Motor star-delta step-down starting system

Abstract

The utility model discloses a motor star-delta step-down starting system comprising a step-down starting module which is composed of a step-down starting loop and a fixing structure. The voltage reduction starting loop is connected with a motor, a first motor contactor, a second motor contactor, a relay and a conversion structure. Wherein the first motor contactor is set to start in a star shape, and the second motor contactor is set to start in a triangular shape. The conversion structure can connect the first motor contactor or the second motor contactor to the voltage reduction starting loop. The relay controls movement of the conversion structure. The step-down starting loop is installed in the fixing structure, and the fixing structure enables the step-down starting module to be installed at the wiring position of the motor. According to the utility model, the first motor contactor and the second motor contactor are integrated, so that the device of the system is optimized; the step-down starting system is directly installed on one side of the motor, cables are saved, and the failure rate of equipment is reduced.

Description

Technical Field

[0001] The utility model relates to a star-delta voltage reduction starting system for a motor, belonging to the technical field of motor starting control equipment. Background Art

[0002] The current when the motor starts is approximately proportional to the stator voltage. Directly starting the motor will produce surge current, which will reduce the life of the equipment, and the sudden increase in torque will shorten the life of the machinery. In order to increase the service life of the device and protect the safety of on-site personnel, the decompression starting method is widely used to start the motor. There are many ways to start the motor with decompression, among which the star-delta decompression starting method has simple starting equipment and low cost. The motor can run when it is started in star-delta, and the rated torque can match the load, reducing power consumption.

[0003] In the traditional star-delta step-down starting system, two AC contactors are used between the star starter and the delta starter respectively. Certain cables are also required in the connection of the AC contactors. The installation of multiple contactors occupies a large space and is inconvenient to use.

[0004] See also Figure 7 , the three cables of the mains are connected to the motor control cabinet, which is equipped with a main switch and a traditional star-delta step-down starting system. The three cables of the mains are controlled by the main switch to be powered on. The three cables of the mains are connected to the traditional star-delta step-down starting system from the main switch, and the six cables are extended from the motor control cabinet after coming out of the traditional star-delta step-down starting system. The six cables coming out of the motor control cabinet are connected to the terminals at the connection of the motor after passing a distance. That is, the step-down starting system of the motor is usually directly set in the motor control cabinet. When connecting the step-down starting system to the six terminals of the motor, six cables need to be set. Under normal circumstances, the distance between the motor control cabinet and the motor is relatively far, and the six cables used at this time are very expensive. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a star-delta voltage reduction starting system for a motor, which solves the problem of high use cost of the traditional star-delta starting system.

[0006] The technical problem to be solved by the utility model is achieved by adopting the following technical solutions: a motor star-delta step-down starting system, comprising

[0007] A step-down starting module, the step-down starting module comprising a step-down starting circuit and a fixing structure, the step-down starting circuit being mounted on the fixing structure;

[0008] The step-down starting circuit is connected to a three-phase power supply, and is provided with a motor, a first motor contactor for controlling the motor to perform star-delta step-down, a second motor contactor, a relay, and a conversion structure for controlling the switching of the first motor contactor and the second motor contactor. The first motor contactor and the second motor contactor switch between star starting and delta starting, and the relay controls the movement of the conversion structure;

[0009] The reduced voltage starting module is installed at the connection point of the motor, not in the motor control cabinet.

[0010] Preferably, the first motor contactor and the second motor contactor form an integral structure.

[0011] Preferably, the conversion structure is installed inside the overall structure.

[0012] Preferably, the conversion structure is provided with a sensing device for providing movement of the conversion structure.

[0013] Preferably, the conversion structure is fixedly connected to the star starter when not controlled by the relay.

[0014] Preferably, the relay is a power-on delay relay, and the power-on delay relay can operate the induction device.

[0015] Preferably, the delay time of the power-on delay relay is 8-16 seconds.

[0016] Preferably, the fixing structure includes a first motor contactor fixing frame, a second motor contactor fixing frame, a control coil fixing frame, and a main fixing frame.

[0017] Preferably, the power-on delay relay operates the induction device to adjust the position of the conversion structure after the first motor contactor is started for a period of time.

[0018] Preferably, the first motor contactor fixing frame can accommodate the first motor contactor; the second motor contactor fixing frame can accommodate the second motor contactor; the control coil fixing frame can accommodate the control coil; and the overall fixing frame can accommodate the first motor contactor fixing frame, the second motor contactor fixing frame and the control coil fixing frame.

