What is the reason for the alternating 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>

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>

Most types of membrane type measuring pump do not have clear requirements for steering. Some types of pump may cause adverse effects on gears, turbine, and worm when reversing. There will also be noise and vibration during operation. It is recommended to confirm with the manufacturer whether there is a clear steering requirement. If there is no clear regulation, there is no need to consider the steering problem. However, there were also measuring pump's motor that could only rotate in the forward direction. If it was rotated in the reverse direction for a long time, it would damage the transmission mechanism. From the rear end of the motor, the rotation direction of the motor was clockwise. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

The reason for the forward and reverse rotation of the variable frequency motor is as follows: ** 1. Reason for Reversal ** 1. ** External signal interference ** - In the operating environment of the motor, if there are other external signals, these signals may interfere with the control signal of the variable frequency motor, causing the motor to reverse. For example, the presence of strong electromagnetic interference sources in the surroundings may affect the signal transmission that controls the motor's steering, causing the motor to receive the wrong steering command. 2. ** Setting parameters error ** - The parameters of the controller played a key role in the direction of the motor. If the direction control, starting method, and other parameters were not set correctly, the motor might reverse. For example, when setting the parameters related to the frequency changer, if the direction control parameters were set wrongly, the motor would rotate in the wrong direction when starting. 3. ** Mechanical structure problem ** - If the mechanical structure of the variable frequency motor malfunctioned, it would also cause reverse rotation. For example, when the mechanical brake failed to work properly, the normal operating state of the motor would be broken, and a reversal phenomenon might occur. This was because the mechanical brake was originally used to control the movement state of the motor. If it failed, the motor might not be controlled by the normal braking and starting direction. ** 2. Reason for positive rotation (from the perspective of normal operation)** 1. ** Correct setting of parameters ** - When the parameters of the controller, such as the output frequency of the frequency changer, direction control, etc., are accurately set according to the requirements of the normal forward rotation of the motor, the motor will rotate forward according to the set direction. This required an accurate understanding of the rated parameters of the motor (power, current, voltage, speed, maximum frequency, etc.) and the correct settings in the controller (such as the frequency changer). 2. ** No external interference and normal mechanical structure ** - In the absence of external signals interfering with the motor control signal, and the mechanical structure of the motor (including bearings, rotors, stators, etc.) is in normal working condition, the motor will operate in the pre-set forward direction. For example, if the various components in the mechanical structure cooperated well, there were no factors that hindered the normal forward rotation of the motor, and there was no external interference to change the direction of the motor's operation, the motor would rotate normally. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

The following are the practical steps of the AC contactors 'interlocked control: ** I. Preparing Work ** 1. Required electrical components: - Two AC contactors (KM1 and KM2). Choose the appropriate specifications according to the motor power. - Heat relay (KH), used for overload protection. - Circuit Breaker (QF), controls the switching of the circuit and provides short-circuit protection. - Start button (Forward Rotation SSB2, Reverse Rotation SSB3) and Stop button (SSB1). - Fuse (FO), for short-circuit protection. 2. Checking the electrical components: - Make sure that the contacts of the AC contactors are flexible and free from stagnation. - The setting value of the thermal relay was adjusted according to the rated current of the motor. - The normally open and normally closed contacts of the button were normal. ** 2. Circuit Connection (Main Circuit)** 1. Power connection: - The circuit breaker QF is connected from the three-phase power supply (L1, L2, L3). - When KM1 is working (forward rotation), the main circuit is connected in the order of L1 - L2 - L3, that is, the power supply supplies power to the motor M through QF, KM1 main contact and thermal relay KH, and the motor runs in the forward direction. - When the KM2 was working (reversing), the connection sequence became L1 - L3 - L2, and the order of L2 and L3 was exchanged through the KM2 to realize the motor reversal. 2. Connection to the motor: - The three-phase winding of the motor was connected to the output end of the thermal relay KH. ** 3. Circuit Connection (Control Circuit Part-Electric Interlock)** 1. First, connect to the public part: - Connecting a neutral wire to the thermal relay's normally closed terminal 95, then connecting a wire from the terminal 96 to the forward (km1) AC Contactor's terminal A2, and then connecting a wire from this terminal to the reverse (km2) AC Contactor's terminal A2. - From the live wire end, connect a wire to the fuse, and then connect a wire from the fuse to the stop button terminal 11 (normally closed for the STB3). 2. Forward Rotation Control Circuit Connection: - When the start button for forward rotation is pressed, the current passes through the thermal relay auxiliary contact KH1 - 2, 3, 4, 5 - 6, and reaches the KM1 coil to complete the start. KM1 pulled in, and at the same time, KM1 - 1 auxiliary contact closed to replace the pressing action of the SSB2 button, completing the self-locking. Moreover, the normally closed auxiliary contact of KM2 should be connected in series with the coil circuit of KM1. In this way, when KM2 is working (reversing), its normally closed contact will be disconnected to prevent KM1 from being accidentally energized. 3. Reverse Control Circuit Connection: - When the reverse start button SSB3 is pressed, the current passes through 1, 2, 3, 4, 9, and 10 to the KM2 coil to complete the reverse start. At the same time, the KM2 - 1 normally open contact is closed to achieve self-locking. At the same time, the normally closed auxiliary contact of KM1 is connected in series with the coil circuit of KM2. When KM1 is working (when it is rotating forward), its normally closed contact is disconnected to prevent KM2 from being powered up by mistake. ** 4. Inspection and Testing ** 1. Line inspection: - Check whether all the connecting wires are firm, loose or short-circuit. - Confirm that the electrical interlocked connection is correct, that is, the normally closed auxiliary contact of KM1 is connected in series in the coil circuit of KM2, and the normally closed auxiliary contact of KM2 is connected in series in the coil circuit of KM1. 2. No-load test: - Close the circuit breaker QF, press the forward start button SSB2, and observe whether the AC Contactor KM1 is pulled in and whether the motor is rotating forward. - Press the stop button, and the motor should stop rotating. - Press the reverse start button SSB3 and observe whether the AC Contactor KM2 is pulled in and whether the motor is reversed. 3. Load-testing (after ensuring that the no-load test is normal): - Connecting the motor load, repeating forward, reverse and stop operations, checking the operation of the motor under load, and paying attention to whether the thermal relay is working normally to prevent the motor from overloading. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

