電路板sew

1. 妙語短篇B3電子版 急用 !!!

1.Step, Step, Roar
A little boy walked down the aisle at a wedding. As he made his way to the front, he would take two steps, then stop, and turn to the crowd, alternating between the bride』s side and the groom』s side. While facing the crowd, he would put his hands up like claws and roar. And so it went -- step, step, ROAR, step, step, ROAR -- all the way down the aisle.

As you can imagine, the crowd was near tears from laughing so hard by the time he reached the pulpit. The little boy, however, was getting more and more distressed from all the laughing, and he was near tears by the time he reached the pulpit.

When asked what he was doing, the child sniffed back his tears and said, 「 was being the ring bear.」

2.Step, Step, Roar
A little boy walked down the aisle at a wedding. As he made his way to the front, he would take two steps, then stop, and turn to the crowd, alternating between the bride』s side and the groom』s side. While facing the crowd, he would put his hands up like claws and roar. And so it went -- step, step, ROAR, step, step, ROAR -- all the way down the aisle.

As you can imagine, the crowd was near tears from laughing so hard by the time he reached the pulpit. The little boy, however, was getting more and more distressed from all the laughing, and he was near tears by the time he reached the pulpit.

When asked what he was doing, the child sniffed back his tears and said, 「I was being the ring bear.」
3.The Cat Lady
I have lived in my neighborhood for twenty years. It seems to me that I』ve spent at least ten of those years looking for a lost pet, either mine or one I』d seen listed in the newspaper』s lost-pet column.

Recently, I was at it again, going door-to-door looking for one of my own lost kitties, a little black cat named Nicholas who』d slipped out the door before I could stop him. I made my rounds, visiting with all the neighbors, describing Nicholas. Familiar with this routine, everyone promised to keep an eye out and call me if they spotted him.

Two blocks from my house, I noticed a gentleman raking leaves in the yard of a home that had recently been sold. I introced myself and presented my new neighbor with the plight of the missing Nicholas, asking if he had seen him.

「No,」 he replied, 「I』ve not seen a little black kitty around here.」 He thought for a moment, looked at me and said, 「But I know who you should ask. Several of my neighbors have told me that there』s a woman in the neighborhood who』s crazy about cats. They say she knows every cat around here, probably has dozens herself. They call her 『The Cat Lady.』 Be sure to check with her.」

「Oh, thank you,」 I said eagerly. 「Do you know where she lives?」

He pointed a finger down the street, 「It』s that one.」

I followed his finger and started to laugh.

He was pointing at my house!
4.She Told Me It Was Okay to Cry
I saw her last night for the first time in years. She was miserable. She had bleached her hair, trying to hide its true color, just as her rough front hid her deep unhappiness. She needed to talk, so we went for a walk. While I thought about my future, the college applications that had recently arrived, she thought about her past, the home she had recently left. Then she spoke. She told me about her love -- and I saw a dependent relationship with a dominating man. She told me about the drugs -- and I saw that they were her escape. She told me about her goals -- and I saw unrealistic material dreams. She told me she needed a friend -- and I saw hope, because at least I could give her that.

We had met in the second grade. She was missing a tooth, I was missing my friends. I had just moved across the continent to find cold metal swings and cold smirking faces outside the foreboding doors of P.S. 174, my new school. I asked her if I could see her Archie comic book, even though I didn』t really like comics; she said yes, even though she didn』t really like to share. Maybe we were both looking for a smile. And we found it. We found someone to giggle with late at night, someone to slurp hot chocolate with on the cold winter days when school was canceled and we would sit together by the bay window, watching the snow endlessly falling.

In the summer, at the pool, I got stung by a bee. She held my hand and told me that she was there and that it was okay to cry -- so I did. In the fall, we raked the leaves into piles and took turns jumping, never afraid because we knew that the multicolored bed would break our fall.

Only now, she had fallen and there was no one to catch her. We hadn』t spoken in months, we hadn』t seen each other in years. I had moved to California, she had moved out of the house. Our experiences were miles apart, making our hearts much father away from each other than the continent she had just traversed. Through her words I was alienated, but through her eyes I felt her yearning. She needed support in her search for strength and a new start. She needed my friendship now more than ever. So I took her hand and told her that I was there and that it was okay to cry -- so she did.
5.There Is an Oz
They arrive exactly at 8:00 a.m. to take her home, but she has been ready since before seven. She has taken a shower -- not an easy task lying down on a shower stretcher. She isn』t allowed to sit up yet without her body brace, but regardless, here she is, clean and freshly scrubbed and ever so anxious to go home. It has been two-and-a-half months since she has seen her home -- two-and-a-half months since the car accident. It doesn』t matter that she is going home in a wheelchair or that her legs don』t work. All she knows is that she is going home, and home will make everything okay. Even Dorothy says so: 「Oh, Auntie Em, there』s no place like home!」 It』s her favorite movie.

As they put her in the car, she thinks now of how much her father reminds her of the scarecrow in The Wizard of Oz. Like the scarecrow, he is built in pieces of many different things -- strength, courage and love. Especially love.

