What is the main difference between motor reverse control and motor forward and reverse operation co

Reverse braking, of course, braking is the goal.

Forward and reverse is to change, and turning is the goal.

The common denominator is that both need to be commuted.

The differences, as mentioned above, are for different purposes.

In the forward and reverse control, there is a reverse braking process, and if the power is not interrupted after reverse braking, it becomes a positive and negative control.

The reverse control of the motor is relative to the forward control, for example, according to the U, V, W connection is forward rotation, then change one of the phases, such as: U, W, V, is the reversal.

As for motor rotation and reversal control, it means that two contactors are used in the main circuit.

Control KM1 and KM2, these two contactors are interlocked, that is, they are energized and contacted at different time periods, which changes the current direction of the motor, which also changes the steering of the motor. As for how to control the on/off of the two contactors at different times, there should be a control circuit, and the function of the control circuit is to control the on/off of the contactor in the main circuit.

To sum up, to put it simply, the forward or reverse rotation of the motor is actually realized in the main circuit; The rotation and reversal control of the motor is realized in the control circuit.

The wrong 2 wires of ABC are reversed, and I will send you a picture.

He's just a reversal, he can be reversed.

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.

There are three types of interlocking: pushbutton interlocking, contactor interlocking, and pushbutton and contactor composite interlocking (often called double interlocking). As shown in the figure, the first one is the contactor interlock, the second one is the double interlock, and the third one is the button interlock.

Contactor interlock.

Double interlocking. <>

Push button interlock.

<> the main circuit contactors KMI and KMZ are closed separately to complete the commutation and realize the forward and reverse rotation of the motor. KM1 and KM2 cannot be closed at the same time, otherwise, it will cause a two-phase short circuit in the main circuit. The circuit is overload protected by FR.

The control circuit control circuit is essentially composed of two start-up branches connected in parallel, but for the needs of production and safety, a restriction contact is added to each branch.

Asynchronous motor is a commonly used motor that is widely used in industry and life. Its forward and reverse control principle is mainly realized by changing the connection mode of the power cord of the Qiaoshan substation.

An asynchronous motor is usually constructed of three power lines, called "U phase", "V phase" and "W phase". When the power cord of the motor is connected to the power supply in the order of "U, V, W", the motor will rotate forward; If it is connected to the electric filial piety and the central source in the order of "W, V, U", the motor will be reversed.

The forward and reverse control principle of the motor is mainly realized by changing the connection of the power cord of the motor. The forward and reverse rotation control of the motor can also be achieved in other ways, such as through a variable frequency converter or an intelligent motor controller. But regardless of which method is adopted, the basic principle is achieved by changing the way the power cord of the motor is connected.