Star-delta step-down starting circuit demonstration experiment table

Abstract

The utility model provides a star-delta step-down starting circuit demonstration experiment table, which comprises an assembly display board used for installing and fixing electric appliance elements, a fixing seat and a star-delta step-down starting circuit, the electric appliance elements in the star-delta step-down starting circuit are installed on the assembly display board, and the corresponding electric appliance elements are connected through wires; and the assembly display board is mounted on the fixed seat.

Description

Technical Field

[0001] The utility model relates to teaching aids, in particular to a star-delta step-down starting circuit demonstration experimental platform. Background Art

[0002] In the field of electrical engineering teaching, such as the field of star-delta step-down starting technology, there is currently no dedicated experimental bench. Students only read textbooks and listen to teachers' explanations, and cannot deeply and effectively understand the control circuits and functions of related circuits. In order to improve the quality of teaching, it is urgent to provide experimental equipment that can display circuits and perform actual power-on demonstrations. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a star-delta step-down starting circuit demonstration test bench.

[0004] A star-delta step-down starting circuit demonstration test bench comprises an assembly display board for mounting and fixing electrical components, a fixing base, and a star-delta step-down starting circuit. The electrical components in the star-delta step-down starting circuit are mounted on the assembly display board, and the corresponding electrical components are connected by wires. The assembly display board is mounted on the fixing base.

[0005] Furthermore, the star-delta step-down starting circuit demonstration test bench, wherein: the star-delta step-down starting circuit includes a frequency converter control circuit and a motor control circuit;

[0006] The inverter control circuit includes the inverter, the inverter delay start relay KA, the RP adjustable potentiometer, the normally closed inverter stop button, the normally open inverter start button, and a 24V external DC power supply. The inverter's mains input terminal is used to connect to a 220V two-phase mains power supply, and the inverter's three-phase power supply output terminal is used to connect to the power supply input terminal of the motor control circuit; the connection pins on both sides of the second normally open node KA-2 of the inverter delay start relay KA correspond to the start / stop control signal input terminal and the inverter's ground terminal, respectively; the two ends of the RP adjustable potentiometer are connected to the inverter's electrical signal output terminal and ground terminal, respectively, and the adjustable terminal of the RP adjustable potentiometer is connected to the inverter's drive signal input terminal; the series circuit formed by the inverter stop button, the inverter start button, and the coil of the inverter delay start relay KA is connected between the 24V external DC power supply and ground, and the first normally open contact KA-1 of the inverter start / stop relay is connected in parallel to both ends of the inverter start button to form a self-locking circuit;

[0007] The motor control circuit is divided into the main power supply circuit and the control circuit. The motor control circuit includes the circuit breaker QF, the main power supply contactor KM1, the thermal relay FR, the motor stop button SB1, the motor start button SB2, the main contactor KM1, the star contactor KM2, the angular contactor KM3, and the time relay KT;

[0008] Main power supply circuit: The L1 phase line of the power supply output terminal of the inverter is connected to the L1 phase line input side contact of the circuit breaker QF, the L1 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the first normally open contact of the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the first normally open contact of the three normally open contacts of the main contactor KM1 is connected to the L1 phase line input side contact of the thermal relay FR, and the L1 phase line output side contact of the thermal relay FR is connected to the power supply input terminal U1 pin of the motor M;

[0009] The L2 phase line of the power supply output terminal of the frequency converter is connected to the L2 phase line input side contact of the circuit breaker QF, the L2 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the second normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the second normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L2 phase line input side contact of the thermal relay FR, and the L2 phase line output side contact of the thermal relay FR is connected to the power supply input terminal V1 pin of the motor M;

[0010] The L3 phase line of the power supply output terminal of the inverter is connected to the L3 phase line input side contact of the circuit breaker QF, the L3 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the third normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the third normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L3 phase line input side contact of the thermal relay FR, and the L3 phase line output side contact of the thermal relay FR is connected to the power supply input terminal W1 pin of the motor M;

