Find the method of controlling the forward and reverse rotation of the motor, and how to realize the

This is very simple, as shown in the figure belowThe battery can also be connected in series in this way, and the motor is connected from the middle wire, and the switch k1 and k2 are connected from both ends of the battery packYou can control the single line to forward and reverse. See diagram below.

Scheme 1: Use the switch to directly control the forward and reverse rotation of the motor, this design is very simple and easy to understand, easy to repair and use.

Disadvantages: The scheme directly controls the spark arc, which will endanger the life safety of the operator. Set the SPDT switch to the left to start the motor to rotate forward, set the switch to the right end of the motor to start reversing, and set the switch to the middle position of the motor to stop rotating.

Scheme 2: Use electromagnetic relays to control the forward and reverse rotation of the motor. This design uses electromagnetic relays to make the control process safer and more reliable, which successfully solves the shortcomings of solution 1.

Disadvantages: The scheme cannot meet the basic requirements of modern life for automation and intelligence.

You turn on the positive and negative power lines of the DC motor, connect the positive (+) negative (-) under the A switch, connect the negative (-) positive (+) A under the B switch, and the positive (+) negative (-) pole on the B switch is unchanged.

··· Motor· ·

On · Off ·

b ·· Power supply · · switch a·

Represents the wire.

Boo knows what you're doing with this topic? It doesn't seem like it's possible to do it with these parts alone, especially with a single-pole switch, and the key can be used with a reverse 2 diode.

<>1. Single-phase motor.

Generally, it refers to a low-power single-phase asynchronous motor powered by a single-phase AC power supply. The single-phase motor has two coils, three heads, one end of the two coils is connected together as a head (common end), one head of the starting coil, one head of the running coil, the starting capacitor is connected between the running coil and the starting coil, the motor rotates when the power supply is connected to the common end and the running coil, and the motor reverses when the power supply is connected to the common end and the starting coil.

By changing the connection method of the capacitor with a switch or relay, the forward and reverse rotation of the single-phase motor can be realized.

2. For the forward and reverse rotation of the three-phase motor, only need to change the wiring position of any two of the three power cords of the three-phase motor.

The forward and reverse rotation of the motor is mainly achieved by replacing the two wires of the motor terminal. The specific steps are as follows:

First of all, disconnect the power supply, disassemble the motor junction box cover, you can see the three motor wiring, these three wires are the normal operation of the motor, respectively, corresponding to the ABC three-phase, from any exchange of two can change the motor rotation direction.

If it is a high-power motor, a contactor needs to be installed to control the forward and reverse rotation.

To put it simply, it is enough to change the phase sequence of the motor, and the three-phase motor can change the direction of any two power lines, and the other one does not move.

In order to realize forward and reverse rotation adjustment of the motor, any two of the phase sequence of its power supply can be adjusted (called commutation).

Usually the V phase is unchanged, and the U phase and W are relative to the regulator, in order to ensure that the two contactors are maintained.

The phase sequence of the motor can be reliably changed during operation, and the upper wiring of the contactor should be consistent when wiring, and the phase adjustment should be adjusted at the lower mouth of the contactor.

Due to the reversal of the two-phase phase sequence, it is necessary to ensure that the two km coils cannot be energized at the same time, otherwise a serious phase-to-phase short-circuit fault will occur, so interlocking must be adopted. For the sake of safety, the double interlocking forward and reverse control line of button interlocking (mechanical) and contactor interlocking (as shown in the figure below) is often used

With the use of button interlock, even if the forward and reverse buttons are pressed at the same time, the two contactors used for phase adjustment cannot be energized at the same time, and the phase-to-phase short circuit is mechanically avoided.

In addition, due to the interlocking of the contactor of the application, as long as one of the contactors hail Chang Hall is electrified, its long closed contact will not be closed, so that in the application of mechanical and electrical double interlocking, the power supply system of the motor can not be short-circuited between phases, which effectively protects the source-hidden motor, and also avoids accidents caused by interphase short circuits and burns out the contactors during phase adjustment.

The voltage between the L1 and L3 phases of the three-phase power supply is completely short-circuited by reversing the main contact of the electromagnetic contactor, so there will be a large short-circuit current.

flowed through, burned out the circuit.

Therefore, in order to prevent the short-circuit accident of the two-phase power supply, the main contacts of the contactor KM1 and KM2 are never allowed to close at the same time.

Three-phase asynchronous motor as shown in the picture above.

Electrical schematic diagram of forward and reverse rotation control of contactor interlocking.

In order to ensure that when one contactor is energized, the other contactor cannot be energized, so as to avoid the interphase short circuit of the fast and boring power supply, the normally closed auxiliary contact of the reverse contactor KM2 is connected in series in the forward rotation control circuit, and the normally closed auxiliary contact of the forward contactor KM1 is connected in series in the reverse control circuit.

When the contactor KM1 is energized, the normally closed contact of KM1 stringed in the reversal control circuit is broken, the reversal control circuit is cut off, and the main contact of KM2 cannot be closed when the main contact of KM1 is closed. Similarly, when the contactor KM2 is energized, the normally closed contact of KM2 is broken, cutting off the forward rotation control circuit, and reliably avoiding the occurrence of the two-phase power supply short circuit accident.

Dear, I am glad to answer for you: how to adjust the motor reversal to forward rotation only need to clear the phase sequence in the power supply, select two of the phases, and adjust them to complete the purpose of the motor reversal and forward rotation. In the process of adjustment, the V phase will not change, and the U phase and the W phase will be reversed.

In the process of the operation of the two contactors, in order to allow the phase sequence of the motor to be reversed, it is necessary to make the upper port of the contact equipment consistent when wiring, and then carry out phase adjustment work through the lower port of the contactor. In addition, since the phase sequence of the two phases needs to be replaced, the KM coil cannot be in the energized state to avoid failure. Thank you for your patience.

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