He isn』t an elegant man. Her father is tall and lanky and has dirt under his fingernails from working outside. He is strictly blue collar -- a laborer. He never went to college, didn』t even go to high school. By the world』s standards he isn』t 「ecated.」 An awful lot like the scarecrow -- but she knows differently. He doesn』t speak much, but when he does, she knows it is worth remembering. Even worth writing down. But she never has to write down anything that her father says because she knows she』ll never forget.

It is hard for her to sit comfortably while wearing the body brace and so she sits, still and unnatural, staring out the window. Her face is tense and tired and older somehow, much older than her seventeen years. She doesn』t even remember the world of a seventeen-year-old girl -- it』s as if that world never was. And she thinks she knows what Dorothy must have meant when she said, 「Oh, Toto, I don』t think we』re in Kansas anymore.」 It is more than an issue of geography, she is quite certain.

They pull out onto the road to begin their journey and approach the stop sign at the corner. The stop sign is just a formality; no one ever stops here. Today, however, is different. As he goes to coast through the intersection, she is instantly alert, the face alive and the eyes flashing. She grips the sides of the seat. 「Stop! That』s a stop sign! You could get us killed! Don』t you know that?」 And then, more quietly and with even more intensity, 「You don』t know what it』s like -- you have never been there.」 He looks at her and says nothing. The scarecrow and Dorothy journey onward.

As they continue to drive, her mind is constantly at work. She still hasn』t loosened her grip on the seat. She thinks of the eyes, the eyes that once belonged to her -- big, brown, soulful eyes that would sparkle with laugher at the slightest thought of happiness. Only the happiness is gone now and she doesn』t know where she left it or how to get it back. She only knows that it is gone and, in its absence, the sparkle has gone as well.

The eyes are not the same. They no longer reflect the soul of the person because that person no longer exists. The eyes now are deep and cold and empty -- pools of color that have been filled with something reaching far beyond the happiness that once was there. Like the yellow brick road it stretches endlessly, maddeningly, winding through valleys and woodlands, obscuring her vision until she has somehow lost sight of the Emerald City.

She lightly touches the tiny gold bracelet that she wears. It was a present from her mother and father, and she refuses to remove it from her wrist. It is engraved with her name on the side that is visible to others, but as in everything there are two sides, and only she knows the other is there. It is a single word engraved on the side of the bracelet that touches her skin and touches her heart: 「Hope.」 One small word that says so much about her life and what is now missing from it. She vaguely remembers hope -- what it felt like to hope for a college basketball scholarship or maybe a chance to dance professionally. Only now, she』s not sure she remembers hope as it was then -- a driving force, a fundamental part of her life. Now, hope is something that haunts her.

The dreams come nightly. Dreams of turning cartwheels in the yard or hitting a tennis ball against a brick wall. But there is one, the most vivid and recurring, and the most haunting of all...There is a lake and trees, a soft breeze and a perfect sky. It is a scene so beautiful it is almost beyond imagining. And in the midst of it all, she is walking. She has never felt more at peace.

But then she awakens and remembers. And remembering, she knows. She instinctively fingers the bracelet, the word. And the fear is almost overwhelming -- the fear of not knowing how to hope.

She thinks of her father』s God and how she now feels that God abandoned her. All at once, a single tear makes a trail down her thin, drawn face. Then another and another, and she is crying. 「Oh Daddy, they say I』ll never walk again! They』re the best and they say I』ll never walk. Daddy, what will I do?」

He looks at her now and he stops the car. This is the man who has been with her down every road, every trail and every path -- so very like the scarecrow. And he speaks. 「I know that they can put you back together. They can put steel rods in your back and sew you up. But look around you. Not one of your doctors can make a blade of grass.」

Suddenly she knows. He has taught her the most valuable lesson in her life and in all her journey: that she is never alone. There is an Oz; there is a wizard; there is a God. And there...is...hope. She releases her grip on the seat, looks out the window and smiles. And in that instant she loves her father more than she has ever loved him before
6.For the Best
It was two days after the tragic school shooting in Colorado, and I was feeling bad about what had happened to the students there. My school began having a lot of bomb threats and it seemed that police cars were there often. I was standing with my friend, Amberly, and her boyfriend when he casually said, 'I'm gonna blow up the school and kill everyone.' I asked, "Why would you want to do that?' and he said, 'I just do,' and walked away.

I was scared because no one had ever said anything like that to me before. I found out when talking to other friends that he also bragged about this to other people. My friends told me that I should tell an alt what he had said, but I was too scared and I made them promise not to tell anyone either.

One day, Amberly and I were talking about what he had said when the teacher overheard our conversation. She took me out into the hallway and made me tell her who had said it and what they had said. At first, I refused to say a word. She told me it really was for the best, so I told her. I felt awful for doing it. I was angry with her for making me tell who said it. I wasn't sure he really meant it and didn't want him to get into trouble.

