Taking the SIEMENS MM440 as an example, the circuit structure and working principle of the forward and reverse control circuit of the frequency changer are as follows: 1. ** Circuit components and functions ** - ** Button-related ** - BUB1 button: used to power up the frequency changer. - BUB2: It is used to cut off the power of the frequency changer. However, when it is running, this button will not work due to the blockage of the running relay KA1 or KA2. Pressing this button during running is ineffective. - BUB3: Control the motor to start in the forward direction. - [BUB4: Control the motor to start in reverse.] - BUB5: Realizing the motor stop function. - ** Relays ** - KA1 relay: responsible for forward rotation control. - KA2 relay: responsible for reverse rotation control. KA1 and KA2 are interlocked. The forward and reverse rotation cannot be directly switched. The engine must be stopped before changing the direction. - ** Others ** - When the protection function of the frequency changer is activated, the power supply can be quickly cut off through the KO Contactor, and it is convenient to realize self-locking and interlocked control. 2. ** Circuit Design Points ** - The main function of the KM contactors was to control the power supply of the frequency changer. The operation and stop of the frequency changer were not controlled by them. During operation, the power-off button SSB2 is blocked by the operation relay KA1 or KA2. Contactor KO can quickly cut off the power supply when the protection function of the frequency changer is activated, and it can also realize self-locking and interlocked control. - The control circuit is connected to the alarm output contacts 18 and 20 in series. When the frequency changer fails and alarms, the control circuit is cut off, and the KM is disconnected, thus causing the frequency changer to stop. - The main command button is used to turn on and off the frequency changer and to control the forward and reverse operation of the motor. 3. ** Forward and reverse control of the frequency changer ** - ** Forward Rotation ** - After pressing down on SSB1, the KM coil was energized, the main contact was connected, and the frequency changer was energized into standby mode. At the same time, the auxiliary normally open contact of the KM made the KM coil self-lock. When he pressed down on SSB3, the coil of KA1 was energized, and its normally open contact KA1 was connected to the DIN1 terminal of the frequency changer, and the motor began to rotate forward. The other normally open contact of the KA1 is closed to realize the self-locking of the KA1 coil. The normally closed contact is broken, and the KA2 coil cannot be energized. - ** Reversal ** - If you want to reverse the motor, you need to press the SSB5 to stop the motor. Then, he pressed down on SSB4, and the KA2 coil was energized. The normally open contact KA2 was closed, and the REV terminal of the frequency changer was connected. The motor rotated in reverse. At the same time, the other normally open contact of the KA2 is closed to cause the KA2 coil to self-lock. The normally closed contact KA2 is disconnected, and the KA1 coil cannot be energized. - ** Stop ** - When it is necessary to cut off the power, first press down on SSB5 to make the KA1 and KA2 coil lose power. The normally open contacts are cut off (the motor decelerates and stops), and the bypass power supply to SSB2 is removed. At this time, press down on SSB2, and the frequency changer will be cut off. When the fault alarm of the frequency changer was triggered, the control circuit was cut off, and the main circuit of the frequency changer was cut off. Read more exciting novels for free
There were three pronunciations for the word 'dan' which were dān, dān, and dān. - When reading dān, it was used as a verb to carry water with one's shoulder, and also to bear responsibility. - When reading dàn, it can mean a tool for carrying things (mostly made of bamboo and wood), such as "carrying pole"; it can also refer to a tool for carrying things (such as "carrying pole" and "bravely carrying heavy burden"). It is also used as a China market unit of weight (one load is equal to 100 jin). It can also be used as a measure word for things that are carried, such as "one load of water". - When reading dān, it was the same as "dān". The novel, Drunken Golden Cup, is equally exciting. Everyone is welcome to click and read it!
The price of professional photography services in Dongguan varies according to the type of photography, the level of service and the content of the service. For example, in terms of ID photo shooting, Fenggang Imprint Children's photography studio had a 1 yuan ID photo activity; offline portrait, Taobao still life, promotional video and other photography services, the price ranged from 100 yuan to 800 yuan per hour, such as Shu Shun 0r's service price was 100 yuan per hour, Iron Man Han Le's service price was 800 yuan per hour; In terms of wedding photography, the starting price of Wei Wei Bride in Dongguan was 3699 yuan, Milan International Wedding photography in Dongguan, Hollywood photography studio, Madam Jin wedding photography in Dongguan, and Dongguan Huayang photography studio were all 3999 yuan. There was also a one-price all-inclusive package customized by the director for 7799 yuan, and the amazing package of Madam Jin wedding photography in Dongguan was 7299 yuan. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
In the original novel, Luo Yining and Lu Jiaxue had been married for five years. There was no mention of the specific length of time the two of them spent together in the drama. The original novel of the TV series " The Unique Empress of Generals " was called " The Rebirth of the Poisonous Empress of Generals." The original plot was equally exciting. You can click on the link below to read the original novel.
Huo Yuhao had become handsome many times in the Peerless Tang Sect. Firstly, he had become handsome under the influence of the Snow Monarch's spirit soul. Secondly, Wang Qiu 'er's sacrifice had not only increased his strength, but also made him more handsome. In the anime, as the plot developed to the point where the Shrek Seven Monsters received the academy's reward, the officials released a new model. Huo Yuhao was now more handsome than before. His facial features were more pleasing to the eye, and his eyes were bright and filled with determination.
