capacity is limited, and the soft start device is selected to limit the starting current. The existing soft start device reduces the start current by voltage reduction or frequency reduction, and has advantages and disadvantages respectively. When the generator power supply is converted to the mains supply for starting the motor by the generator, secondary impact current occurs, and certain impact is caused on equipment and a power grid.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a generator soft start device for avoiding secondary impact current. The invention controls the motor to start through the generator, and the motor is switched to the city three-phase power supply after the motor is normally started, thereby solving the problem of large current flow of the starting of the alternating current motor, ensuring the voltage, the frequency and the phase sequence of the city three-phase power and the generator to be the same during the conversion through the power supply synchronization device, and avoiding the occurrence of secondary rush current.

The technical scheme of the invention is as follows: a generator soft start device for avoiding secondary impact current comprises a detection device, a start control device, a generator control device, a commercial three-phase power supply, a motor, a generator, a first contactor, a second contactor, a first control button, a second control button and a power supply synchronization detection device; the first contactor comprises a first contactor coil, a first normally closed node and a first normally open node, and the second contactor comprises a second contactor coil, a second normally closed node and a second normally open node; the method is characterized in that: the city three-phase current is connected with the motor through a first normally open node, the generator is connected with the motor through a second normally open node, the detection device is arranged on the side of the motor and used for detecting the operation parameters of the motor, the starting control device is connected with the detection device, the output signal of the starting control device is respectively connected with the generator control device, the first control button and the second control button, the first contactor coil, the second normally closed node and the first control button are connected in series and then connected into a control power supply, the second contactor coil, the first normally closed node and the second control button are connected in series and then connected into the control power supply, the power supply synchronizing device is connected with the generator and the city three-phase current, and the power supply synchronizing device is used for detecting whether the voltage, the frequency and the phase sequence of the city three-.

According to the generator soft start device for avoiding secondary impact current, the device is characterized in that: the control power supply is a 24v direct current power supply, and the first contactor and the second contactor are 24v direct current contactors.

According to the generator soft start device for avoiding secondary impact current, the device is characterized in that: the control power supply is 220v alternating current, and the first contactor and the second contactor are 220v alternating current contactors.

According to the generator soft start device for avoiding secondary impact current, the device is characterized in that: a fuse is arranged between the commercial three-phase power and the first normally-open node.

According to the generator soft start device for avoiding secondary impact current, the device is characterized in that: a fuse is arranged between the generator and the first normally open node.

The invention has the beneficial effects that: firstly, the characteristic that the voltage and the frequency of the generator gradually rise from low to high in the starting process is utilized to supply power to the alternating current motor, so that the problem that the current flowing through the alternating current motor is large when the alternating current motor is started is solved. And the first control button and the second control button are electrically and mechanically interlocked, so that two paths of power supplies are prevented from being simultaneously switched on. And thirdly, the safe power utilization of the power grid is ensured, and meanwhile, the mechanical impact during full-voltage starting is also avoided. Fourthly, secondary impact current can be avoided.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

The reference numbers indicate that the detection device 1, the starting control device 2, the generator control device 3, the commercial three-phase power L1, L2, L3, the motor M, the generator G, the fuse FU, the first contactor coil KM1, the first normally closed node B1, the first normally open node K1, the second contactor coil KM2, the second normally closed node B2, the second normally open node K2, the first control button SB1, the second control button SB2, the control power supply V and the power supply synchronization device 4.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

As shown in fig. 1, the generator soft start device for avoiding secondary inrush current of the present invention includes a detection device 1, a start control device 2, a generator control device 3, a power synchronization device 4, city three-phase power L1, L2, L3, a motor M, a generator G, a first contactor, a second contactor, a first control button SB1, and a second control button sb2, wherein the first contactor includes a first contactor coil KM1, a first normally closed node B1, and a first normally open node K1, the second contactor includes a second contactor coil KM2, a second normally closed node B2, and a second normally open node K2., and the city three-phase power L1, L2, and L3 is connected to the motor M through the first normally open node K1, the generator G is connected to the motor M through the second normally open node K2, and the detection device 1 is disposed at the side of the motor M for detecting an operation parameter of the motor M, such as the rotation speed of the motor M.

As shown in fig. 1, the start control device 2 is connected to the detection device 1 and the power source synchronization device 4, the output signal of the start control device 2 is respectively connected to the generator control device 3, the first control button SB1 and the second control button SB2, the first contactor coil KM1, the second normally closed node B2 and the first control button SB1 are connected in series and then connected to the control power source V, and the second contactor coil KM2, the first normally closed node B1 and the second control button SB2 are connected in series and then connected to the control power source V.

The control power supply V can be a 24V direct current power supply, and the first contactor and the second contactor are 24V direct current contactors. The control power source V of (2) may be 220V AC, and the first contactor and the second contactor are 220V AC contactors.

Fuse FU is preferably arranged between the three-phase power L1, L2, L3 and the first normally-open node K1 to ensure that the fuse FU automatically cuts off power when the motor normally operates, if an overcurrent phenomenon occurs, and the current is prevented from being overlarge due to mechanical clamping stagnation of the motor.

A fuse FU is preferably arranged between the generator G and the first normally-open node K1 to ensure automatic power off when overcurrent occurs during starting and prevent overlarge current caused by mechanical clamping stagnation of the motor.

Before starting the AC motor M, firstly controlling a generator control device 3 through a starting control device 2 so as to start a generator G, after the generator G is started successfully, the generator G works in an idle state, then closing a second control button SB2 through the starting control device 2, sending a low-frequency low-voltage power supply of the generator G into the AC motor M, starting the AC motor M to perform voltage reduction and frequency reduction starting (the voltage of a power supply output by the generator in the idle state is about 220V, the frequency is about 30Hz, and the voltage and the frequency in the idle state can be adjusted according to actual field conditions), after the AC motor M starts to rotate, controlling the motor M to be switched from the idle state to a rated speed, starting the voltage and the frequency of the power supply to be gradually increased, and gradually increasing the rotating speed of the AC motor M, when the voltage and the frequency of the generator G reach the rated values, the rotating speed of the AC motor M also reaches the rated values, finishing the starting process of the AC motor M, after finishing starting the AC motor M, starting the power supply synchronization device 4 starts to detect that the power supply of the generator G to output power supply signals of a commercial power supply L, L, 6303, controls the commercial power supply to be not to be started by a commercial power supply by a third-phase voltage, a third-adjustable voltage signal SB 463, a third-phase of the generator M3, a third-phase voltage of a third-phase voltage regulator SB 463, a third-adjustable-phase-adjustable motor III generator M-adjustable motor III-III generator M-III generator, a 369, a synchronous control device.