He got suspended for two days and had two days of in- school detention after that. I sometimes wonder if I had not told, would he have done what he said he was going to do? The guys in Colorado seemed pretty normal to a lot of people. The bottom line is, you should never joke around about something as serious as killing people. If you do, responsible people have no choice but to have you checked out to ensure everyone else's safety.

After he was suspended, the whole sixth grade had an assembly. The principal and counselors told the students that there was a kid who was making threats and that he was suspended. I decided later to tell him that it was me who told on him so he wouldn't speculate about who did it. I was surprised to find that he was not angry with me for doing what I did. He was able to get help for his feel-ings and behavior.

Many people are in the same situation that I was in. If your friend is saying threatening stuff like my friend was, then they obviously need help-soon. It seems like when one school shooting happens, then another one occurs not too long after that. If there were any way that you could prevent one school shooting it could perhaps save your own life and many others as well. If I had to do it over again, I would-because it really was for the best
7.All Those Years
My friend Debbie』s two daughters were in high school when she experienced severe flu-like symptoms. Debbie visited her family doctor, who told her the flu bug had passed her by. Instead, she had been touched by the 「love bug」 and was now pregnant.

The birth of Tommy, a healthy, beautiful son, was an event for celebration, and as time went by, it seemed as though every day brought another reason to celebrate the gift of Tommy』s life. He was sweet, thoughtful, fun-loving and a joy to be around.

One day when Tommy was about five years old, he and Debbie were driving to the neighborhood mall. As is the way with children, out of nowhere, Tommy asked, 「Mom, how old were you when I was born?」

「Thirty-six, Tommy. Why?」 Debbie asked, wondering what his little mind was contemplating.

「What a shame!」 Tommy responded.

「What do you mean?」 Debbie inquired, more than a little puzzled. Looking at her with love-filled eyes, Tommy said, 「Just think of all those years we didn』t know each other.
8.Old People
At age ninety-two, Grandma Fritz still lived in her old two-story farmhouse, made homemade noodles, and did her laundry in her wringer-washer in the basement. She maintained her vegetable garden, big enough to feed all of Benton County, with just a hoe and spade. Her seventy-year-old children lovingly protested when she insisted on mowing her huge lawn with her ancient push mower.

「I only work outside in the cool, early mornings and in the evenings,」 Grandma explained, 「and I always wear my sunbonnet.」

Still, her children were understandably relieved when they heard she was attending the noon lunches at the local senior citizens' center.

Yes, Grandma admitted, as her daughter nodded approvingly. 「I cook for them. Those old people appreciate it so much!」
9.Albert
Working in a hospital with recent stroke patients was an all-or-nothing proposition. They were usually go grateful to be alive or just wanted to die. A quick glance told all.

Albert taught me much about strokes.

One afternoon while making rounds I'd met him, curled in a fetal position. A pale, dried-up old man with a look of death, head half-buried under a blanket. He didn't budge when I introced myself, and he said nothing when I referred to dinner 「soon.」

At the nurse's station, an attendant provided some history. He had no one. He'd lived too long. Wife of thirty years dead, five sons gone.

Well, maybe I could help. A chunky but pretty divorced nurse avoiding the male population outside of work, I could satisfy a need. I flirted.

The next day I wore a dress, not my usual nursing uniform but white. No lights on. Curtains drawn.

Albert hollered at the staff to get out. I pulled a chair close to his bed, crossing my shapely legs, head tilted. I gave him a perfect smile.

「Leave me. I want to die.」

「What a crime, all us single women out there.」

He looked annoyed. I rambled on about how I liked working 「rehab」 unit because I got to watch people reach their maximum potential. It was a place of possibilities. He said nothing.

Two days later ring shift report, I learned that Albert had asked when I'd be 「on.」 The charge nurse referred to him as my 「boyfriend」 and word got around. I never argued. Outside his room, I'd tell others not to bother 「my Albert.」

Soon he agreed to 「dangle,」 sit on the side of the bed to build up sitting tolerance, energy and balance. He agreed to 「work」 with physical therapy if I'd return 「to talk.」

Two months later, Albert was on a walker. By the third month, he'd progressed to a cane. Fridays we celebrated discharges with a barbecue. Albert and I danced to Edith Piaf. He wasn't graceful, but he was leading. Tear-streaked cheeks touched as we bade our good-byes.

Periodically roses, mums and sweet peas would turn up. He was gardening again.

Then one afternoon, a lovely lavender-clad woman came on the unit demanding 「that hussy.」

My supervisor called; I was in the middle of giving a bed bath.

「So you're the one! The woman who reminded my Albert that he's a man!」 Her head tilted in full smile as she handed me a wedding invitation.
10.For the Record
Less than a year after my wife』s funeral I was confronted with the most terrible realities of being a widower with five children.

Notes from school.

Field-trip permission slips, PTA election ballots, Troll Book order forms, sports sign-ups, medical forms and innumerable academic progress reports -- an onslaught of paperwork courtesy of the ecational bureaucracy.