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>

There are several ways to detect the positive and negative rotation of a direct current motor: 1. ** Using sensors to detect **: install one or more Hall sensors or proximity switches on the outside of the direct current motor. When the direct current motor turns, the sensors will transmit the rotation information to the processor to determine the direction of the direct current motor. 2. ** Detection by voltage comparison **: By comparing the voltage at both ends of the motor, it can determine the positive and negative rotation of the motor. 3. ** Based on special circuit detection **: - A positive and negative reversal detection circuit is adopted. The circuit includes a first circuit and a second circuit, and the two circuits are respectively provided with a one-way conducting device. The two ends of the first circuit are connected with the two ends of the direct current motor. When the direct current motor is rotating forward, the one-way conducting device of the first circuit is conducted, and when the direct current motor is rotating backward and at rest, the one-way conducting device of the first circuit is cut off. The two ends of the second circuit are also connected with the two ends of the motor. When the direct current motor is rotating backward, the one-way conducting device of the second circuit is conducted, and when the direct current motor is rotating forward and at rest, the one-way conducting device of the second circuit is cut off. - Using a circuit structure similar to the H-bridge, the current circuit was changed by controlling the on-off of different switches in the circuit (such as the H-bridge circuit consisting of a MOS tube or a triode instead of a mechanical switch), so as to realize the forward and backward rotation of the motor. The forward and backward rotation state of the motor could be judged according to the control logic of the circuit and the current flow direction. 4. ** Mechanical structure detection device **: The device is provided with an upper support seat and a lower support seat, the lower support seat is provided with a rotating linked rotating shaft, the upper end of the linked rotating shaft is provided with a loading mechanism, the lower end of the linked rotating shaft is provided with a motor shaft fixing sleeve for fixing an output shaft of a motor to be tested, a stop mechanism is arranged near the linked rotating shaft and corresponds to the loading mechanism, a sensing mechanism is arranged at one end of the upper support seat and corresponds to the loading mechanism, a display seat is extended upwards from the upper support seat, and an indicator light group which is connected with the sensing mechanism is arranged on the display seat. The rotation direction of the load bearing mechanism was used to determine the forward and backward rotation of the motor, and the sensing mechanism and the indicator light group displayed the judgment result. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

The principle of single-phase motor reverse rotation is based on connecting a suitable capacity of the winding in series after starting the winding to produce a phase difference between the two winding. When the phase difference between the two winding was 90°, a magnetic field rotation would be generated. If this connection method was recorded as forward rotation, then the power line connected to the transformer would be swapped, and the motor would generate an opposite magnetic field, thus achieving reverse rotation. However, not all single-phase motor could be reversed. For example, shaded pole motor, submerged pump motor, etc., due to special use, they would be modified during use, adding one-way bearings, reversing sleeves, etc., but could not achieve forward and reverse rotation. In principle, double-capacity motor and single-capacity motor could achieve forward and reverse rotation. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

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