[0019] The beneficial effects of the utility model are:

[0020] (1) The utility model integrates the step-down starting module and can be directly installed on the motor. The step-down starting module is connected to the motor control cabinet with three cables. Compared with the six cables in the prior art, three cables are saved, which greatly reduces the number of connecting cables between the motor control cabinet and the motor and reduces the use cost.

[0021] (2) The utility model integrates the step-down starting module and can be directly installed on the motor, which can reduce the size of the motor control cabinet, thereby saving the production materials of the motor control cabinet and saving costs.

[0022] (3) Through the utility model, the conversion structure of the first motor contactor and the second motor contactor is improved. The second contactor controls the conversion of the first motor contactor or the second motor contactor to the circuit through the conversion structure, so that the first contactor can start the motor in a star start mode, reduce the voltage between each phase winding, and avoid excessive current damage to the equipment during startup. At the same time, after a period of star start operation, the second contactor can be converted to a triangle start to make the motor run at full voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an explosion diagram of the utility model.

[0024] Figure 2 It is an assembly diagram of the utility model.

[0025] Figure 3 It is a schematic diagram of the conversion structure of the utility model.

[0026] Figure 4 This is a schematic diagram of the assembly of the conversion structure of the utility model.

[0027] Figure 5 It is a structural schematic diagram of the conversion frame of the utility model.

[0028] Figure 6 It is a structural schematic diagram of the conversion block and the control coil fixing frame of the utility model.

[0029] Figure 7 The figure is a schematic diagram of the use of the prior art.

[0030] Figure 8 It is a schematic diagram of the use of the utility model.

[0031] Fig. 9 This is a physical diagram of the present utility model.

[0032] In the figure: 1-first motor contactor, 2-second motor contactor, 3-conversion frame, 4-control coil, 5-conversion block, 6-control coil fixing frame. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments.

[0034] Example 1

[0035] like Figure 1-Figure 6 As shown, the utility model proposes a motor star-delta step-down starting system, including

[0036] Step-down starting module. The step-down starting module consists of a step-down starting circuit and a fixed structure. The step-down starting circuit is installed on the fixed structure, and the fixed structure can be installed at the wiring of the motor. The step-down starting module is connected to the motor and can start the motor at a low voltage first, and then switch to the rated voltage to operate the motor after a period of time. The low voltage state can reduce the surge current generated when starting at full voltage, thereby increasing the service life of the equipment.

[0037] The step-down starting circuit is connected to a three-phase power supply, and is provided with a circuit master switch, a motor, a first motor contactor 1 for controlling the motor to perform star-delta step-down, a first motor contactor 2, a relay, and a conversion structure for controlling the switching of the first motor contactor 1 and the first motor contactor 2. The circuit formed after the first motor contactor 1 is connected to the circuit is star start; the circuit formed after the first motor contactor 2 is connected to the circuit is delta start. The relay controls the movement of the conversion structure. The step-down starting module is installed at the wiring of the motor, not in the motor control cabinet.

[0038] like Figure 8 As shown, three cables of the mains are connected to the motor control cabinet. A main switch is provided in the motor control cabinet. Whether the three cables of the mains are powered is controlled by the main switch. After coming out of the motor control cabinet, the three cables of the mains are connected to the step-down starting module. The step-down starting module is directly installed at the wiring location of the motor. Six cables coming out of the step-down starting module are connected to the terminal posts at the wiring location of the motor.

[0039] The first motor contactor 1 and the first motor contactor 2 form a whole, the conversion structure is installed between the first motor contactor 1 and the first motor contactor 2, and the relay controls the conversion structure and the first motor contactor 1 to be connected to the step-down starting circuit or the first motor contactor 2 to be connected to the step-down starting circuit.

[0040] The relay is a power-on delay relay and a control coil 4 controlled by the power-on delay relay. The power-on delay relay is connected to the control coil 4, and the control coil 4 is arranged in the middle of the conversion structure. The conversion structure fixes the first motor contactor 1 to be connected to the step-down starting circuit when it is not controlled by the power-on delay relay. After the power-on delay relay is triggered, the control coil 4 generates magnetic force, and the magnetic force attracts the conversion structure to disconnect the first motor contactor 1 from the step-down starting circuit, and connects the first motor contactor 2 to the step-down starting circuit. The step-down starting circuit is converted from star starting to triangle starting. The delay time of the power-on delay relay is adjusted according to the power of the motor, usually 8-16 seconds, and 15 seconds is used in this embodiment. After the step-down starting circuit is connected, the power-on delay relay is triggered according to the set time delay, the first motor contactor 2 is connected to the step-down starting circuit and the connection between the first motor starter and the step-down starting circuit is disconnected, so that the step-down starting circuit is converted from star starting to triangle starting.

