The wiring method of the electromagnetic switch and the three phase asynchronous motor uses a voltag

Electromagnetic switch wiring method.

1. Generally, the three-phase contactor has a total of 8 points, three inputs, three outputs, and two control points. The output and input are corresponding, and it is easy to see. If you want to add self-locking, you also need to connect the wire from one of the terminals at the output point to the control point.

Once you know the principle, you should figure out the contacts of the external power supply, that is, the two contacts of the coil, which are generally at the lower part of the contactor, and on each side. The other inputs and outputs are generally in the upper part, and you can see it at a glance. Also pay attention to the voltage of the external power supply (220V or 380V), which is generally marked as yes.

And pay attention to whether the contact point is normally closed or normally open. If there is a self-locking control, it is enough to sort out the line according to the principle.

Principle: When the coil is energized, the static iron core generates electromagnetic attraction and engages the moving iron core. Since the contact system is linked with the moving iron, the moving iron core drives the three moving contacts to act at the same time, and the main contact is closed.

The auxiliary normally closed contact, which is mechanically connected to the main contact, is disconnected and the auxiliary normally open contact is closed, thus switching on the power supply. When the coil is de-energized, the suction disappears, and the linkage part of the moving core is separated by the reaction force of the spring, so that the main contact is disconnected, and the auxiliary normally closed contact mechanically connected to the main contact is closed, and the auxiliary normally open contact is disconnected, so as to cut off the power supply.

Wiring method of three-phase asynchronous motor.

The three-phase stator winding of the three-phase motor has two lead-out wires for each group of windings, one end is called the first end, and the other end is called the end. It is specified that the head end of the first phase winding is represented by d1. The ends are denoted by d4; The first end of the second phase winding is represented by d2, and the end is represented by d5; The first and last ends of the third phase winding are denoted by d3 and d6 respectively.

These six lead wires are introduced into the binding post of the junction box, and the binding post is marked with the mark of D1 D6 accordingly, and the six ends of the three-phase stator winding can be connected into a star (connected to 380V) or a triangle (connected to 220V).The star connection method is to connect the ends of the three-phase windings in parallel, that is, the three binding posts of D4, D5 and D6 are connected together with copper sheets, and the first end of the three-phase winding is connected to the three-phase AC power supply respectively, that is, D1, D2 and D3 are connected to the A, B, and C phases power supply respectively. The triangle connection method is to connect the first end of the first phase winding D1 with the end of the third phase winding D6, and then connect the one-phase power supply; The first end d2 of the second phase winding is connected with the end d4 of the first phase winding, and then connected to the two-phase power supply; The first end of the third phase winding D3 is connected with the end of the second phase winding D5, and then connected to the three-phase power supply.

That is, D1 and D6, D2 and D4, D3 and D5 are connected with copper sheets on the binding post, and then connected to the three-phase power supply respectively.

Three-phase asynchronous motor changed to single-phase operation

The power becomes the original 2 3 or below, and a starting capacitor may need to be added due to the high power).

Now it's the Y-line wiring method, just change it to the triangle wiring method.

The starting current of the AC asynchronous motor is 4 7 times the ratio of the starting current to the rated current, such a large starting current will cause the motor to heat up seriously, but the problem is not serious for a direct start, the current will be reduced quickly once the motor is started, although the starting current of the motor is very large, but it is too late to overheat the motor itself.

However, for frequently starting motors, the starting current must be considered. Control the starting torque of the motor, generally in times. The starting current is too small, the motor cannot be started with load, or the starting time is very long; If the starting torque is too large, the mechanical transmission mechanism will be affected and broken during starting.

Common starting methods: direct starting; Self-coupling transformer decompression start; y-δ buck start; Soft start, etc.

A three-phase AC asynchronous motor is an electric drag device that converts electrical energy into mechanical energy. It is mainly composed of a stator, a rotor, and an air gap between them.

After the stator windings are connected to the three-phase AC power supply, a rotating magnetic field is generated and the rotor is cut to obtain torque. Three-phase AC asynchronous motors have the advantages of simple structure, reliable operation, low cost, strong overload capacity and convenient use, installation and maintenance, and are widely used in various fields.

The three-phase asynchronous motor is mainly composed of a stator and a rotor, the stator is a stationary part, and the rotor is a rotating part, and there is a certain air gap between the stator and the rotor.

The stator is composed of three parts: core, winding and frame. The rotor is composed of a core and a winding, and the rotor winding is available in squirrel cage type and wire wound type. The squirrel cage rotor is composed of inserting copper strips into the rotor core groove, and then welding all the copper strips at both ends on two copper end rings; Like the stator winding, the wirewound rotor winding consists of a coil and is placed in the rotor core slot.

The starting current of the three-phase asynchronous motor is 4 to 7 times of the rated current, in order to limit the starting current, the step-down start and step-down start method are adopted: star-delta step-down start; Reactor step-down start-up, self-coupling step-down start-up, soft starter start-up, etc.

The rotor is affected by this torque and rotates in the direction of rotation of the rotating magnetic field. However, the rotational velocity n of the rotor is constant than the rotational velocity n0 of the rotating magnetic field, which is called the synchronous rotational speed, because if the two rotational speeds are equal.