This 「literature」 has to be read and signed, or placed at the bottom of the birdcage. Regardless of its destination it must be dealt with on a daily basis.

One day, eight-year-old Rachel was helping me complete five (count 』em, five) emergency treatment forms for school. She would fill in the generic information (name, address, phone number), and I would add the rest (insurance numbers, doctor』s name, date, signature). After signing the forms, I checked them for accuracy. It was then that I noticed on each card, in the slot beside Mother』s Business Phone, Rachel had written 「1-800-HEAVEN."

2. SEW-ML3PSF110是那種類型的減速機，能不能給個電子版的圖紙，QQ郵箱[email protected]

ML 斜齒輪減速機
3 3級傳動
P 平行軸
S 實心軸
F 底腳安裝
110 機座號
樓主給你一個樣本中得尺寸圖，已經發到你的郵箱中，請查收！

3. 焊接方法有哪些

焊接或稱熔接、鎔接，是一種以加熱或加壓方式接合金屬或其他熱塑性材料如塑料的製造工藝及技術。
金屬焊接方法有釺焊，熔焊、壓焊三大類。
釺焊是採用比母材熔點低的金屬材料作釺料，將焊件和釺料加熱到高於釺料熔點，低於母材熔化溫度，利用液態釺料潤濕母材，填充接頭間隙並與母材相互擴散實現連接焊件的方法。釺焊變形小，接頭光滑美觀，適合於焊接精密、復雜和由不同材料組成的構件，如蜂窩結構板、透平葉片、硬質合金刀具和印刷電路板等。釺焊前對工件必須進行細致加工和嚴格清洗，除去油污和過厚的氧化膜，保證介面裝配間隙。間隙一般要求在 0.01～0.1毫米之間。較之熔焊，釺焊時母材不熔化，僅釺料熔化；較之壓焊，釺焊時不對焊件施加壓力。釺焊形成的焊縫稱為釺縫。釺焊所用的填充金屬稱為釺料。
熔焊是在焊接過程中將工件介面加熱至熔化狀態，不加壓力完成焊接的方法。熔焊時，熱源將待焊兩工件介面處迅速加熱熔化，形成熔池。熔池隨熱源向前移動，冷卻後形成連續焊縫而將兩工件連接成為一體。
在熔焊過程中，如果大氣與高溫的熔池直接接觸，大氣中的氧就會氧化金屬和各種合金元素。大氣中的氮、水蒸汽等進入熔池，還會在隨後冷卻過程中在焊縫中形成氣孔、夾渣、裂紋等缺陷，惡化焊縫的質量和性能。
壓焊是在加壓條件下，使兩工件在固態下實現原子間結合，又稱固態焊接。常用的壓焊工藝是電阻對焊，當電流通過兩工件的連接端時，該處因電阻很大而溫度上升，當加熱至塑性狀態時，在軸向壓力作用下連接成為一體。

具體方法包括氣焊，電（弧）焊，壓焊，電渣焊，電阻焊，氣體保護焊，埋弧焊，閃光焊，冷焊等等。

4. 新手問題，SEW變頻器的問題，在線求教。

SEW變頻器的冷卻問題的解決方法
SEW變頻器的效率一般都可達到96-98%左右，但由於設備功率在正常內情況下容工作時，會產生大量的熱量；為保證設備的正常工作，如何把大量的熱量散發出去，優化散熱與通風方案，進行合理的設計與計算，實現設備的散熱，對於提高設備的可靠性顯得十分重要。
目前，SEW變頻器正常工作情況下的變頻器設備大約有3.5-4％的功率損耗主要以熱量形式散失在運行環境當中，其中電力電子器件的損耗約佔一般左右，如果不能及時有效的解決變頻器室的工作環境溫度問題，將直接危及變頻器本體的運行安全；zui終因為溫度過高，導致變頻器過熱保護動作跳閘；為保證變頻器具有良好的運行環境，必須對變頻器及運行環境的溫度控制採取響應的措施。

5. sew的伺服控制器常見報警代碼

故障原因：在IPOSplus運行方式下限位開關起動

解決辦法

1、檢查運行范圍

2、校正用戶程序

限位開關廣泛用於各類機床和起重機械，用以控制其行程、進行終端限位保護。在電梯的控制電路中，還利用行程開關來控制開關轎門的速度、自動開關門的限位，轎廂的上、下限位保護。

在實際生產中，將限位開關安裝在預先安排的位置，當裝於生產機械運動部件上的模塊撞擊行程開關時，限位開關的觸點動作，實現電路的切換。因此，行程開關是一種根據運動部件的行程位置而切換電路的電器，它的作用原理與按鈕類似。

