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Is it possible to somehow control the speed of an induction motor?

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Hello. Currently, I am slowly making a wood lathe. I collect on the basis of the engine from a water pump. I know about the motor that it is asynchronous single-phase ("capacitor"), with a capacity of 0.45 kW. I don’t know the speed (on the nameplate - liters per minute.))) Well this was the pump))).
"Feels like" - from a thousand to one and a half ....
Question: is there any way to adjust the speed, except for the chastotnik and pulleys))). Chastotnik - expensive for "unnecessary fun", pulleys - dreary.))))
Perhaps not a long-term solution.
For the main work, these turns are suitable ... But I would like to be able to reduce them for a short period, until the workpiece is slightly balanced, and at the end for the cuts (so that it does not fly away much))) ... Or, at least , for "try" - and somehow it’s scary to immediately sharply unwind some painfully unbalanced logs ... I would like to have at least the opportunity to unwind it gradually ...
The Chinese only offer ... And here, as far as I "rummage", the dimmer will not work?
(Or maybe I don’t know how to search ??).
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46 comments
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Twice regulated asynchronous. The second case is simpler. Hangar, 12 fans scream in a bad voice and on Mondays, men are blown off their feet. I put the toggle switch on each motor in three positions - acceleration (full voltage to the engine), Off, work (through a paper capacitor, I remember, like 12.0 microfarads from some Polish lamps). They blow themselves, there is no overheating. About 8 years already working.
Another option is the dispenser feed drive, precise speed adjustment. Feedback - a disk with holes on the intermediate shaft, an optocoupler, an amplifier, an integrator, etc., a thyristor regulator. Speed ​​control - 80 ... 100% of the nominal, within these limits then it worked, I don’t know now, it was a long time ago.
Author 0
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Yes, I'm talking about dimer, and so I know)))). Yes, and already figured out that ONLY a chastotnik ...
Yes, and that machine was already assembled a long time ago ... The day before yesterday, by the way, I sharpened the next homework details ... I'll post it soon ... There is no time now ....
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Valery! I came across a similar problem. I tried the dimmer. Soldering iron, adjustable incandescent bulb. But the engine didn’t work, although the seller claimed that he would regulate. The effect was this. The engine either started or not, even without load on the shaft.
Guest Valery 0
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The speed of rotation of an induction motor does not depend on the voltage applied to it, but on a change in the frequency of the alternating current. That is, in our network the frequency of 50 GHz needs to be changed and this frequency. There are chastotniks on Aliexpress here is a link to one of them
https://en.aliexpress.com/item/VFD-motor-speed-VFD/32926450573.html
I tried to find a circuit to solder myself, until I found a sane one.
Guest Oleg 0
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what can I say. if everything is expensive and dreary. then put the gearbox. even if from the motik. choose the desired speed
+1
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Quote: Anonimus
Current limitation is due to the reduction of voltage by thyristors / triacs

Yes, not the current is limited, but time. Part of the sine wave is cut off in time.
Guest Nicholas 0
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at 6,000 rpm, induction motors do not exist and cannot exist due to physical processes. since the electromagnetic field can rotate at a maximum speed of 3000 rpm. You can increase it just by using a variable frequency drive.
Guest Nicholas 0
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the soft starter does not regulate speed, but only increases the acceleration time of the engine
Guest Nicholas 0
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buy an ordinary power regulator for aliexpress for 100 rubles, or a dimmer of the corresponding power. By changing the amplitude of the output voltage, the moment on the motor shaft will change, which means that the speed will change.
Anonimus 0
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Quote: Nruter
The soft starter for an induction motor is called VFD

Not quite so. What is called a soft starter does not change the frequency. The current is limited by reducing the voltage of the thyristors / triacs; the same dimmer by 3 phases. But this is only for the start time. But in general, the approach is basically wrong, the drive is selected by the mechanism. So either leave 1 speed or change the engine. By the way, many industrial woodworking machines are powered by engines of 6000 rpm., At 3000 the surface does not matter.
+3
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Quote: Guest Vladimir
google * buy soft starter "

