The reason analysis diagram of the alternating positive and negative rotation of the motor
The following is an explanation of the principle of alternating forward and backward rotation of the motor: ##I. Explanation of the principle analysis diagram based on the relay control circuit 1. * * Main circuit part ** - Main switch QF: It is the main switch of the main circuit and the control circuit, mainly used to isolate the power supply and short-circuit protection. - AC contactors KM1 and KM2 main contacts: connected in series in the main circuit, switched on and off to control the positive and negative rotation cycle of the motor. For example, when the KM1 main contact is closed, the motor receives a power input of a phase sequence and turns forward; when the KM2 main contact is closed, the motor receives a power input of a changed phase sequence and turns backward. 2. * * Control circuit part ** - "Relay KC: After pressing the start button, the KC coil is energized, and its normally open contact is closed and locked in the closed position. This is the start of the entire control circuit. - Time Relays KT1 and KT2: - When the KC normally open contact is closed, the KT1 and KM1 coil circuits are connected. The main contact of KM1 is closed to make the motor rotate forward, and the normally closed contact of KM1 is opened (in the coil circuit of KM2) to prevent the reversing contactors from getting electricity when the motor is rotating forward. KT1 was connected in series to the delay contacts of the KM1 and KM2 coil circuits, and the timer started. - When the KT1 delay contact reaches the set time, the delay break contact is opened to cause the KM1 coil to lose power (the main contact of the forward rotating contactors is opened), and the delay close contact is closed. At this time, the KM2 coil and the time relay KT2 coil are energized, the KM2 main contact is closed, and the motor is reversed. The KM2 normally closed contact is opened (in the KM1 coil circuit) to prevent short circuit. - Then, KT2 was connected in series with the time relay delay break contact of the KT1 coil circuit to start timing. When the KT2 delay break contact reached the set time, the KT1 coil lost power, and the two delay contacts of KT1 were reset. Then, the KM2 and KT1 coil lost power, and the KM2 main contact was disconnected. After the relevant contacts were reset, the AC contractor coil KM1 and the time relay KT1 coil were energized again, and so on. ##II. Explanation of the principle analysis diagram of the control system (ladder diagram) 1. * * Forward Rotation Control ** - Press the forward start button, SSB2 (in the ladder diagram, the corresponding X0 turns on), and its normally open contact is connected. The coil of Y0 is "energized" and self-protected, which makes the coil of KM1 energized and the motor starts to rotate forward. Here, the normally closed electric shocks of Y0 and Y1 were connected in series with each other's coil to form an interlocked loop, ensuring that the coil of KM1 and KM2 would not be energized at the same time. 2. * * Reverse Control ** - When the motor is rotating forward (Y0 is on), if you directly press the reverse start button SSB3 (X1 becomes on), the normally closed contact of X1 will be disconnected, causing the Y0 coil to "lose power". At the same time, the normally open contact of X1 will be connected, causing the Y1 coil to "gain power", and the motor will turn from forward to reverse. 3. * * Interlocking mechanism ** - In the ladder diagram, in addition to connecting the normally closed contact of Y0 and Y1 to the coil of the other party in series (called "electrical interlocked "), there was also a" button interlocked ". The normally closed contact of the reverse start button X1 was connected in series with the coil of Y0 that controlled the forward rotation, and the normally closed contact of the forward start button X0 was connected in series with the coil of Y1 that controlled the reverse rotation. This double interlocked ensured the safety and reliability of the forward and reverse rotation control. ##III. Explanation of the principle analysis diagram based on the double interlocked positive and negative rotation control circuit (double interlocked contactors and buttons) 1. * * Forward Rotation Start ** - Press the start button of the SSB1 forward rotation, and its break contact will first break the reverse circuit to realize the button interlocked, and then its contact will close, and the KM1 coil will be energized. The KM1 break-off auxiliary contact first breaks the reverse circuit to realize the mutual locking of the contactors, then the KM1 break-on auxiliary contact and the KM1 main contact are closed at the same time to realize the self-locking, and the motor is energized to rotate forward. 2. * * Reversal activated ** - Directly press the reverse start button of the SK2, and the break contact will first break the forward circuit to realize the button interlocked, and then the contact will be closed, and the KM2 coil will be energized. The KM2 movable break auxiliary contact first breaks the forward rotation circuit to realize the mutual locking of the contactors, then the KM2 movable close auxiliary contact and the KM2 main contact are closed at the same time to realize the self-locking, and the motor is energized to reverse. 3. * * Stop Operation ** - Press the stop button of the SSB3, and the motor will stop running. The double-interlocked circuit overcame the shortcoming that the stop button needed to be pressed when the positive and negative reversing control circuit of the interlocked contactors switched over. Read more exciting novels for free
What is the reason for the alternating positive and negative rotation of the motor?