There is no relative motion between the rotor and the rotating magnetic field, and the rotor conductor does not cut the magnetic flux, so it cannot generate induced electromotive force and current, and there is no electromagnetic torque, and the rotor will not continue to rotate. Therefore, the speed difference between the rotor and the rotating magnetic field is the main factor that guarantees the rotation of the rotor.

How it works:

The working principle of a three-phase asynchronous motor is based on the interaction of the stator rotating magnetic field (the resulting magnetic field generated by the three-phase current in the stator windings) and the rotor current ** the current in the sub-winding).

When the symmetrical three-phase winding of the stator is connected to the three-phase power supply, a symmetrical three-phase current will be introduced into the winding and a rotating magnetic field will be generated in space, which rotates in the circumferential direction of the stator.

When the magnetic field rotates, the conductor cutting magnetic flux of the rotor winding will produce an induced electromotive force e, and due to the presence of the electromotive force e, a rotor current i will be generated in the rotor winding. According to Ampere's law of electromagnetic force, the interaction of the rotor current with the rotating magnetic field will produce an electromagnetic force f (the direction of which is determined by the left-hand rule), which forms an electromagnetic torque on the axis of the rotor in the same direction as the rotation of the rotating magnetic field.

Why should a three-way AC motor be used for decompression starting? Because it does not decompress, the start-up current is too large, and it is easy to burn the circuit, and the commonly used is the new triangle step-down, well, free gas-added step-down start.

Fifth, why should the motor use the decompression line? There are several common ones, and there are several kinds.

The direct start of the three-phase AC asynchronous motor will produce a starting current of 6 8 times the rated current, which will affect the use of the power grid or other users, and will seriously burn the equipment. Therefore, the general step-down start mode is adjusted, and the common step-down start mode has star-delta start and auto-coupling step-down start, which reduces the start-up voltage by changing the winding wiring group and setting the coupler respectively, and reduces the start-up current. Safe and low maintenance.

1.Large starting current: Because the three-phase asynchronous motor needs to overcome the inertia force and friction of the rotor when starting, the starting current is large, and the field shortage is usually 5-7 times of the rated current.

2.Small torque: Due to the lower speed of the rotor at start-up, the torque is small, usually only 30-50% of the rated torque.

3.Long start-up time: Due to the high start-up current and small torque, the start-up time is long, usually taking from a few seconds to a few minutes.

4.During the start-up process, large electromagnetic noise and mechanical vibration will be generated, which will have a certain impact on the equipment and the surrounding environment.

In order to reduce the start-up current and start-up time, common methods include using a starter, reducing the supply voltage, increasing the rotor resistance, etc.

The low-voltage electrical appliances to be used and their functions are as follows:

1.The open circuit switch is responsible for the switching of the main power supply, and the overcurrent and short circuit protection of the main power supply.

2.AC contactor, responsible for the start and stop control of motor and high-current equipment.

3.The three-phase motor overcurrent protector prevents the motor from overcurrent or overcurrent due to lack of phase, and protects the motor.

4.Jog button switch, one red and one green, green is the start button, red is the stop button.

Three-phase AC asynchronous motor at the realization point. What voltages are needed for dynamic control?

There are two commonly used connection methods for three-phase AC asynchronous motors.

a.The star stool is connected to the shape of the moon and the moon.

b.The triangular connection method and the square tremor jointing method.

c.Triangular and star-shaped joints.

d.The sun is connected to the earth.

Correct answer: Triangle eggplant unformed and star-shaped.

What is the purpose of the wiring of the main circuit of the three-phase asynchronous motor, Hello Pro, the wiring of the main circuit of the three-phase asynchronous motor should achieve the purpose of the control circuit The identification of the three-phase AC asynchronous control circuit and the branch circuit of the installation circuit should generally be arranged vertically, so the electrical stuffy graphic symbols should also be drawn vertically, and the text symbols are generally placed horizontally. Sometimes, according to the needs of drawing, without changing the meaning of the symbol, both graphic and text symbols can be rotated, but not inverted. The static contact of the upper static and downward moving switch is on the upper side and is the power supply side; The moving contact is at the bottom, which is the load side.

If the electrical circuit needs to be drawn by the water worm Zhaoping, the electrical graphic symbol can be turned 90° counterclockwise from the vertical position, that is, the left is static and the right is moving. That is, the upper or left side is the power supply, and the lower or right side is the load. Left open, right closed Normally open contacts open to the left, while normally closed contacts close to the right.

If the electrical circuit needs to be drawn horizontally, the electrical graphic symbol can be turned 90° counterclockwise from the vertical position, that is, it is open and closed downward. How to draw the symbol of the contactor circuit a) Vertical drawing method b) Horizontal drawing method In the electrical schematic diagram, the coil and the contact are usually not drawn together, but drawn in different places of the circuit, but as long as they are marked with the same text symbol, it is the coil and contact of a device, for example, the same contactor coil, the main contact of the contactor and the auxiliary contact are represented by km1, when there is only one contactor in a circuit, the 1 in km1 is usually omitted I hope it can help you Oh, thank you! Have a great day!