[0011] The three normally open contacts of the angular contactor KM3 are connected in parallel with the motor M: the first normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal U1 pin of the motor M and the neutral line terminal U2 pin of the motor M, the second normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal V1 pin of the motor M and the neutral line terminal V2 pin of the motor M; the third normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal W1 pin of the motor M and the neutral line terminal W2 pin of the motor M;

[0012] The neutral terminals U2, V2, and W2 of the motor M are connected in series with the first, second, and third normally open contacts of the three-pronged normally open contacts of the star contactor KM2, and the star is closed;

[0013] The control circuit is connected between the L1 phase line of the power supply output terminal of the inverter and the ground neutral line N. The control circuit includes the main contactor control branch, the star contactor control branch, and the angular contactor control branch;

[0014] The main contactor control branch includes a series circuit composed of the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1, the normally open motor start button SB2 and the coil of the main contactor KM1 in turn, the L1 phase line is connected to the power input side pin A2 of the normally closed contact of the thermal relay FR, and the power output side pin A1 of the coil of the main contactor KM1 is connected to the ground zero line N; the single-throw normally open contact KM1-1 of the main contactor KM1 is connected in parallel with the start button SB2 to form a self-locking circuit.

[0015] The star contactor control branch includes a series circuit composed of the normally closed contact KM3-2 of the angular contactor KM3, the normally closed contact of the time relay KT and the coil of the star contactor KM2 in turn, the power input side pin of the normally closed contact KM3-2 of the angular contactor KM3 is connected to the power output side pin of the start button SB2, and the power output side pin A1 of the coil of the star contactor KM2 is connected to the ground zero line N; the coil of the time relay KT is connected in parallel across the series circuit composed of the normally closed contact of the time relay KT and the coil of the star contactor KM2.

[0016] The angular contactor control branch includes a series circuit composed of the normally closed contact KM2-1 of the star contactor KM2, the normally open contact of the time relay KT and the coil of the angular contactor KM3 in turn, the power input side pin of the normally closed contact KM2-1 of the star contactor KM2 is connected to the power output side pin of the start button SB2, and the power output side pin A1 of the coil of the angular contactor KM3 is connected to the ground zero line N; the normally open contact KM3-1 of the angular contactor KM3 is connected in parallel with the normally open contact of the time relay KT to form a self-locking circuit.

[0017] When the start button of the frequency converter and the motor start button SB2 are pressed, the power input end of the frequency converter inputs 220V power, the coil of the time delay start relay KA of the frequency converter is powered, after the second normally open contact KA-2 of the time delay start relay KA is time-delayed and attracted, the start-stop control signal input end DI1 of the frequency converter is connected to the ground, the start-stop control signal input end DI1 of the frequency converter changes from high level to low level, the frequency converter receives the low level signal, controls the three-phase power supply output end of the frequency converter to output a three-phase power supply signal to the power supply input end of the motor control circuit, the L1 phase line of the three-phase power supply output end of the frequency converter is powered, and the electric signal reaches the coil of the main contactor KM1 through the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1 and the connected motor start button SB2, the first, second and third normally open contacts of the main contactor KM1 are closed at the same time, and the single-throw normally open contact KM1-1 of the main contactor KM1 is closed to form a self-locking circuit with the start button SB2.

[0018] Meanwhile, the electric signal reaches the coil of the star contact KM2 through the closed angular contact KM3-2 and the normally closed contact of the time relay KT, the coil of the star contact KM2 is electrified, the three normally open contacts of the star contact KM2 are closed, the motor M enters the star starting state; meanwhile, the electric signal reaches the coil of the time relay KT through the closed angular contact KM3-2, the time relay KT starts timing, the normally open contact of the time relay KT keeps open before the timing time is up, the normally closed contact of the time relay KT keeps closed before the timing time is up; the time relay KT is timed up, the normally open contact of the time relay KT is closed, the electric signal reaches the coil of the angular contact KM3 through the normally closed contact KM2-1 of the star contact KM2 and the currently closed normally open contact of the time relay KT, the coil of the angular contact KM3 is electrified, the normally open contact KM3-1 of the angular contact KM3 is closed, forming a self-locking circuit, meanwhile, the normally closed contact KM3-2 of the angular contact KM3 is opened, the coil of the star contact KM2 is de-energized, the three normally open contacts of the star contact KM2 are opened, the star starting state of the motor M is stopped, and the motor M enters the angular starting state.