What are the reasons for the alternating positive and negative rotation of the single-phase motor?
How to connect the positive and negative rotation of the motor with a timer?
Taking a three-phase motor as an example, a positive and negative rotation control circuit with a timer was as follows: First of all, there are contactors in the circuit. When the main contact of the KP contactors is closed, the motor will rotate forward. When the main contact of the KP contactors is closed, the motor will rotate in reverse. This is because changing the phase sequence of the three-phase motor will change the direction of the rotating magnetic field, which will cause the direction of the motor rotation to change. In this circuit, the timer played the role of controlling the forward and reverse switching time of the motor and the rest time. Take the power-on delay time relay as an example. Suppose you press the forward start button (such as sb2) first, kme will attract and self-lock to make the motor rotate forward. At this time, the timer kt1 will start to power-on and delay (for example, set five seconds). After five seconds, the contact of kt1 will move, open and close, making km2 attract (km1 release). The motor will switch to reverse direction. At the same time, km2 attracts and makes the kt2 coil receive electricity and start to delay (assuming it is also five seconds). After five seconds, the electric shock action of kt2 will be disconnected, km2 will release, and the motor will stop. Then, the timer kt1 was powered up again and delayed. After the time was up, km1 pulled the motor forward again, and so on. In the actual connection, attention should be paid to the connection order and interlocked relationship between the various components. For example, the positive and negative rotation interlocked to prevent the two contactors from short-circuit and other faults caused by the simultaneous attraction. At the same time, it was also necessary to consider the power transmission, self-locking, control logic and other factors of the circuit. However, this was only a basic principle of a motor with a timer. The actual application scenarios were different, and the circuit might be more complicated and required to follow electrical safety regulations for wire operation. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
the practical application of that delay positive and negative rotation of the motor
The delayed positive and negative rotation of the motor had applications in many practical scenarios: 1. ** Large washing machine **: It can use a positive and negative automatic controller to control the motor to achieve the positive and reverse functions. The reversing automatic controller was a double-pulse delay relay, suitable for control circuits with an AC of 50HZ and a rated voltage of 380V and below. It controlled the motor to rotate forward, stop, and reverse according to the predetermined time. There were two common models with a fixed stop time for forward and reverse rotation (such as 25 seconds for forward rotation, 5 seconds for stop, and 25 seconds for reverse rotation), and an variable stop time for forward and reverse rotation (forward rotation, reverse rotation, and stop can be set within 1 - 15 minutes). 2. ** Mechanical Equipment Control **: The delayed switching of the forward and reverse rotation of the motor is often used to control mechanical equipment. It can use the motor forward and reverse control module, which is composed of a power supply module, a control module, and a motor drive module. After connecting the power supply, the motor, and the control module and setting the parameters of the control module, the automatic switching of the positive and negative rotation of the motor and the delay control could be realized. It was also possible to use a single-chip computer to control the forward and reverse rotation of the motor. First, the motor drive module was connected to the single-chip computer controller, and then the control program was written. This could achieve more flexible control, and the control program could be designed according to needs. When switching between the positive and negative rotation of the motor, the following techniques should be paid attention to: - ** Setting of delay time **: Set it according to the equipment requirements, usually 1 - 5 seconds, to ensure the stability and safety of the equipment. - ** Selection of the motor drive module **: Consider the parameters such as the motor power and voltage to ensure the accuracy and stability of the motor's forward and reverse rotation control. At the same time, pay attention to the quality and reliability of the motor drive module to ensure the long-term stable operation of the equipment. - ** Controller's reliability and stability **: The controller is the core part, and its reliability and stability affect the operation and safety of the equipment. The quality and reliability should be taken into consideration when choosing, and it should be fully tested and verified. 3. ** Control of specific actions in the motor control **: For example, when controlling the stepping motor, press the start switch to trigger the cylinder to push out and maintain for a certain time (such as 2s), and then the motor will rotate forward. When it touches the sensor, it will slow down and stop. When the motor stops, it will trigger the cylinder to retract and maintain for a certain time (such as 3s), and then the motor will rotate backward. When it touches the sensor, it will stop urgently. This involved the use of multiple instructions, including adding wait for input instructions, triggering output instructions, delaying wait instructions, and so on. 4. ** Three-phase motor positive and negative transfer wire control **: The positive and negative transfer wire of the three-phase motor can control the positive and negative rotation of the motor by pressing the forward or reverse button, using the buttons, coil, and normally closed contacts in different circuits. During this process, a certain delay can be set through the relevant control circuit. 5. ** In some conventional control scenarios of the motor, such as using a delay relay to realize the functions of the motor's timed start, stop, and forward and backward rotation control. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Can a single-phase motor have positive and negative rotation?