(5)電路板sew擴展閱讀：

其他故障

伺服電機在有脈沖輸出時不運轉

a、監視控制器的脈沖輸出當前值以及脈沖輸出燈是否閃爍，確認指令脈沖已經執行並已經正常輸出脈沖；

b、檢查控制器到驅動器的控制電纜，動力電纜，編碼器電纜是否配線錯誤，破損或者接觸不良；

c、檢查帶制動器的伺服電機其制動器是否已經打開；監視伺服驅動器的面板確認脈沖指令是否輸入；

d、Run運行指令正常；

e、控制模式務必選擇位置控制模式；

f、伺服驅動器設置的輸入脈沖類型和指令脈沖的設置是否一致；

c、確保正轉側驅動禁止，反轉側驅動禁止信號以及偏差計數器復位信號沒有被輸入，脫開負載並且空載運行正常，檢查機械繫統。

6. 常見伺服驅動器有那些

三菱安川，台達匯川，西門子，發那科，東元，施耐德，歐姆龍，路斯特，科比，SEW，松下等等，品牌太多了。

7. 變頻器維修

1 變頻器的故障排除及維修

IGBT變頻調速器，自研製開發投入市場以來，以其優越的調速性能，可觀的節能量已為廣大的電機用戶所接受，正以每年大規模的銷售量走向社會，為電力、建材、石油、化工、煤礦等各行業的發展提供了優質的服務，其用戶群已遍布生產的各行各業，成為廣大用戶所喜愛的產品。
這里筆者結合自己在長期的售後服務工作中經歷的一些常見故障及處理方法，提出來與廣大的用戶及維修工作者進行探討，以期把該產品使用得更好，更切實的為顧客服務。

2 變頻器運行中有故障代碼顯示的故障

在變頻器的使用說明書中，有一欄具體闡述了變頻器有故障代碼顯示的故障，具體如表1所示。
注:表1中Io、Vo分別是輸出額定電流、輸入額定電壓;Vin是輸入電壓。
現就這幾種情況作一下分析。

表1 故障代碼顯示的故障

2.1 短路保護
若變頻器運行當中出現短路保護，停機後顯示「0」，說明是變頻器內部或外部出現了短路因素。這有以下幾方面的原因:

(1) 負載出現短路
這種情況下如果把負載甩開，即將變頻器與負載斷開，空開變頻器，變頻器應工作正常。這時我們用兆歐表(或稱搖表)測量一下電機絕緣，電機繞組將對地短路，或電機線及接線端子板絕緣變差，此時應檢查電機及附屬設施。

(2) 變頻器內部問題
如果上述檢測後負載無問題，變頻器空開仍出現短路保護，這是變頻器內部出現問題，應予以排除。如圖1所示。

圖1 變頻器主電路示意圖

在逆變橋的模塊當中，若IGBT的某一個結擊穿，都會形成短路保護，嚴重的可使橋臂擊穿，甚至於送不上電，前面的斷路器將跳閘。這種情況一般只允許再送一次電，以免故障擴大，造成更大的損失，應聯系廠家進行維修。

(3) 變頻器內部干擾或檢測電路有問題
有些機子內部干擾也易造成此類問題，此時變頻器並無太大的問題，只是不間斷的、無規律的出現短路保護，即所謂的誤保護，這就是干擾造成的。

變頻器的短路保護一般是從主迴路的正負母線上分流取樣，用電流感測器經主控板的檢測傳至主控晶元進行保護的，因此這些環節上任何一處出現問題，都可能造成故障停機。

對於干擾問題，現低壓大功率的及中高壓變頻器都加了光電隔離，但也有出現干擾的，主要是電流感測器的控制線走線不合理，可將該線單獨走線，遠離電源線、強電壓、大電流線及其他電磁輻射較強的線，或採用屏蔽線，以增強抗干擾能力，避免出現誤保護。

對於檢測電路出現的問題，一般是電流感測器、取樣電阻或檢測的門電路問題。電流感測器應用示波器檢測，其正常波形應如圖2所示。

圖2 電流感測器波形圖若波形不好或出現雜亂波形甚至於無波形，即說明電流感測器有問題，可更換一隻新的。對取樣電阻問題，有的機子使用時間長了，其阻值會變大，甚至於斷路，用萬用表可檢測出來，應予以更換成原來的阻值的或少小一些的電阻。

對於檢測的門電路，應檢查在靜態時的工作點，若狀態不對應更換之。

(4) 參數設置問題
對於提升機類或其他(如拉絲機、潛油電泵等)重負荷負載，需要設置低頻補償。若低頻補償設置不合理，也容易出現短路保護。一般以低頻下能啟動負載為宜，且越小越好，若太高了，不但會引起短路保護，還會使啟動後整個運行過程電流過大，引起相關的故障，如IGBT柵極燒斷，變頻器溫升高等。因此應逐漸加補償，使負荷剛能正常啟動為最佳。如圖3所示，V1為啟動電壓，V0為額定輸出電壓。

圖3 啟動過程的電壓曲線

(5) 在多單元並聯的變頻器中，若某一單元出現問題。勢必使其他單元承擔的電流大，造成單元間的電流不平衡，而出現過流或短路保護。因此對於多單元並聯的變頻器，應首先測其均流情況，發現異常應查找原因，排除故障。各單元的均流系數應不大於5%。

