一拖一手動(dòng)旁路柜是由三個(gè)高壓隔離開(kāi)關(guān)QS1、QS2、QS3組成。手動(dòng)旁路柜嚴(yán)格按照“五防”聯(lián)鎖要求設(shè)計(jì)，變頻器輸出QS2和旁路高壓隔離開(kāi)關(guān)QS3機(jī)械閉鎖，完全能夠保證變頻調(diào)速系統(tǒng)安全運(yùn)行。
1)在變頻運(yùn)行狀況下，QS1、QS2閉合，QS3斷開(kāi)。
如需手動(dòng)切換至工頻運(yùn)行時(shí)，系統(tǒng)先停止變頻器輸出，斷開(kāi)用戶開(kāi)關(guān)，再由機(jī)械操作依次斷開(kāi)QS1、QS2，然后機(jī)械操作閉合QS3，使電機(jī)切換至工頻側(cè)，再合上用戶開(kāi)關(guān)，使電機(jī)工頻運(yùn)行；
2)在工頻旁路運(yùn)行狀況下，QS3閉合，QS1、QS2斷開(kāi)。
如需手動(dòng)切換至變頻運(yùn)行時(shí)，系統(tǒng)先斷開(kāi)用戶開(kāi)關(guān)，由機(jī)械操作斷開(kāi)QS3，然后由機(jī)械操作依次閉合QS2、QS1，使電機(jī)切換至變頻側(cè)，再合上用戶開(kāi)關(guān)。
2. 控制系統(tǒng)方案
為了更方便的操作，變頻器的起停在機(jī)旁箱進(jìn)行控制，在DCS上進(jìn)行監(jiān)控。頻率調(diào)節(jié)通過(guò)前級(jí)的傳感器返回的電流模擬量信號(hào)（4—20mA）進(jìn)行PID控制。其具體控制信號(hào)如下：
2.1 與高壓開(kāi)關(guān)柜聯(lián)鎖信號(hào)
1）合閘允許：常開(kāi)接點(diǎn)，閉合有效，此信號(hào)串聯(lián)在供電高壓開(kāi)關(guān)柜的合閘回路中，當(dāng)變頻器自檢完成或系統(tǒng)處于工頻狀態(tài)時(shí)，信號(hào)閉合，允許用戶合高壓電；
2）高壓跳閘：常閉接點(diǎn)，斷開(kāi)有效，此信號(hào)并聯(lián)在供電高壓開(kāi)關(guān)柜的分閘回路上，當(dāng)變頻器發(fā)生重大故障或急停信號(hào)有效時(shí)，分?jǐn)嘤脩舾邏弘姡?/p>
2.2 變頻器DO信號(hào)
以上輸出信號(hào)全部為獨(dú)立無(wú)源干接點(diǎn)，默認(rèn)為常開(kāi)接點(diǎn)，閉合有效，容量大小為250V AC 5A。
2.3 變頻器DI信號(hào)
以上輸入信號(hào)僅需客戶提供獨(dú)立無(wú)源干接點(diǎn)，脈沖信號(hào)，除急停外，其它信號(hào)均默認(rèn)為常開(kāi)接點(diǎn)，閉合有效；
2.4 變頻器AI信號(hào)
2.5 變頻器AO信號(hào)
四、現(xiàn)場(chǎng)實(shí)際運(yùn)行照片
現(xiàn)場(chǎng)變頻器運(yùn)行照片
現(xiàn)場(chǎng)電機(jī)照片
五、 改造后的效果：
1. 變頻調(diào)速的節(jié)能 steps
(1) Set the parameters and check whether the packaging film is installed and whether the color code photoelectric is intact.
(2) Press the manual button to test whether the packing bag is intact.
(3) Press the automatic button to randomly sample and measure whether it meets the requirements.
2.2 equipment process flow
According to the production requirements, the process is shown in Figure 2.1
3. Scheme determination
The program flow of pillow packaging machine looks very simple, but the internal calculation is very complicated. Now most domestic businesses in the industry are still using some single chip microcomputer or some low-cost PLC (Panasonic). Due to the increasingly fierce demand and competition of some foreign customers, they also began to upgrade the equipment function and brand. Siemens PLC entered the industry under this environment, At the beginning of the design, due to the consideration of price, Siemens S7-200 series PLC was selected at the initial stage. In the final debugging stage, it was found that the scanning cycle of PLC was more than 5 times larger than Panasonic PLC. Due to the use of the