[0019] Further, the star-delta step-down starting circuit demonstration experiment table, wherein the fixed seat and the assembly display board are combined into a table, the table includes a storage table hopper, and the assembly display board is a table top covering the table, and the assembly display board is movably connected with the storage table hopper.

[0020] Further, the star-delta step-down starting circuit demonstration experiment table, wherein the storage table hopper includes a storage space with an opening facing the sky.

[0021] Further, the star-delta step-down starting circuit demonstration experiment table, wherein a slot is arranged on one side of the storage table hopper for mounting and supporting the assembly display board, and an inner slot width of the slot is matched with a thickness of the assembly display board.

[0022] Further, the star-delta step-down starting circuit demonstration experiment table, wherein the one side of the storage table hopper and the assembly display board are connected through a hinge.

[0023] Further, the star-delta step-down starting circuit demonstration experiment table, wherein the one side of the storage table hopper and the assembly display board are connected through a hinge.

[0024] Further, the star-delta step-down starting circuit demonstration experiment table, wherein the one side of the storage table hopper and the assembly display board are connected through a hinge.

[0025] Furthermore, the star-delta step-down starting circuit demonstration test bench, wherein: the assembly display board is provided with a mounting hole matrix, the mounting hole matrix is ​​mounting holes evenly arranged in the horizontal and vertical directions, and is used to install and fix electrical components.

[0026] Furthermore, the star-delta step-down starting circuit demonstration test bench, wherein: the assembly display board is provided with horizontal or vertical long strip hollow holes.

[0027] The star-delta step-down starting circuit demonstration test bench provided by the utility model can realize on-site demonstration by opening the assembly display board, installing the electrical components on the assembly display board, correctly connecting the circuit and connecting the power supply, thereby achieving the purpose of dynamically demonstrating teaching content; compared with the teaching mode of picture and language teaching, the utility model transforms the teaching content from the traditional static to dynamic, which is more intuitive and effective, and is convenient for improving teaching efficiency and enhancing teaching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a circuit diagram of the motor control circuit in the star-delta step-down starting circuit demonstration test bench provided by the utility model;

[0029] Figure 2 This is the circuit principle diagram of the inverter control loop in the star-delta step-down starting circuit demonstration test bench provided by the utility model;

[0030] Figure 3 This is an assembly schematic diagram on an assembly display board of an embodiment. DETAILED DESCRIPTION

[0031] The utility model provides a star-delta step-down starting circuit demonstration test bench, comprising an assembly display board for mounting and fixing electrical components, a fixing base, and a star-delta step-down starting circuit. The electrical components in the star-delta step-down starting circuit are mounted on the assembly display board, and the corresponding electrical components are connected by wires; the assembly display board is mounted on the fixing base.

[0032] The star-delta step-down starting circuit includes a frequency converter control circuit and a motor control circuit;

[0033] The inverter control circuit is as follows Figure 2, including the inverter, the inverter delay start relay KA, the RP adjustable potentiometer, the normally closed inverter stop button, the normally open inverter start button, and the 24V external DC power supply. The AC input terminal of the inverter is used to connect to the 220V AC two-phase power supply, and the three-phase power supply output terminal of the inverter is used to connect to the power supply input terminal of the motor control circuit; the connection pins on both sides of the second normally open node KA-2 of the inverter delay start relay KA correspond to the start and stop control signal input terminal of the inverter and the ground terminal of the inverter respectively; the RP adjustable potentiometer The two ends of the potentiometer are connected to the inverter's electrical signal output terminal (pin marked as +10 in the figure) and ground terminal com respectively. The adjustable terminal of the RP adjustable potentiometer is connected to the inverter's drive signal input terminal (pin marked as AL1 in the figure). The series circuit formed by the inverter's stop button, inverter start button, and the coil of the inverter's delayed start relay KA is connected between the 24V external DC power supply and ground. The first normally open contact KA-1 of the inverter's start-stop relay is connected in parallel to both ends of the inverter's start button to form a self-locking circuit.