2.2 過流保護
變頻器出現過流保護，代碼顯示「1」，一般是由於負載過大引起，即負載電流超過額定電流的1.5倍即故障停機而保護。這一般對變頻器危害不大，但長期的過負荷容易引起變頻器內部溫升高，元器件老化或其他相應的故障。

圖4 感測器的波形圖

這種保護也有因變頻器內部故障引起的，若負載正常，變頻器仍出現過流保護，一般是檢測電路所引起，類似於短路故障的排除，如電流感測器、取樣電阻或檢測電路等。該處感測器波形如圖4所示，其包絡類似於正弦波，若波形不對或無波形，即為感測器損壞，應更換之。

過流保護用的檢測電路是模擬運放電路，如圖5所示。

圖5 過流檢測電路

在靜態下，測A點的工作電壓應為2.4V，若電壓不對即為該電路有問題，應查找原因予以排除。R4為取樣電阻，若有問題也應更換之。
過流保護的另一個原因就是缺相。當變頻器輸入缺相時，勢必引起母線電壓降低，負載電流加大，引起保護。而當變頻器輸出端缺相時，勢必使電機的另外兩相電流加大而引起過流保護。所以對輸入及輸出都應進行檢查，排除故障。

2.3 過、欠壓保護
變頻器出現過、欠壓保護，大多是由於電網的波動引起的，在變頻器的供電迴路中，若存在大負荷電機的直接啟動或停車，引起電網瞬間的大范圍波動即會引起變頻器過、欠壓保護，而不能正常工作。這種情況一般不會持續太久，電網波動過後即可正常運行。這種情況的改善只有增大供電變壓器容量，改善電網質量才能避免。

當電網工作正常時，即在允許波動范圍(380V±20%)內時，若變頻器仍出現這種保護，這就是變頻器內部的檢測電路出現故障了。一般過、欠壓保護的檢測電路如圖6所示。

圖6 過、欠壓保護的檢測電路

當W1調節不當時，即會使過、欠壓保護范圍變窄，出現誤保護。此時可適當調節電位器，一般在網電380V時，使變頻器面板顯示值(運行中按住「〈」鍵〉與實際值相符即可。當檢測迴路損壞時，如圖中的整流橋、濾波電容或R1、W1及R2中任一器件出現問題，也會使該電路工作不正常而失控。如有的機子R1損壞造成開路，使該電路P點得不到電壓，晶元即認為該處檢測不對而出現欠壓保護。P點的工作點范圍為1.9~2.1V，即對應其電壓波動范圍。

對於提升機變頻器，因回饋電網污染，增加了隔離電路，如圖7所示。

圖7 提升機變頻器過、欠壓保護的檢測電路

有時調節不當也會出現誤保護，此時應根據電網的波動仔細調節。因提升機負載在運行中電網是波動的，在提升重物時，電壓下降(有的可降20V)，在下放時回饋電網電壓升高，可根據這種變化進行調節，一般是增大W3，減小W2，直至在穩態下適合為止。
2.4 溫升過高保護
變頻器的溫升過高保護(面板顯示「5」)，一般是由於變頻器工作環境溫度太高引起的，此時應改善工作環境，增大周圍的空氣流動，使其在規定的溫度范圍內工作。
再一個原因就是變頻器本身散熱風道通風不暢造成的，有的工作環境惡劣，灰塵、粉塵太多，造成散熱風道堵塞而使風機抽不進冷風，因此用戶應對變頻器內部經常進行清理(一般每周一次)。也有的因風機質量差運轉過程中損壞，此時應更換風機。
還有一種情況就是在大功率的變頻器(尤其是多單元或中高壓變頻器)中，因溫度感測器走線太長，靠近主電路或電磁感應較強的地方，造成干擾，此時應採取抗干擾措施。如採用繼電器隔離，或加濾波電容等。如圖8所示。

圖8 溫升過高保護的抗干擾措施

2.5 電磁干擾太強
這種情況變頻器停機後不顯示故障代碼，只有小數點亮。這是一種比較難處理的故障。包括停機後顯示錯誤，如亂顯示，或運行中突然死機，頻率顯示正常而無輸出，都是因變頻器內外電磁干擾太強造成的。

這種故障的排除除了外界因素，將變頻器遠離強輻射的干擾源外，主要是應增強其自身的抗干擾能力。特別對於主控板，除了採取必要的屏蔽措施外，採取對外界隔離的方式尤為重要。
首先應盡量使主控板與外界的介面採用隔離措施。我們在高中壓及低壓大功率變頻器及提升機變頻器中採用了光纖傳輸隔離，在外界取樣電路(包括短路保護、過流保護、溫升保護及過、欠壓保護)中採用了光電隔離，在提升機與外界介面電路中採用了PLC隔離，這些措施都有效避免了外界的電磁干擾，在實踐應用中都得到了較好的效果。
再一點就是對變頻器的控制電路(主控板、分信號板及顯示板)中應用的數字電路，如74HC14、74HC00、74HC373及晶元89C51、87C196等，應特別強調每個集成塊都應加退耦電容，即如圖9所示。