Guest Vladimir, you apparently have not read the comments at all. And it would be necessary. The soft starter for an induction motor is called the VFD. It's just that VFD in the full sense can both reduce speed from nominal and increase it. And what is sold for a power tool just cuts off a portion of the supply voltage sine wave. The frequency does NOT change. Only the actual voltage value changes. And this device is intended only for collector motors.
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Not Ivan, but Valery. ;)
Guest Vladimir 0
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Ivan, google * buy a soft starter "is for sale, incl. In a separate box with 2-4 wire leads. If 0.45 kW, then 10A is enough. Should be in * 220 volts *, chipidip (here it’s probably more expensive), mb still somewhere.
Guest Alex 0
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possible, in a limited range with a drop in power. To do this, apply a constant voltage to the winding, it is enough to assemble a half-wave rectifier on one diode, with a small damping resistance and a smoothing capacitance.To supply constant voltage through a rheostat with the help of which the supplied voltage and, accordingly, the revolutions are regulated. In the old RADIO magazines (there was one for a ham radio) this circuit was used to adjust the speed of the players.
Author 0
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I’ll share it soon ... But I’m not sure that it is so successful ...))) On the contrary, I am a complete layman in turning and wooden work! Therefore, my "theorists" in practice can turn out to be a complete failure.))))
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Reply To quote A complaint
Good morning, Valery! With the concept, it is clear that very, very many manage to use the motor in this quality without shifting the bearings. I hope you share the successful design of the faceplate, I, as the owner of a homemade lathe, is also very interesting!
Author +1
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The basic requirements that I observe when making my “home” machines are sufficient “home” functionality with relative compactness !!! The machine should be easily carried by one person (including - on the stairs), should be placed in the trunk of the car, and on the shelf when not needed ...)))). Yes, and I’m not going to sharpen a large diameter on this weak motor ... For large diameters, the machine should have "more meat.")))) And then it will be heavy. Yes, and a "burned motor" (especially an asynchronous) in in my case, it is easily rewound and used, usually with greater benefit than making a grandma out of it ...))))
... therefore, only direct drive. If I really want to grind a wide plate - I’ll turn it on through the chastotnik ... Only now, then it will be tied to the workshop ... You won’t take the chastiser with you, but it’s a little expensive to buy a separate one, especially to mount it in the machine ... It’s not worth it ...
About the bearings ... Sorry, but it seems I already wrote ... If not, then I will repeat ... WELL OF FINITE THE SAME in the back cover the bearing has been replaced with a radial bearing. But does anyone think of loading radial bearings with axial load ???? I somehow didn’t even think of such a thing.)))) It needs to be a "particularly talented" mechanic.)))) .. Nah .. Of course, we throw out the "sixes", put the "seven". ))))
By the way, I’m still thinking of making a fixed plan washer. There are thoughts (and successful solutions have been found) of how it is easy to attach "spikes", a trident "or a primitive cartridge to it. And since the faceplate will be static, I want to stick a thrust bearing under it (in front of the front cover) ... (B the front one doesn’t make any sense to change the radial to the radial support one. There’s nothing to rest against there. So, I just put a simple radial, but expensive Japanese one there. It’s been verified that under load they have a resource three times higher than even the Indonesian NSK. With the Russians, sorry, I do not compare)))))
... The topic, in fact, can be deleted ... The machine is already ready and tested .. Now at the stage of "combing", as I call it ...))))
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It can still turn to the classics - several pulleys can be made of solid wood. Three or four speeds for medium workpieces will relatively solve the problem on a budget. Moreover, the ball bearings of the motor are only for radial load, while the front headstock can be thrust or tapered for axial load. The belt can be pulled under the weight of the motor, then throwing it over is a matter of ten seconds. Further, when turning large-diameter workpieces, an additional axis with a pulley can be installed for very low revolutions. Yes, as the front headstock, you can try to use the body of a burned motor.
Author +2
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Apparently, you confused me with Ivan)))). I asked questions. Ivan, like you, tried to help me ...
Thanks. The topic is already closed. Only a frequency converter can help.
A seven-circuit circuit is not suitable for this. The Bulgarian motor is a collector. It’s good for him. For the motor from the washing machine, too ... But in the asynchronous frequency is important. Even if we take a dimmer with a "pure sine wave", we get just a decrease in power, but not revolutions.
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Hello, Ivan. I wrote out such boards from China.You can still use it for a bulb, but they don’t go to the engine. I found a chip-based power regulator in the Chip & Dip online store. Well, I collected this scheme myself, but there are also ready-made ones. The price is 530 rubles, in my opinion. We connect a variable resistor, we get a power regulator. We connect a capacitor with a resistor, we get a smooth start. I applied one circuit to smoothly start the submersible vibration pump, I made the second one for adjustment, I tried it on a small grinder, it works. Well, according to your engine, I won’t say for sure, you need to try. Tomorrow at work I’ll try to connect some engine. The circuit is on a triac, and power loss is inevitable. The question is how much. Good luck to you.
+1
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I agree, it’s only a chastotnik, but when working at low revs, the motor will be very hot because revolutions are not enough for efficient airflow with a standard impeller. Therefore, it is MANDATORY to install an additional fan with independent power supply instead of the impeller.
Author +1
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Yes, I know what a chastotnik is ...
And I understand that by simply lowering the creep (even “with a clean synoid”), I just take the power off, respectively, the speed will drop (under load), but now, the currents will increase and the heating will increase ... It's like adjusting the speed with brake pads!)))).
But, for MY GOAL, and this would be suitable ... (Gradual acceleration of the workpiece with the ability to throw it back, in the case of "Akhtung")
Also came to the conclusion that "do not bother." Dimmer tried it. Jerks begin at half adjustment, and then full turns ...
+1
Reply To quote A complaint
The revolutions of the induction motor are firmly embedded in its design. You can adjust them only by changing the frequency and magnitude of the supply voltage. For this, VFD (frequency control converter) is used. The principle of operation of the VFD is 1) To rectify the voltage and increase it to 600/400 V, 2) Run the three-phase / two-phase generator (120/90 degrees), 3) Send a signal from this generator to the output drivers, which are powered by a rectified high voltage. By adjusting the frequency of the generator, change the frequency of rotation of the electric motor. In principle, nothing complicated. You can make it yourself if you really need it. And if you just need to attach an electric motor lying around somewhere, then you should not bother.
Author 0
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But not ... Understood ... For the collector ...
Author 0
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You had relatively stable operating conditions for the pump (constant load), especially a submersible one, it cooled better.
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The frequency is also not so simple, if the engine is with a phase-shifting capacitor, then everything is sharpened at 50 Hz. I would try to bungle the variator, as on a lathe type TV-125 VP. The design is simple, if desired, can be done in artisanal conditions.
Author 0
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or a checkpoint from a car,