[0041] like Figure 3-Figure 6 As shown, the conversion structure is composed of a conversion block 5, a magnet, a spring, and a conversion frame 3. The conversion frame 3 and the conversion block 5 are made of metal. The conversion frame 3 and the conversion block 5 are connected by a pin. A control coil 4 controlled by a power-on delay relay is arranged between the conversion block 5 and the conversion frame 3, and the control coil 4 is connected to the fixed block after being started. When the control coil 4 is not started, the conversion structure is connected to the first motor contactor 1 through the magnet and the spring.

[0042] like Figure 5 As shown. The structure of the conversion frame 3 is as follows: a metal sheet is arranged at the top, and the shape of the metal sheet is rectangular; metal feet extending downward are arranged at the four corners of the long side of the rectangle, and the metal feet are in the shape of a sheet, and the thickness is the same as that of the metal sheet at the top, and the metal feet extend from the end point of the long side of the rectangle to the long side. The distance between the metal feet of the wide side is the same as the distance between the control coils 4. The metal feet extend downward for a distance and then bend 90 degrees, and then bend 90 degrees and extend downward after being away from the rectangle for a distance in the horizontal direction. When bending from the horizontal direction to the vertical direction, the metal feet will also be offset to the outside of the long side of the rectangle for a distance. At this time, the distance between the metal feet of the wide side is slightly wider than the control coil 4, and can accommodate the control coil 4. The length of the downward extension again is higher than the height of the control coil 4. An opening 1 is arranged at the bottom of the metal foot. An extension frame with the same extension direction as the metal foot and the same extension distance as the distance before the metal foot is bent is arranged in the middle section of the long side of the top metal sheet, and an opening 2 is arranged on the extension frame.

[0043] A magnet is arranged between the two extension frames, and an opening three is arranged in the middle of the magnet, and the opening three in the middle of the magnet has the same diameter as the opening two of the extension frame. Pin one passes through the magnet and fixes the magnet between the conversion frames 3. Pin one also passes through the opening two and is fixed in the first motor contactor 2. A fixing plate is arranged at the installation position between the first motor contactor 2 and the conversion frame 3, and the fixing plate is arranged below the extension frame, and notches matching the first motor contactor 2 are arranged on both sides of the fixing plate. It is fixed in the first motor contactor 2 through the notch. The fixing plate can assist the extension frame in being fixed in the first motor contactor 2; and reduce the influence of magnetic forces in other directions generated when the control coil 4 is started on the conversion structure.

[0044] The structure of the conversion block 5 is: a cuboid, the lengths of the long sides and wide sides of the cuboid are consistent with the metal sheet at the top of the conversion frame 3, and the height of the cuboid is consistent with the length of the wide side. The bottom of the cuboid is provided with a boss 1 whose height is the same as the distance the metal foot is offset to the outside, and the boss 1 is provided at both ends of the bottom of the cuboid. The bosses 1 at both ends are provided with pins 1 that pass through the wide side, and the pins 1 can be fixed with the openings 1 of the conversion frame 3 so that the relative position between the conversion block 5 and the conversion frame 3 does not change when the conversion structure is working. The fixing block is provided with pins 2 that pass through the wide side in the middle near the top, and the conversion block 5 is fixed in the first motor contactor 1 by pins 2. A boss 2 is provided in the middle section of the bottom end of the conversion block 5, and the spring is fixed by boss 2.

[0045] The spring is arranged between the conversion block 5 and the conversion frame 3. One end of the spring is connected to the conversion block 5, and the other end is connected to the control coil 4.