圖9 集成電路的退耦電容

每個集成塊的電源腳對控制地都應加10μF/50V的電解電容並接103(0.01μF)的瓷片電容，以減小電源走線的干擾。對於晶元，電源與控制地之間應加電解電容10μF /50V並接105(1μF)的獨石電容，效果會更好些。筆者曾對一些干擾嚴重的機型進行過以上處理，效果較好。
對這類故障應逐漸積累經驗，不斷尋求解決途徑。有些機子使用時間太久，線路板上的濾波電容容量不夠造成濾波效果差，造成變頻器死機或失控，這種情況不太好處理，可更換一塊新線路板，一般可解決問題。

3 變頻器的其他故障

除以上有變頻器故障代碼顯示的故障外，變頻器還有一些非顯示的故障，現分析如下，供大家參考。

3.1 主迴路跳閘
這種故障表現為變頻器運行過程中有大的響聲(俗稱「放炮」)，或開機時送不上電，變頻器控制用的斷路器或空氣開關跳閘。這種情況一般是由於主電路(包括整流模塊、電解電容或逆變橋)直接擊穿短路所致，在擊穿的瞬間強烈的大電流造成模塊炸裂而產生巨大響聲。
關於模塊的損壞原因，是多方面的，不好一概而論。現僅就筆者所遇到的幾類情況加以列舉。

(1) 整流模塊的損壞大多是由於電網的污染造成的。因變頻器控制電路中使用可控整流器(如可控硅電焊機、機車充電瓶等都是可控整流器)，使電網的波形不再是規則的正弦波，使整流模塊受電網的污染而損壞，這需要增強變頻器輸入端的電源吸收能力。在變頻器內部一般也設計了該電路。但隨著電網污染程度的加深，該電路也應不斷改進，以增強吸收電網尖峰電壓的能力。

(2) 電解電容及IGBT的損壞主要是由於不均壓造成的，這包括動態均壓及靜態均壓。在使用日久的變頻器中，由於某些電容的容量減少而導致整個電容組的不均壓，分擔電壓高的電容肯定要炸裂。IGBT的損壞主要是由於母線尖蜂電壓過高而緩沖電路吸收不力造成的。在IGBT導通與關斷過程中，存在著極高的電流變化率，即di/dt，而加在IGBT上的電壓即為:
U=L×di/dt
其中L即為母線電感，當母線設計不合理，造成母線電感過高時，即會使模塊承擔的電壓過高而擊穿，擊穿的瞬間大電流造成模塊炸裂，所以減小母線電感是作好變頻器的關鍵。我們改進電路採用的寬銅排結構效果較好。國外採用的多層母線結構值得借鑒。

(3) 參數設置不合理。尤其在大慣量負載下，如離心風機、離心攪拌機等，因變頻器頻率下降時間過短，造成停機過程電機發電而使母線電壓升高，超過模塊所能承受的界限而炸裂。這種情況應盡量使下降時間放長，一般不低於300s，或在主電路中增加泄放迴路，採用耗能電阻來釋放掉該能量。如圖10所示。

圖10 耗能電阻接線圖

R即為耗能電阻。在母線電壓過高時，使A管導通，使母線電壓下降，正常後關斷。使母線電壓趨於穩定，保證主器件的安全。

(4) 當然模塊炸裂的原因還有很多。如主控晶元出現紊亂，信號干擾造成上下橋臂直通等都容易造成模塊炸裂，吸收電路不好也是其直接原因，應分別情況區別對待，以期把變頻器作的更好。

3.2 延時電阻燒壞
這主要是由於延時控制電路出問題造成的。

(1) 在變頻器延時電路中，大多是用的晶閘管(可控硅)電路，當其不導通或性能不良時，就可造成延時電阻燒壞。這主要是開機瞬間造成的。

(2) 在變頻器運行過程當中，當控制電路出現問題，有的是由於主電路模塊擊穿，造成控制電路電壓下降，使延時可控硅控制電路工作異常，可控硅截止使延時電阻燒壞。也有的是控制變壓器供電迴路出現問題，使主控板失去電壓瞬間造成晶閘管工作異常而使延時電阻燒壞。

3.3 只有頻率而無輸出
這種故障一般是IGBT的驅動電路受開關電源控制的電路中，當開關電源或其驅動的功率激勵電路出現故障時，即會出現這種問題。如圖11所示。

圖11 開關電源及其驅動電路框圖

在風光變頻器中，開關電源一般是選30～35V, ±15V或±12V，功率激勵的輸出為一方波，其幅度為±35V，頻率在7kHz左右。檢測這幾個電壓值，用示波器測量功率激勵的輸出即可加以判別，如圖12所示。但更換這部分器件後，應加以調整，使驅動板上的電壓符合規定值(+15V、-10V)為宜。