[0034] The motor control circuit is divided into the main power supply circuit and the control circuit. The motor control circuit includes the circuit breaker QF, the main power supply contactor KM1, the thermal relay FR, the motor stop button SB1, the motor start button SB2, the main contactor KM1, the star contactor KM2, the angular contactor KM3, and the time relay KT;

[0035] Main power supply circuit, such as Figure 1 : The L1 phase line of the power supply output terminal of the inverter is connected to the L1 phase line input side contact pin 5 of the circuit breaker QF, the L1 phase line output side contact pin 6 of the circuit breaker QF is connected to the electric energy signal input side contact pin 5 of the first normally open contact of the three normally open contacts of the main contactor KM1, the electric energy signal output side contact pin 6 of the first normally open contact of the three normally open contacts of the main contactor KM1 is connected to the L1 phase line input side contact pin 5 of the thermal relay FR, and the L1 phase line output side contact pin 6 of the thermal relay FR is connected to the power supply input terminal U1 pin of the motor M;

[0036] The L2 phase line of the power supply output terminal of the inverter is connected to the L2 phase line input side contact pin 3 of the circuit breaker QF, the L2 phase line output side contact pin 4 of the circuit breaker QF is connected to the electric energy signal input side contact pin 3 of the second normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact pin 4 of the second normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L2 phase line input side contact pin 3 of the thermal relay FR, and the L2 phase line output side contact pin 4 of the thermal relay FR is connected to the power supply input terminal V1 pin of the motor M;

[0037] The L3 phase line of the power supply output terminal of the inverter is connected to the L3 phase line input side contact pin 1 of the circuit breaker QF, the L3 phase line output side contact pin 2 of the circuit breaker QF is connected to the electric energy signal input side contact pin 1 of the third normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact pin 2 of the third normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L3 phase line input side contact pin 1 of the thermal relay FR, and the L3 phase line output side contact pin 2 of the thermal relay FR is connected to the power supply input terminal W1 pin of the motor M;

[0038] The three normally open contacts of the angular contactor KM3 are connected in parallel with the motor M: the first normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal U1 pin of the motor M and the neutral line terminal U2 pin of the motor M, the second normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal V1 pin of the motor M and the neutral line terminal V2 pin of the motor M; the third normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal W1 pin of the motor M and the neutral line terminal W2 pin of the motor M;

[0039] The neutral terminals U2, V2, and W2 of the motor M are connected in series with the first, second, and third normally open contacts of the three-pronged normally open contacts of the star contactor KM2, and the star is closed;

[0040] The control circuit is connected between the L1 phase line of the power supply output terminal of the inverter and the ground neutral line N. The control circuit includes the main contactor control branch, the star contactor control branch, and the angular contactor control branch;

[0041] The main contactor control branch includes a series circuit consisting of the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1, the normally open motor start button SB2, and the coil of the main contactor KM1, which are connected in series in sequence. The phase line L1 is connected to the power input side pin A2 of the normally closed contact of the thermal relay FR, and the power output side pin A1 of the coil of the main contactor KM1 is connected to the ground neutral line N. The single-pole normally open contact KM1-1 of the main contactor KM1 is connected in parallel with the start button SB2 to form a self-locking circuit.

[0042] The star contactor control branch includes a series circuit formed by the normally closed contact KM3-2 of the angular contactor KM3, the normally closed contact of the time relay KT, and the coil of the star contactor KM2, connected in series in sequence. The power input pin of the normally closed contact KM3-2 of the angular contactor KM3 is connected to the power output pin of the start button SB2, and the power output pin A1 of the coil of the star contactor KM2 is connected to the grounded neutral line N. The two ends of the coil of the time relay KT are connected in parallel to the two ends of the series circuit formed by the normally closed contact of the time relay KT and the coil of the star contactor KM2.

[0043] The angular contactor control branch includes a series circuit formed by connecting the normally closed contact KM2-1 of the star contactor KM2, the normally open contact of the time relay KT, and the coil of the angular contactor KM3 in series. The power input pin of the normally closed contact KM2-1 of the star contactor KM2 is connected to the power output pin of the start button SB2, and the power output pin A1 of the coil of the angular contactor KM3 is connected to the grounded neutral line N. The normally open contact KM3-1 of the angular contactor KM3 is connected in parallel with the normally open contact of the time relay KT to form a self-locking circuit.

