How to control the direction of the fan?The following are some ways to control the direction of the fan:
** 1. Relay-based control method (Positive and negative rotation and percentage control as an example)**
1. ** Relays Combined Logics **
- If a mode similar to positive and negative rotation and percentage control was used, such as positive and negative rotation channel 1, positive rotation associated relay 1, and reverse rotation associated relay 2, the system would be able to complete the control of the two relaying. When the forward rotation channel 1 is clicked to rotate forward, the relay 1 is pulled in and the relay 2 is disconnected; when the forward rotation channel 1 is clicked to rotate backward, the relay 2 is pulled in and the relay 1 is disconnected; when the forward rotation channel 1 is clicked to stop, the relay 1 is disconnected and the relay 2 is disconnected.
2. ** The application in specific devices (such as remote intelligent control devices of the Internet of Things)**
- In the scenario where the agricultural four-condition monitoring platform was added with the Internet of Things remote intelligent control device, the platform could realize the remote control of the on-site relay's switching value, forward and reverse rotation and percentage control, thus controlling the fan's forward and reverse rotation. For example, it could control all kinds of electric machines (including the electric machines related to the fans) on site to create good growth conditions for the plants in the greenhouse.
** 2. Controlled by a programmed logic controller **
1. ** System Construction **
- First of all, the control requirements of the system must be clear. For example, the three buttons were used to control the continuous forward rotation, reverse rotation, and stop of the motor (fan motor). It was also required to use a thermal relay to protect the motor from overload. In addition, it was required to control the forward and reverse rotation.
2. **I/O Device and Terminal Assignment **
- Confirm the input/output device and assign it the appropriate I/O terminal. For example, the buttons and thermal relay of the input device were connected to the corresponding input terminal of the PC, and the output terminal was connected to the contactors that controlled the forward and backward rotation of the fan.
3. ** Control circuit diagram and programming **
- Drawing the system control circuit diagram, and then writing the control program. Taking the programming software FXPG/WIN-C as an example, the ladder diagram control program was written.
- Forward Rotation Control Principle: When the external button of the input terminal corresponding to the forward rotation of the PC is pressed, the internal input relay corresponding to the terminal is energized, the normally open contact in the program is closed, and the output relay coil is energized. On the one hand, the normally open self-locking contact in the program is closed to lock the coil to supply power, and on the other hand, the normally closed contact is disconnected to prevent the reverse coil from being energized. The hard contact inside the output terminal is also closed, and the external forward rotation contactors are energized. The forward rotation contactors make the fan run in the forward direction.
- Reverse control principle: When the external button of the input terminal corresponding to reverse is pressed, the internal input relay corresponding to the terminal is energized, the normally open contact in the program is closed, and the reverse output relay coil is energized. Through similar self-locking, interlocked, and output contact closing actions, the reverse contactors coil is energized, and the fan runs in reverse.
- Stop control: When the stop button is pressed, the corresponding input relay will be energized, the normally closed contact in the program will be disconnected, the forward and reverse output relay coil will not be energized, and the corresponding contactors will lose power, and the fan will stop.
- Overload protection: When the motor (fan motor) is overloaded, the heating element of the thermal relay closes the normally open contact of the input terminal corresponding to the overload protection. The internal input relay corresponding to this terminal is energized, and the normally closed contact in the program is disconnected. The forward and reverse output relay coil cannot be energized, and the corresponding contactors lose power, and the fan stops.
** 3. Use fan reversing control equipment (specially designed equipment)**
1. ** Equipment composition and principle **
- This equipment includes a fan, a main circuit, and a control circuit. The main circuit includes a three-phase alternating current power supply, an isolating switch qs1, a main contact km1 - 1 of a forward rotating contactors km1 and a main contact km2 - 1 of a reverse rotating contactors km2; after the main contact km1 - 1 of the forward rotating contactors km1 and the main contact km2 - 1 of the reverse rotating contactors km2 are connected in parallel, one end of the main contact km1 - 1 is connected in series with the isolating switch qs1, and the other end of the main contact km2 - 1 is connected with a fan m, and the isolating switch qs1 is connected with the three-phase alternating current power supply.
2. ** Control circuit working process **
- The start-stop module includes isolating switch QS2 and other components, which are controlled by combination logic such as button switch and intermediate relay. For example, the intermediate relay Ka1 and the button switch Sb1, Sb2, etc. cooperate with each other. When the relevant button is pressed, the intermediate relay acts, and its normally open contact is closed, and the control module starts to work.
- The control module includes time relay kt1 and other components. Through the logical combination of the normally closed contacts of the forward rotating contactors km1 and the reverse rotating contactors km2, as well as the normally open and normally closed contacts of the time relay, the fan can switch between the forward and reverse rotating states. For example, when the forward rotating contactors km1 are energized, the wind turbine is rotating forward. According to the logic relationship in the control module, when reverse rotation is required, the reverse rotating contactors km2 are energized, and the wind turbine is rotating backward.
<a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>