Is that from any existing modelki ...))))))
I mean, I’m doing a “desktop toy for fun”))))). To most of the time on the shelf stood ...
+1
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About 12 years ago, a 12 kW installation for induction smelting of metals was developed. There is an inductor in the form of a spiral from a copper tube. Water was pumped into it for cooling. Water was supplied by a submersible pump (small) from the tank. So it was necessary not to supply (a lot) of water quickly and not a little, since the water in the tube boils and salt deposits and the like. I put the LATR (3ampernik) on the power of the eldwig pump and it regulated the flow of water at the outlet of the inductor by the temperature of the water. And the issue was resolved.
0
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Well, the trance from the microwave, which they throw away right away ... True, it is often cooked there. Enamel wire is wound from transes. A diameter of about 1mm. If you don’t spend a ruble (or bunnies), just put your hands on it.
The problem of speed control in asynchronous is more acute in ventilation.There is long-term operation of the electric motor and it is impossible to make it hum and smoke ... And at first they put a dimmer (cheap ketay), then they spit ... And there are still demanding customers - they need comfort (clean air), and not hum, rattle, all kinds of vibrations nea Then they put a trance with bends or an expensive chastotnik with acc. dviglom.
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I haven’t tried it myself, but judging by the literature, the dimmer can adjust the speed in the range of somewhere from half the nominal to the nominal, while the moment drops, the temperature and noise increase. But, if only for launch, then these shortcomings are insignificant.
As the grandfather of VIL said, "practice is the criterion of truth." Wait another week, suddenly someone will prompt something sensible, and then you need to try.
+2
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Quote: Valery
Quote: Pronin
No, electronics is something else. And here is electrical engineering, to be exact. And a simple (approximate) calculation. You need to power the Eldwig at ~ 450W. With coarse adjustment. If there is no LATR at 4A, take trans OSM1-0.4. Production of the Minsk plant. Disassemble (carefully), rewind the windings and wind one with taps (~ 480vit). PEL2 wire 1mm.
60 + 60 + 60 + 60 + 60 + 60 + 120 vit. Switch triacs or a powerful packet.