[0044] Press the inverter start button and the motor start button SB2 to turn on the inverter. The inverter mains input terminal inputs 220V mains power. The coil of the inverter delayed start relay KA is energized. After the second normally open contact KA-2 of the inverter delayed start relay KA is delayed and closed, the inverter start and stop control signal input terminal DI 1 is connected to the ground terminal. The inverter start and stop control signal input terminal DI 1 high level is converted to low level. The inverter receives the low level signal and controls the three-phase power supply output terminal of the inverter to output a three-phase power supply signal to the power supply input terminal of the motor control circuit. The L1 phase line of the three-phase power supply output terminal of the inverter is energized. The electrical signal reaches the coil of the main contactor KM1 through the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1, and the connected motor start button SB2. The first, second, and third normally open contacts of the three-way normally open contacts of the main contactor KM1 are closed at the same time, and the single normally open contact KM1-1 of the main contactor KM1 is closed, forming a self-locking circuit with the start button SB2;

[0045] At the same time, the electrical signal reaches the coil of the star contactor KM2 through the closed normally closed contact KM3-2 of the angular contactor and the normally closed contact of the time relay KT. The coil of the star contactor KM2 is energized, the three-way normally open contact of the star contactor KM2 is closed, and the motor M enters the star starting state; at the same time, the electrical signal reaches the coil of the time relay KT through the closed normally closed contact KM3-2 of the angular contactor, and the time relay KT starts timing. The normally open contact of the time relay KT remains in the open state before the timing time expires, and the normally closed contact of the time relay K remains in the closed state before the timing time expires; when the timing of the time relay KT expires, the normally open contact of the time relay KT closes. When the motor starts, the electric signal reaches the coil of the angular contactor KM3 through the normally closed contact KM2-1 of the star contactor KM2 and the normally open contact of the time relay KT. The coil of the angular contactor KM3 is energized, and the normally open contact KM3-1 of the angular contactor KM3 is closed, forming a self-locking circuit. At the same time, the normally closed contact KM3-2 of the angular contactor KM3 is disconnected, the coil of the star contactor KT is de-energized, and the coil of the time relay KT is de-energized; at the same time, the normally closed contact KM3-2 of the angular contactor KM3 is disconnected, the coil of the star contactor KM2 is de-energized, and the three-way normally open contact of the star contactor KM2 is disconnected. The star start state of the motor M stops, and the motor M enters the angle start state.

[0046] In one embodiment, a support column is provided on each side of the fixing seat, and a vertical through groove is provided on the opposite inner sides of the two support columns. The front faces of the two vertical through grooves are opposite and have the same specifications. The assembled display board is used to be inserted into the two vertical through grooves and fixed.

[0047] The assembly display board may include two or more assembly display boards, and each assembly display board is sequentially inserted into two vertical through grooves and fixed.

[0048] In another embodiment, the fixing base is a table including a tabletop and supporting legs. A supporting plate is provided on each side of the tabletop. The supporting plates are provided with connectors. The assembled display board is attached to the two supporting plates and fixed on both sides by the connectors.

[0049] In another embodiment, the fixing base and the assembly display board are combined into a table, the table includes a storage drawer, the assembly display board is a tabletop covering the table, and the assembly display board and the storage drawer are movably connected.

[0050] The storage table drawer includes a storage space that opens toward the sky.

[0051] A through groove for installing and supporting the assembly display board is provided on one side of the storage table drawer, and the inner groove width of the through groove matches the thickness of the supported assembly display board.

[0052] In addition, one side of the storage table drawer and the assembly display board can be connected through a loose-leaf connection.

[0053] In another embodiment, one side of the storage table drawer is connected to the assembly display board via a hinge.

[0054] In another embodiment, the storage table drawer and the assembly display board are connected via a pneumatic rod.

[0055] The assembly display board is provided with a mounting hole matrix, which is mounting holes evenly arranged in the horizontal and vertical directions and is used for mounting and fixing electrical components.