Not all single-phase motor could achieve positive and negative rotation. For example, shaded pole motor, submerged pump motor, etc., due to their special use, although some of them had a capacity, they would be modified during use, such as adding one-way bearings, reversing sleeves, etc. These motor could not rotate forward and backward. In principle, double-capacity and single-capacity motor could achieve positive and negative rotation. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Using r instruction to program the control of the positive and negative rotation of the motor
The following is the general idea of programming the motor reverse rotation control based on the S (set) and R (reset) commands: ##I. I/O allocation 1. ** Entering Device ** - A stop button (such as I0.0) is required to stop the operation of the motor. - Forward rotation button (for example, I0.1). When this button is pressed, the motor will start in the forward direction. - Reverse button (e.g. I0.2), press this button to start the motor in reverse. 2. ** Outputting Device ** - Forward Contactor (e.g. Q0.1), used to control the opening and closing of the forward circuit of the motor. - Reverse Contactor (such as Q0.2), which controls the connection and interruption of the motor reverse circuit. ##2. Program logic 1. ** Forward Rotation Control Logics ** - When the Forward Rotation button (I0.1) is pressed, use the S command to set the Forward Rotation Contactor (Q0.1), and the motor starts to rotate forward. At the same time, in order to prevent the forward and reverse rotation from running at the same time, it was necessary to use interlocked logic. That is, when Q0.1 is set, the logic of the normally closed contact Q0.1 is inverted and then connected in series with the reversal control logic to ensure that the reversal contactors (Q0.2) cannot be energized. - When the stop button (I0.0) is pressed, use the R command to reset the forward rotating contactors (Q0.1), and the motor stops rotating forward. 2. ** Reverse control logic ** - When the reverse button (I0.2) is pressed, use the S command to set the reversing contactors (Q0.2), and the motor will reverse. Similarly, when Q0.2 is set, the logic of the normally closed contact Q0.2 is inverted and connected in series with the forward rotation control logic to prevent the forward rotation contactors (Q0.1) from being energized. - When the stop button (I0.0) is pressed, the reversing contactors (Q0.2) are reset through the R command, and the motor stops reversing. The following is a simple ladder diagram example (described in a programming style similar to the ladder diagram of a PC): ###(I) Forward Rotation |--I0.1 (Forward Turn button)--|S|--Q0.1 (Forward Contactor)--| |--Q0.1 (normally closed)--||--I0.2 (Reverse button)--|(Interlocking logic) |--I0.0 (stop button)--|R|--Q0.1 (Forward Contactor)--| ###(2) Reverse Part |--I0.2 (Reverse button)--|S|--Q0.2 (Reverse Contactor)--| |--Q0.2 (normally closed)--||--I0.1 (Forward Turn button)--|(Interlocking logic) |--I0.0 (stop button)--|R|--Q0.2 (Reverse Contactor)--| In this way, the positive and negative rotation control programming of the motor could be realized through the S and R instructions and the interlocked logic. In actual programming, it was also necessary to consider the protection mechanism of the motor, such as overload protection, and make appropriate adjustments according to the specific model of the PC and the programming environment. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to connect the 48-volts direct current motor to the positive and negative rotation
For a 48V shunt-excited direct current motor (the motor junction box has four terminal blocks, two excitations, and two armatures), as long as the switch is used to change the voltage of the armatures, the direction of the motor can be changed. The following methods could also be used: 1. If it was manually controlled, a mechanical switch could be used to realize the forward and reverse rotation of the motor. A double-pole double-throw switch could be used. The connection method was as follows: When the switch was turned up, the A pole of the direct current motor was connected to the true voltage of 48V, the B pole was connected to the ground voltage of 48V, and the motor was rotated forward (reverse). When the switch was turned down, the B pole of the direct current motor was connected to the true voltage of 48V, the A pole was connected to the ground voltage of 48V, and the motor was rotated backward (forward). 2. A two-way relay was used to realize the positive and negative rotation of the direct current motor. When the relay is not working, the A pole of the direct current motor is connected to Vac (48V), the B pole is connected to Ground, and the motor is rotating forward (reverse); when the relay is connected, the B pole of the direct current motor is connected to Vac (48V), the A pole is connected to Ground, and the motor is rotating backward (forward). 3. The positive and negative rotation circuit was formed by two relay (each relay had three contacts, normally open, normally closed and public, respectively. The action of each group of contacts was controlled by two groups of coil). The positive and negative rotation of the motor was realized by controlling the power supply and power failure of the two groups of coil: - When the two sets of coil are cut off, the motor is in a stopped state; - When the first group of coil is energized and the second group of coil is de-energized, the current loop is formed to make the motor rotate forward; - When the second group of coil is energized and the first group of coil is de-energized, the current loop is formed to cause the motor to rotate in reverse; - When both sets of coil were energized, the motor stopped. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How long does it take for the motor to switch between positive and negative rotation?