圖12 功率激勵級的輸出波形

3.4 送電後面板無顯示
這主要是提升機類變頻器常出現的故障，因此類變頻器主控板用的電源為開關電源，當其損壞時即會使主控板不正常而無顯示。
這種電源大多是其內部的熔斷器損壞造成的。因在送電的瞬間開關電源受沖擊較大，造成保險絲瞬間熔斷，可更換一個合適的熔斷器即可解決問題。有的是其內的壓敏電阻損壞，可更換一支新的開關電源。

3.5 頻率不上升
即開機後變頻器只在「2.00」Hz上運行而不上升，這主要是由於外控電壓不正常所致。變頻器的外控電壓是通過主控板的16腳端子引入的，若外控電壓不正常，或16腳的內部運放出了問題，即會引起該故障，如圖13所示。

圖13 頻率調節電路

這時請檢查調節頻率用的電位W2(3.9K)，測量一下16腳有無0～5V的電壓，進而檢測運放電路C點工作是否正常。若16腳電壓正常，而C點無輸出，一般是運放的工作電壓不正常所致，應檢查其供電電壓是否正常或運放是否損壞等。

4 結束語
變頻器所出現的故障很多，正像維修其他電器一樣，有很多是意想不到的問題，需要我們認真分析，弄清工作原理，逐步的把其電路學深學透，才能把握其本質，快速而准確的處理問題，從而更快、更好的服務於用戶。

本文只是在作者維修經驗的基礎上，對變頻器的一些常見故障進行了分析探討，在工作中還需要不斷的分析、總結，積累一些常見的維修技巧，為用戶排憂解難。也使我們的產品在應用過程中不斷改進、升華，使其做的更好，更全面、更完善地服務於廣大的用戶，盡量少出問題、不出問題，出了問題能及時解決，這正是我們的期望所在。

變頻器的控制電路及幾種常見故障分析
1 引言

隨著變頻器在工業生產中日益廣泛的應用，了解變頻器的結構，主要器件的電氣特性和一些常用參數的作用，及其常見故障越來越顯示出其重要性。

2 變頻器控制電路

給非同步電動機供電 (電壓、頻率可調)的主電路提供控制信號的迴路，稱為控制電路，如圖1所示。控制電路由以下電路組成：頻率、電壓的運算電路、主電路的電壓、電流檢測電路、電動機的速度檢測電路、將運算電路的控制信號進行放大的驅動電路，以及逆變器和電動機的保護電路。

在圖 1點劃線內，無速度檢測電路為開環控制。在控制電路增加了速度檢測電路，即增加速度指令，可以對非同步電動機的速度進行控制更精確的閉環控制。

1)運算電路將外部的速度、轉矩等指令同檢測電路的電流、電壓信號進行比較運算，決定逆變器的輸出電壓、頻率。

2)電壓、電流檢測電路

與主迴路電位隔離檢測電壓、電流等。

3)驅動電路

為驅動主電路器件的電路，它與控制電路隔離使主電路器件導通、關斷。

4)I/0輸入輸出電路

為了變頻器更好人機交互，變頻器具有多種輸入信號的輸入 (比如運行、多段速度運行等)信號，還有各種內部參數的輸出「比如電流、頻率、保護動作驅動等)信號。

5)速度檢測電路

以裝在非同步電動軸機上的速度檢測器 (TG、PLG等)的信號為速度信號，送入運算迴路，根據指令和運算可使電動機按指令速度運轉。
6)保護電路

檢測主電路的電壓、電流等，當發生過載或過電壓等異常時，為了防止逆變器和非同步電動機損壞，使逆變器停止工作或抑制電壓、電流值。

逆變器控制電路中的保護電路，可分為逆變器保護和非同步電動機保護兩種，保護功能如下

(1)逆變器保護

①瞬時過電流保護由於逆變電流負載側短路等，流過逆變器器件的電流達到異常值 (超過容許值)時，瞬時停止逆變器運轉，切斷電流。變流器的輸出電流達到異常值，也同樣停止逆變器運轉。

②過載保護
逆變器輸出電流超過額定值，且持續流通達規定的時間以上，為了防止逆變器器件、電線等損壞要停止運轉。恰當的保護需要反時限特性，採用熱繼電器或者電子熱保護 (使用電子電路)。過載是由於負載的GD2(慣性)過大或因負載過大使電動機堵轉而產生。
③再生過電壓保護
採用逆變器是電動機快速減速時，由於再生功率直流電路電壓將升高，有時超過容許值。可以採取停止逆變器運轉或停止快速減速的方法，防止過電壓。
④瞬時停電保護
對於數毫秒以內的瞬時停電，控制電路工作正常。但瞬時停電如果達數 10ms以上時，通常不僅控制電路誤動作，主電路也不能供電，所以檢出後使逆變器停止運轉。
⑤接地過電流保護
逆變器負載接地時，為了保護逆變器有時要有接地過電流保護功能。但為了確保人身安全，需要裝設漏電斷路器。
⑥冷卻風機異常
有冷卻風機的裝置，當風機異常時裝置內溫度將上升，因此採用風機熱繼電器或器件散熱片溫度感測器，檢出異常後停止逆變器。在溫度上升很小對運轉無妨礙的場合，可以省略。