[0056] In another embodiment, the assembly display board is provided with horizontal or vertical long strip hollow holes. Figure 3 The assembly diagram of the assembly display board is shown.

[0057] In the control circuit of the utility model technical solution:

[0058] 1. Any live wire and neutral wire N of the 380V power supply can be used as a 220V control power supply (relays KM1, KM2, and KM3 are all 220V low-voltage devices)

[0059] 2. Main contactor control branch: The live wire L first passes through the normally closed point of the FR thermal relay, the normally closed point of the stop button SB1 and the normally open point of the start button SB2 in series, and forms a self-locking with the normally open point of the contactor KM1, and then enters the A2 end of the contactor KM1 coil as shown in the figure;

[0060] 3. Connect the neutral wire to the A1 terminal of relays KM1, KM2, and KM3 and the neutral wire terminal 2 of the time relay respectively;

[0061] 4. Star contactor control branch: According to the diagram, take power from the lower end of the stop button SB1, enter the normally closed point of relay KM3, the normally closed points 1 and 4 of the time relay KT, and then transmit it to the coil A2 end of contactor KM2, and connect time relays 1 and 7 at the same time;

[0062] Inverter: This inverter is a single-phase Delta inverter. Control mode: 1. Start and stop are controlled by the intermediate relay open point control inverter signal input DI 1 terminal. 2. Inverter main circuit: Input power is single-phase 220V, output U, V, W terminals three-phase 220V;

[0063] RP is a potentiometer that adjusts the motor frequency (not less than 20Hz). When the intermediate relay KA is turned on, the inverter will start slowly for 10 seconds and then run normally (the motor wiring method is angle type);

[0064] Inverter parameters:

[0065] 1. Circuit breaker QF, as it has short circuit and overload functions, does not use a fuse.

[0066] 2. For teaching safety needs, the control power supply is simulated 220V voltage, and the contactors KM1, KM2, KM3 and time relay KT are all DC24V.

[0067] 3. The thermal relay is of conventional type, and the switching power supply is 220V input and 24V output.

[0068] 4. The test bench can also be used for maintenance and troubleshooting.

[0069] Circuit Working Principle: This circuit meets the requirements of both easy motor starting and strong power. When the start button is pressed, the main contactor KM1, star contactor KM2, and time relay KT operate. When the set time is reached, the star contactor KM2 stops and the angle contactor KM3 closes. Here, the star position makes the motor easy to start, and the angle position provides strong power.

[0070] By comparing star-delta step-down starting and frequency converter, frequency converter control is simpler and easier to operate, but star-delta starting cost is much lower. Each has its own needs.

[0071] The inverter start and stop control is controlled by the opening point of the intermediate relay. Press the start button KA to turn on the inverter and start the motor. Press the stop button KA to disconnect the inverter and stop the motor.

[0072] The inverter model is Siemens G120, the power supply is single-phase 220V; the motor is axial flow fan 200FZY4-D 380V65W; the RP potentiometer is a speed potentiometer.