Whether or not the motor needed to switch between positive and negative rotation depended on the specific situation. If the inertia of the motor is relatively large, it is recommended to add a brake resistance; if it is a high-power servo-motor, it is necessary to add a brake unit and a brake resistance. It is best to let the motor stop before reversing the operation. For the motor that uses the H-bridge drive circuit, in order to avoid the circuit damage caused by the opening or closing of the upper and lower bridge arms at the same time, a " dead time " will be set. For example, when the motor is switched between positive and negative rotation, it must ensure that there is a transition time for the switching of the upper and lower bridge MOS tubes. In some control circuits, such as the control of the three-phase motor's positive and negative transfer line, the positive and negative switching can only be reversed after the stop button is pressed, and the direction cannot be changed during operation. Some control circuits adopt the double interlocked and delayed mode of the contactors and buttons. When the stop button or the reverse start button is pressed, the coil of the positive rotation contactors loses electricity, and the contactors reset. After a certain delay, the reverse rotation can be started. In the frequency changer, the " positive and negative dead time " setting range was from 0.1s to infinity. It was recommended to set it above 0.5s. If the setting was too short, the motor would be damaged. In addition, the shortest time for the motor to rotate from forward to reverse may be 0.2 seconds, which depends on the performance of the servos and the load inertia. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Circuit diagram of time control for forward and backward rotation of the motor
The following is a circuit diagram of a motor reverse rotation time control: As for the physical connection diagram, there was a problem with the control of the two AC contactors. The control requirement was to press the self-locking button SSS, and the motor would run clockwise (forward) for 35 seconds, counterclockwise (reverse) for 30 seconds, and then the motor would run forward for 35 seconds, and so on. Press the button SSS again, and the motor would stop running. A simple loop control circuit could be controlled by a relay. In the teaching materials, the symbol of an energized delay relay could be used to replace the double delay time relay, and a pulse counter (its function was the same as the double delay time relay) could also be used to replace the simulation. The double delay loop interlocked time relay used two independent time relay T1 and T2 to be interlocked to form a loop closing and opening working mode. The delay time of T1 and T2 was set independently. With the choice of time base, it could be set freely within a certain range. In a three-phase induction motor control system, KM1 and KM2 were AC contactors that controlled forward and reverse operation respectively. In the ladder diagram, two start-stop circuits were used to control the forward and reverse rotation of the motor. Pressing the start button for forward rotation, the corresponding input point X0 turned ON, and its normally open contact was connected. The coil of Y0 was "energized" and self-protected, so that the coil of KM1 was energized, and the motor began to rotate forward. Press the stop button, and X2 will turn ON, and its normally closed contact will be disconnected, causing the Y0 coil to "lose power" and the motor to stop running. In the ladder diagram, the normally closed contacts of Y0 and Y1 were connected in series with each other's coil (this was called "interlocked" in the relay circuit). At the same time, a "button interlocked" was also set, which was to connect the normally closed contact of the reverse start button X1 in series with the coil of Y0 that controlled the forward rotation, and connect the normally closed contact of the forward start button X0 in series with the coil of Y1 that controlled the reverse rotation. This setting can achieve positive and negative rotation control and ensure that the coil of KM1 and KM2 will not be energized at the same time. For the positive and negative transfer wires of the three-phase motor, press the forward rotation button circuit control button SP2, the KM1 coil, and the KM2 normally closed contact. The power is connected, and the forward rotation coil is energized to start the motor. At the same time, the normally closed contact of the KM1 is disconnected, and the KM2 coil connected in series cannot be connected. Press the reverse rotation button circuit control button SSB3, the KM2 coil, and the KM1 normally closed contact. The power is connected, and the reverse coil is energized to start the motor. At the same time, the normally open contact of the KM2 is disconnected, and the KM1 coil connected in series cannot be connected. These were part of the circuit diagram principles involved in the motor's forward and reverse rotation time control circuit. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is the reason for the reverse rotation of the variable frequency motor?
The reverse rotation of the variable frequency motor is usually caused by the following reasons: 1. ** Controller input signal ** - ** External signal interference **: The control signal of the variable frequency motor may be interfered by other external signals, resulting in the occurrence of positive and negative rotation. For example, strong electromagnetic interference in the surrounding environment may affect the normal transmission and identification of control signals, causing the motor to receive the wrong steering command. - ** Setting parameters error **: If there are errors in the setting parameters of the controller, such as the direction control and the starting method, the motor may have abnormal positive and reverse rotations. For example, if the forward direction parameters were mistakenly set to the reverse direction parameters, the motor would start in the wrong direction. 2. ** Mechanical structure ** - ** Mechanical brake failure **: If the mechanical brake fails to work normally, this mechanical structure failure will affect the normal operation of the motor, causing the motor to reverse. For example, the brake should be in a normal release state when the motor is started. If it fails and cannot be released, it may interfere with the normal rotation direction of the motor. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>