[0046] The conversion block 5 and the conversion frame 3 are respectively arranged in the first motor contactor 1 and the first motor contactor 2, and control the first motor contactor 1 or one of the first motor contactor 2 to access the step-down starting circuit. The conversion block 5 is arranged on the side close to the first motor contactor 1, and the conversion frame 3 is arranged on the side of the first motor contactor 2. The first motor contactor 2 is provided with a connecting plate on the side of the installation extension frame. The connecting plate is connected to the magnet, and the connecting plate auxiliary magnet is connected to the control coil 4. The magnet and the spring fix the conversion structure on one side of the first motor contactor 1 when the control coil 4 is not started, so that the first motor contactor 1 is connected to the step-down starting circuit.

[0047] After the control coil 4 is started, it will be magnetic and attract the conversion block 5 to the control coil 4. At this time, the conversion block 5 releases the connection between the first motor contactor 1 and the step-down starting circuit; the conversion block 5 drives the conversion frame 3 to move, and at this time the conversion frame 3 controls the first motor contactor 2 to connect to the step-down starting circuit.

[0048] The fixed structure includes a first motor contactor fixing frame of the first motor contactor 1, a second motor contactor fixing frame of the first motor contactor 2, a control coil fixing frame 6 of the control coil 4, and a general fixing frame capable of accommodating the first motor contactor fixing frame, the second motor contactor fixing frame, and the control coil fixing frame 6 and fixing them. The structures of the first motor contactor fixing frame, the second motor contactor fixing frame, and the control coil fixing frame 6 are based on the existing fixed structure, and the structures of the original first motor contactor fixing frame, the second motor contactor fixing frame, and the control coil fixing frame 6 are not changed. The position between the second motor contactor fixing frame and the fixing plate is fixed by the notch and the protrusion originally provided on the second motor contactor fixing frame, and the movement of the conversion device after fixing cannot change the position between the second motor contactor fixing frame and the fixing plate. A plurality of grooves are arranged on the inner side of the control coil fixing frame 6, wherein the metal feet are arranged in the grooves, and the control coil fixing frame 6 is slidably connected with the metal feet on the conversion frame 3. When the conversion frame 3 moves, it is restricted by the grooves on the control coil fixing frame 6, and the conversion structure is restricted to move in the set direction.

[0049] The step-down starting circuit is connected to the three-phase power supply through the circuit master switch. The three-phase power supply is connected to the motor that needs step-down starting after passing through the circuit master switch. The terminals of the first motor contactor 2 include the power supply side of the first motor contactor 2: L1, L2, L3; the load side of the first motor contactor 2: T1, T2, T3. Among them, the power supply side L1, L2, L3 of the first motor contactor 2 of the first motor contactor 2 is connected to the three-phase power supply controlled by the circuit master switch, and the power supply side L1, L2, L3 of the first motor contactor 2 is also connected to the motor U1, V1, W1 terminal. The load side T1, T2, T3 of the first motor contactor 2 is connected to the motor U2, V2, W2 terminal. The terminals of the first motor contactor 1 include the power supply side of the first motor contactor 1: L4, L5, L6; the load side of the first motor contactor 1: T4, T5, T6. Among them, L4, L5, L6 of the first motor contactor 1 are connected to the load side T1, T2, T3 of the second contactor respectively; the load side of the first motor contactor 1: T4, T5, T6 are respectively short-circuited by lines. A protection device is also connected in series between the circuit main switch and the first motor contactor 2. The protection device is a thermal relay FR, the purpose of which is to ensure current safety.

[0050] A control coil 4 controlled by a relay is arranged between the first motor contactor 1 and the first motor contactor 2, wherein the first motor contactor 1, the control coil 4, and the second motor controller are connected and fixed by the first motor contactor fixing frame, the control coil fixing frame 6, and the second motor contactor fixing frame, respectively. A conversion structure is arranged between the first motor contactor 1 and the first motor contactor 2, and the control coil 4 passes through the conversion structure. When the control coil 4 is not started, the conversion structure connects the first motor contactor 2 to the step-down starting circuit. At the same time, the first motor contactor 1 is not connected to the step-down starting circuit.

[0051] The connection method between the control coil 4 and the power-on delay relay is to set two lines connected to L1 and L2 between the circuit main switch and the thermal relay FR and connect them to the power-on delay relay, and the power-on delay relay is provided with two lines connected to the control coil 4.

[0052] When the motor needs to be started, turn on the main circuit switch. At this time, the power supply side L1, L2, L3 of the first motor contactor 2 are connected to the motor U1, V1, W1 terminals respectively, and the load side of the first motor contactor 2: T1, T2, T3 are connected to the motor U2, V2, W2 terminals respectively. The state of the first motor contactor 2 is disconnected. The state of the first motor contactor 1 is connected. At this time, the starting torque of the motor is reduced to 1 / 3 of the original. At this time, the step-down starting system is a star start.