[0073] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A star-delta step-down starting circuit demonstration test bench, characterized by: It includes an assembly display board for mounting and fixing electrical components, a fixing base, and a star-delta step-down starting circuit. The electrical components in the star-delta step-down starting circuit are mounted on the assembly display board, and the corresponding electrical components are connected by wires; the assembly display board is mounted on the fixing base; The star-delta step-down starting circuit includes a frequency converter control circuit and a motor control circuit; The inverter control circuit includes the inverter, the inverter delay start relay KA, the RP adjustable potentiometer, a normally closed inverter stop button, a normally open inverter start button, and a 24V external DC power supply. The inverter's mains input is used to connect to a 220V two-phase mains power supply, and the inverter's three-phase power supply output is used to connect to the power supply input of the motor control circuit; the connection pins on both sides of the second normally open node KA-2 of the inverter delay start relay KA correspond to the start / stop control signal input of the inverter and the ground terminal of the inverter, respectively; the two ends of the RP adjustable potentiometer are connected to the inverter's electrical signal output terminal and ground terminal, respectively, and the adjustable terminal of the RP adjustable potentiometer is connected to the inverter's drive signal input terminal; the series circuit formed by the inverter stop button, inverter start button, and the coil of the inverter delay start relay KA is connected between the 24V external DC power supply and ground, and the first normally open contact KA-1 of the inverter start / stop relay is connected in parallel to both ends of the inverter start button to form a self-locking circuit; The motor control circuit is divided into the main power supply circuit and the control circuit. The motor control circuit includes the circuit breaker QF, the main power supply contactor KM1, the thermal relay FR, the motor stop button SB1, the motor start button SB2, the main contactor KM1, the star contactor KM2, the angular contactor KM3, and the time relay KT; Main power supply circuit: The L1 phase line of the power supply output terminal of the inverter is connected to the L1 phase line input side contact of the circuit breaker QF, the L1 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the first normally open contact of the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the first normally open contact of the three normally open contacts of the main contactor KM1 is connected to the L1 phase line input side contact of the thermal relay FR, and the L1 phase line output side contact of the thermal relay FR is connected to the power supply input terminal U1 pin of the motor M; The L2 phase line of the power supply output terminal of the frequency converter is connected to the L2 phase line input side contact of the circuit breaker QF, the L2 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the second normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the second normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L2 phase line input side contact of the thermal relay FR, and the L2 phase line output side contact of the thermal relay FR is connected to the power supply input terminal V1 pin of the motor M; The L3 phase line of the power supply output terminal of the inverter is connected to the L3 phase line input side contact of the circuit breaker QF, the L3 phase line output side contact of the circuit breaker QF is connected to the electric energy signal input side contact of the third normally open contact among the three normally open contacts of the main contactor KM1, the electric energy signal output side contact of the third normally open contact among the three normally open contacts of the main contactor KM1 is connected to the L3 phase line input side contact of the thermal relay FR, and the L3 phase line output side contact of the thermal relay FR is connected to the power supply input terminal W1 pin of the motor M; The three normally open contacts of the angular contactor KM3 are connected in parallel with the motor M: the first normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal U1 pin of the motor M and the neutral line terminal U2 pin of the motor M, the second normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal V1 pin of the motor M and the neutral line terminal V2 pin of the motor M; the third normally open contact of the three normally open contacts of the angular contactor KM3 is connected between the power supply input terminal W1 pin of the motor M and the neutral line terminal W2 pin of the motor M; The neutral terminals U2, V2, and W2 of the motor M are connected in series with the first, second, and third normally open contacts of the three-pronged normally open contacts of the star contactor KM2, and the star is closed; The control circuit is connected between the L1 phase line of the power supply output terminal of the inverter and the ground neutral line N. The control circuit includes the main contactor control branch, the star contactor control branch, and the angular contactor control branch; The main contactor control branch includes a series circuit consisting of the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1, the normally open motor start button SB2, and the coil of the main contactor KM1, which are connected in series in sequence. The phase line L1 is connected to the power input side pin A2 of the normally closed contact of the thermal relay FR, and the power output side pin A1 of the coil of the main contactor KM1 is connected to the ground neutral line N. The single-pole normally open contact KM1-1 of the main contactor KM1 is connected in parallel with the start button SB2 to form a self-locking circuit. The star contactor control branch includes a series circuit formed by the normally closed contact KM3-2 of the angular contactor KM3, the normally closed contact of the time relay KT, and the coil of the star contactor KM2, connected in series in sequence. The power input pin of the normally closed contact KM3-2 of the angular contactor KM3 is connected to the power output pin of the start button SB2, and the power output pin A1 of the coil of the star contactor KM2 is connected to the grounded neutral line N. The two ends of the coil of the time relay KT are connected in parallel to the two ends of the series circuit formed by the normally closed contact of the time relay KT and the coil of the star contactor KM2. The angular contactor control branch includes a series circuit formed by connecting the normally closed contact KM2-1 of the star contactor KM2, the normally open contact of the time relay KT, and the coil of the angular contactor KM3 in series. The power input pin of the normally closed contact KM2-1 of the star contactor KM2 is connected to the power output pin of the start button SB2, and the power output pin A1 of the coil of the angular contactor KM3 is connected to the grounded neutral line N. The normally open contact KM3-1 of the angular contactor KM3 is connected in parallel with the normally open contact of the time relay KT to form a self-locking circuit. Press the inverter start button and the motor start button SB2 to turn on the inverter. The inverter's mains input terminal inputs 220V mains power, and the coil of the inverter's delayed start relay KA is energized. After the second normally open contact KA-2 of the inverter's delayed start relay KA is delayed and closed, the inverter's start / stop control signal input terminal DI1 is connected to the ground terminal. The inverter's start / stop control signal input terminal DI1 changes from high level to low level. The inverter receives the low level signal and controls the inverter's three-phase power supply output terminal to output three Phase power supply signal is supplied to the power supply input terminal of the motor control circuit, and the L1 phase line of the three-phase power supply output terminal of the inverter is energized. The electrical signal reaches the coil of the main contactor KM1 through the normally closed contact of the thermal relay FR, the normally closed motor stop button SB1, and the connected motor start button SB2. The first, second, and third normally open contacts of the three-way normally open contacts of the main contactor KM1 are closed at the same time, and the single normally open contact KM1-1 of the main contactor KM1 is closed, forming a self-locking circuit with the start button SB2; At the same time, the electrical signal reaches the coil of the star contactor KM2 through the closed normally closed contact KM3-2 of the angular contactor and the normally closed contact of the time relay KT. The coil of the star contactor KM2 is energized, the three-way normally open contact of the star contactor KM2 is closed, and the motor M enters the star starting state; at the same time, the electrical signal reaches the coil of the time relay KT through the closed normally closed contact KM3-2 of the angular contactor, and the time relay KT starts timing. The normally open contact of the time relay KT remains in the open state before the timing time expires, and the normally closed contact of the time relay K remains in the closed state before the timing time expires; when the timing of the time relay KT expires, the normally open contact of the time relay KT closes. When the motor starts, the electric signal reaches the coil of the angular contactor KM3 through the normally closed contact KM2-1 of the star contactor KM2 and the normally open contact of the time relay KT. The coil of the angular contactor KM3 is energized, and the normally open contact KM3-1 of the angular contactor KM3 is closed, forming a self-locking circuit. At the same time, the normally closed contact KM3-2 of the angular contactor KM3 is disconnected, the coil of the star contactor KT is de-energized, and the coil of the time relay KT is de-energized; at the same time, the normally closed contact KM3-2 of the angular contactor KM3 is disconnected, the coil of the star contactor KM2 is de-energized, and the three-way normally open contact of the star contactor KM2 is disconnected. The star start state of the motor M stops, and the motor M enters the angle start state.