The following is an English translation of some sentences related to the National Day and rich in cultural meaning: - National Day is a great festival to celebrate the founding of the country. National Day is a great festival to celebrate the founding of the nation. - On National Day, people celebrate this special day with a deep love for their motherland. On National Day, people celebrate this special day with deep love for their motherland. - " The National Day military parade demonstrated the country's powerful military strength and national spirit. The military parade on National Day shows the powerful military strength and national spirit of the country. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The Netease Gaming Forum app was developed by Netease Games. It was a mobile application created for players. In this forum, players could exchange their gaming experiences, publish game guides, obtain the latest game information, and receive game gift packs. It gathered many game forums under Netease Games and had a built-in game gift pack center to provide players with a new mobile experience of reading posts, replying to posts, and posting. It also had functions such as customized content, selected hot posts, one-click check-in on the phone, and double points for replies.
There could be many reasons for a computer game's graphics to be stuck. If the screen was stuck, it could be a hardware or driver problem, or a CPU or heat dissipation problem. It could also be a software conflict or too much garbage. In terms of hardware, even if there was a standalone graphics card, if other hardware such as CPU performance was insufficient or memory was insufficient, it could cause the screen to be stuck. When the heat dissipation was not good, the hardware might automatically drop the frequency due to overheating, affecting performance and causing a stutter. In terms of drivers, if the graphics card driver was not installed correctly or the version was too old, the standalone display might not be able to play its proper performance and cause the screen to be stuck. In terms of software conflicts, some programs might interfere with each other, affecting the normal operation of the graphics card. Too many junk files might also occupy system resources and affect the smoothness of the game screen. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The price of Valentine's Day roses varies greatly due to many factors. On Valentine's Day in 2024, there were local red roses with a wholesale price of 2.5 yuan each. They could be sold at a retail price of 3 yuan after being packaged. Blue roses were sold at a wholesale price of 4 yuan each and could be sold at 5 yuan after being packaged. In terms of the price of the exquisite Valentine's Day bouquet, 99 red roses were 338 yuan, 9 red roses were 68 yuan, 11 red roses were 88 yuan, 21 red roses were 118 yuan, 33 red roses were 198 yuan, and 52 red roses were 268 yuan. At the same time, there were also cases where 99 roses cost nearly 2,000 yuan. There were also packaged red roses that cost 10 yuan per piece. The price of the bouquet varied from tens to hundreds of yuan depending on the flower material. In addition, during the Qixi Festival, the roses were unsalable. There was a situation where a bouquet of roses cost 3 yuan and no one was interested. The original work was equally exciting. You could click on the original work of " The Story of Rose " to understand the plot in advance!
Whether concert stars could accept gifts from fans varied. Some celebrities would accept gifts from their fans. For example, at some concerts, fans would send flowers and other gifts. The celebrities would accept them. However, there were also celebrities who refused to accept gifts from their fans in order to comply with the rules of the conference or to ensure that the performance went smoothly. For example, Eason Chan refused gifts from his fans in order to ensure that the next performance could be performed safely and successfully. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The following are some novels where the male protagonist likes the female protagonist from the beginning: - In " Young Master Mu Is Paranoid," the male lead had a ten-year-long crush on the female lead. - In " Green Plum, You're Not Good," the male lead had a crush on the female lead since he was young. - In " The White Moonlight Before My Eyes," Zhao Anzhi's crush on He Zesheng went through many stages. - "There will always be a secret love that will bloom." Zhang Anyi's secret love for Cheng Yi lasted for eight years. - In 'Pondering,' Qin Zhuo's secret love for Ji Qiu was hidden deep in his heart. - In " Eight Thousand Li Road," Chen Yue's crush on Meng Yun lasted for eight years. - In " City-Toppling Love," the male lead, Li Zeyan, was attracted to the female lead, Lin Wan 'er, the first time he saw her. - In " The Day I Saw You," the male lead, Lu Yi, was moved when he first saw the female lead, Gu Xiaoman. - In " Sweet Honey," the male lead Lei Yu fell in love with the female lead Su Xiao Tang at first sight. - In " The Tyrannical President Fell in Love with Me," the male lead, Shen Mohan, fell in love with the female lead, Qin Mengyao, at first sight. - In " Love Awakens," the male lead, Gu Beichen, fell in love with the female lead, Tang Xiaoxiao, at first sight. - In " Three Lives Three Lives Ten Miles Peach Blossom," the male lead Ye Hua fell in love with the female lead Bai Qian at first sight. - In " A Smile Is Alluring," the male lead, Xiao Nai, fell in love with the female lead, Bei Weiwei, at first sight. - In " Startling Step by Step," the male protagonist, Lord Fourth, fell in love with the female protagonist, Ruoxi, at first sight. - In " Silent Xiao Sheng," the male lead, He Yichen, fell in love with the female lead, Zhao Mosheng, at first sight. - In "Full Time Expert," the male lead, Ye Xiu, fell in love with the female lead, Su Mucheng, at first sight. - In " Southern Rain," the male lead, Shen Siyu, fell in love with the female lead, An Xun, at first sight. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>