Hmph, you know what? Speaking of yourself and proficient, in fact, the complexity of the frequency conversion speed control device, that is not what you can imagine!

Du Youwen is now full of confidence, after all, although he has not read the report that Qin Zhenhua said, but when he was in the secondary school, he had learned, this kind of inverter, first AC to DC, and then DC to AC, the second step, that is to pass through the thyristor.

The waveform of the power grid presents a perfect sine waveform, and it is because of this waveform that the motor can run perfectly, and the change through the thyristor is almost a square wave, the performance is very poor, and there is almost no practical value.

Du Youwen pulled out the thyristor and sine wave in front of everyone, and said it very mysteriously, proving that his knowledge was very profound, and hearing his words, Qin Zhenhua shook his head helplessly: "The thyristor has long been outdated, and now it is a switch tube, and SPWM technology is installed to control it, if you use an oscilloscope to see it, there is no difference between it and our sine wave." ”

Du Youwen is dragging professional terms, so Qin Zhenhua is dragging more professional technical terms, SPWM, do you understand?

Qin Zhenhua still entered the factory, idle, and did not need to prepare for the college entrance examination, before he read this kind of technical information, if Qin Zhenhua is described in a word in later generations, it is a thorough scholar.

“SPWM？” Du Youwen tried hard to repeat these letters, and this lame rereading made Wang Xiaoyu below suddenly burst out laughing, this Qin Zhenhua is really powerful, well, it's like Zhuge Liang's tongue battle group Confucianism.

At this time, the workers below looked at each other, for most people, this big competition is definitely a high standard, so high that they have become spectators, and it is impossible to play.

"That's right, if translated, it's called pulse width modulation." Qin Zhenhua began to explain: "Mathematically speaking, a continuous function can be approximated or replaced by an infinite number of discrete functions, so it can be conceived to replace the sine wave with a plurality of rectangular pulse waves of different amplitudes. ”

"Okay, let's not explain the theory, in practice, this technique is now widely used." Qin Zhenhua said: "For example, SA8281 is an integrated circuit launched by MITEL for three-phase SPWM wave generation and control, if our machine factory can buy this kind of component from the international market, I can make our three-phase motor inverter, in the future, our lathe, no longer need to move various reducers, directly can electronic speed regulation." ”

"It would be nice if our lathes could electronically regulate the speed." There is already a master talking about it below, when we are processing, different workpieces, different speeds, sometimes can not find a suitable ratio, and now, if the speed is continuously adjustable, it will be easier to process.

"Bragging, why haven't I heard of it?" Qin Zhenhua explained endlessly, just like an expert, Du Youwen's brain became more and more sober, and a certain article he had read had some impression, as if there was a letter missing?

"If you want to say the most advanced, it should be PWM, yes, I'm sure." Du Youwen said: "Your amateur level, it's good to be able to talk about it here." ”

I'm from the R&D room, I'm an old senior, you are in front of me, don't want to pretend, this is a big knife in front of Guan Gong!

Qin Zhenhua shook his head helplessly: "Do you know the meaning of these letters?" Do you know what the S in front of you means? ”

"You know what?" Du Youwen asked rhetorically, if you want to deceive me, it's not so easy, I studied Russian, and it's not easy to know these letters.

"The S in front of you is Sinusoidal, which means sine wave, without S, the output is a square wave, and the thyristor you are talking about is that thing. It's already a generation behind, is our factory R&D room at your level? One bottle is not satisfied, and half a bottle is dangling. "Qin Zhenhua didn't save face for him, this Niu Shilong and Du Youwen sang and harmonized, making it clear that the two of them were doing ghosts.

Du Youwen was annoyed when he heard it, am I a half-ass? That's better than you, too! However, before he could say anything, he saw Wu Limin, who was quick with his hands and feet, trotting all the way up to the rostrum, holding the magazines of last year's whole year nailed together, and shouting in his mouth: "Factory director, factory director, our data room, fully support our big competition!" ”

Seeing the information, Ma Panshan beckoned, took it, looked at it, and there was a smile on his face: "Yes, Qin Zhenhua, your memory is really good, you will remember it after reading it, your request, the factory has approved, and you will apply to your superiors, import the kind of parts you said, and make this kind of governor, here, I will give you a celebration party!" ”

Ma Panshan expressed his attitude, although it was a few simple words, he completely agreed with Qin Zhenhua's statement.

Qin Zhenhua, well done!

Wang Xiaoyu couldn't help but applaud again, Director Ma said that he wanted to hold a celebration party! Of course, this is worth celebrating, as soon as she failed like this, the entire auditorium also applauded, and it was not clear whether it was applause for Director Ma or Qin Zhenhua.

Niu Shilong quickly calmed down, it doesn't matter, and then, the third question, I don't believe you will!

Du Youwen also suppressed his mood, and read out the next question, a professional question about the tank engine, and there are specific numerical questions on it, Qin Zhenhua, will you?

Qin Zhenhua finished answering easily.

Then, the fourth question, the fifth question, one question after another, Du Youwen was completely confused, how could he do it? You know, these questions are specially prepared for Qin Zhenhua, they are the most bizarre questions, even he can't do it himself, Qin Zhenhua can actually answer it, what does it mean?

Qin Zhenhua's theoretical foundation is higher than himself? How is this possible? I'm a secondary school student!

Don't underestimate secondary school students, now to be able to study secondary school, it is already very remarkable, into the factory, that is also the cadre level treatment!

Of course, it's just in terms of treatment, if you want to be a cadre, you have to stay up for a few more years, what kind of results will you produce, Qin Zhenhua? What is he?

Only the most unpromising people will go to high school!

However, it is unbelievable that such a person has such a wide range of knowledge.

I don't believe it's hard for you!

Finally, the last question, when he saw this question, Du Youwen felt a little empty.

After a night of questions, who can stand it, the last question is even more sloppy, and even he can't see it clearly!

Where did you copy this question? Forgot about it! This handwriting is also not legible, Du Youwen tried hard to identify it, but, helplessly, this handwriting is similar to the handwriting of the doctor's prescription, who can know!

"Please describe the Type 63 armored car, hydraulic suspension ... How the system works. Du Youwen guessed and recalled, and finally finished reading the topic.