[0053] At the same time, the power-on delay relay starts timing, and when the set time is reached, the control coil 4 will be triggered. The control coil 4 starts to disconnect the first motor contactor 1 from the step-down starting circuit, and connects the first motor contactor 2 to the step-down starting circuit. When the control coil 4 starts, the conversion block 5 of the conversion structure is attracted to one side of the control coil 4. At this time, the step-down system is converted from star starting to triangle starting.

[0054] The main fixing frame can accommodate the first motor contactor fixing frame, the second motor contactor fixing frame, and the control coil fixing frame 6. The main fixing frame connects the overall structure of the step-down starting system together. After being combined together, it can be installed to the wiring of the motor through the main fixing frame. The distance between the step-down starting device and the motor is reduced, and the cables between the step-down starting system and the motor can be reduced. The first motor contactor 1 and the first motor contactor 2 form a whole. The cables connected between the first motor contactor 1 and the first motor contactor 2 can be reduced, and at the same time, the distance between the step-down starting system and the motor is reduced, thereby reducing costs.

[0055] The main bracket can also protect the step-down starting system. When the device is in use, the different working environment may cause damage to the devices inside the step-down starting system, such as: inductively charged conductors or rotating cooling fans touching and causing or leading to electrical or mechanical damage. Reduce internal moisture, dirt or other air pollutants that may harm working components.

[0056] The main bracket has the function of heat dissipation. When the star-delta step-down system is in use, a certain degree of heat will be generated. When the heat accumulates to a certain degree, it will affect the efficiency of the device and increase the cost of use. The main bracket can transfer the heat generated during the operation of the star-delta step-down starting system to the outside to reduce heat accumulation. When the operating system fails and generates a lot of heat, the heat dissipation function does not affect the function of the thermal relay FR to protect the step-down starting system.

[0057] The above shows and describes the basic principles, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited to the above embodiments. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of protection claimed by the utility model. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A motor star-delta step-down starting system, comprising: The step-down starting module is characterized by: The step-down starting module comprises a step-down starting circuit and a fixed structure, and the step-down starting circuit is installed on the fixed structure; The step-down starting circuit is connected to a three-phase power supply, and is provided with a motor, a first motor contactor for controlling the motor to perform star-delta step-down, a second motor contactor, a relay, and a conversion structure for controlling the switching of the first motor contactor and the second motor contactor. The first motor contactor and the second motor contactor switch between star starting and delta starting, and the relay controls the movement of the conversion structure; The reduced voltage starting module is installed at the connection point of the motor, not in the motor control cabinet.

2. The motor star-delta step-down starting system according to claim 1, characterized in that: The first motor contactor and the second motor contactor form an integral structure.

3. The motor star-delta step-down starting system according to claim 2, characterized in that: The conversion structure is installed inside the overall structure.

4. The motor star-delta step-down starting system according to claim 1, characterized in that: The conversion structure is provided with a sensing device for providing movement of the conversion structure.

5. The motor star-delta step-down starting system according to claim 4, characterized in that: The switching structure is fixedly connected to the star starter when not controlled by the relay.

6. The motor star-delta step-down starting system according to claim 4, characterized in that: The relay is a power-on delay relay, and the power-on delay relay can operate an induction device.

7. The motor star-delta step-down starting system according to claim 6, characterized in that: The delay time of the power-on delay relay is 8-16 seconds.

8. The motor star-delta step-down starting system according to claim 1, characterized in that: The fixing structure comprises a first motor contactor fixing frame, a second motor contactor fixing frame, a control coil fixing frame, and a general fixing frame.

9. A motor star-delta step-down starting system according to any one of claims 1 to 8, characterized in that: The power-on delay relay operates the sensing device to adjust the position of the switching structure after the first motor contactor is started for a period of time.

10. The motor star-delta step-down starting system according to claim 9, characterized in that: The first motor contactor fixing frame can accommodate the first motor contactor; the second motor contactor fixing frame can accommodate the second motor contactor; the control coil fixing frame can accommodate the control coil; The main fixing frame can accommodate the first motor contactor fixing frame, the second motor contactor fixing frame and the control coil fixing frame.

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