2. The star-delta step-down starting circuit demonstration test bench according to claim 1, characterized in that: The fixing seat and the assembly display board are combined into a table, the table includes a storage table drawer, the assembly display board is a tabletop covering the table, and the assembly display board and the storage table drawer are movably connected.

3. The star-delta step-down starting circuit demonstration test bench according to claim 2, characterized in that: The storage table drawer includes a storage space that opens toward the sky.

4. The star-delta step-down starting circuit demonstration test bench according to claim 3, characterized in that: A through groove for installing and supporting the assembly display board is provided on one side of the storage table drawer, and the inner groove width of the through groove matches the thickness of the supported assembly display board.

5. The star-delta step-down starting circuit demonstration test bench according to claim 3, characterized in that: One side of the storage table drawer is connected to the assembly display board through a loose-leaf hinge.

6. The star-delta step-down starting circuit demonstration test bench according to claim 3, characterized in that: One side of the storage table drawer is connected to the assembly display board through a hinge.

7. The star-delta step-down starting circuit demonstration test bench according to claim 3, characterized in that: The storage table drawer and the assembly display board are connected through a pneumatic rod.

8. The star-delta step-down starting circuit demonstration test bench according to claim 2, characterized in that: The assembly display board is provided with a mounting hole matrix, which is mounting holes evenly arranged in the horizontal and vertical directions and is used for mounting and fixing electrical components.

9. The star-delta step-down starting circuit demonstration test bench according to claim 2, characterized in that: The assembly display board is provided with horizontal or vertical long strip hollow holes.

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