I’m saying I DO NOT SHARI! I have no idea where they get OSM1-0.4. and how it looks!))))
And where do they get PEL2 1mm, I don’t know either! ))))

Not LATR not Dimmer does not roll for an asynchronous. FREQUENCY ONLY .. When power is reduced, only power is reduced - there is no speed. You will press the speed with the load (with a decrease in power) - the dviglo will smoke. Moreover, if the frequency regulation is to reduce the speed, lower the frequency. In small limits, you can, slightly re-understated - smoke will go. Increasing speed and frequency - no problem. .. And therefore - either a chastotnik, or a checkpoint from a car, if you do not bother with pulleys. Although in my opinion - with pulleys easier.
Author 0
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Quote: Pronin
No, electronics is something else. And here is electrical engineering, to be exact. And a simple (approximate) calculation. You need to power the Eldwig at ~ 450W. With coarse adjustment. If there is no LATR at 4A, take trans OSM1-0.4. Production of the Minsk plant. Disassemble (carefully), rewind the windings and wind one with taps (~ 480vit). PEL2 wire 1mm.
60 + 60 + 60 + 60 + 60 + 60 + 120 vit. Switch triacs or a powerful packet.

I’m saying I DO NOT SHARI! I have no idea where they get OSM1-0.4. and how it looks!))))
And where do they get PEL2 1mm, I don’t know either! ))))
Author +1
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The reverse connection is that I’m not looking for a motor to make a machine, I am making a machine because there is a motor! )))))
Got friends asking me to come up, why the heck I need a wood turner! )))). And I really want to collect it, but what for I need it - I can’t come up with it))))).
Who has experience installing a dimer on a single phase? Strongly he "buzzes and twitches" ???
because I am inclined to the idea that a dimer is suitable for me too - I want the “humpbacked blank” not to jerk immediately with huge speed after switching on, and so that it can be easily, without a jerk, to smoothly unwind. And then sharpening - already "directly." Turnover "comfortable", verified.
Author +1
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That's right. I will say more - the idea of ​​assembling a machine tool on wood was born precisely from the fact that it was sorting through a bunch of its motors that are idle. Of the more or less suitable, there are several engines from old washers (Riga. They are also single-phase.) And an engine from hydrophore. He threw away the washing ones - he looked at the finished machine from a friend. Weak. I want to assemble a simple machine with direct drive. I don’t want to mess with the pulleys and the front headstock. He stopped at the "hydrophore". I tried it ... (I cooked it on a quick bed, grumbled a primitive tailstock, Instead of a "trident" I screwed a wing nut on the shaft and sharpened it.) It twists well. There is enough power and speed too. For the sake of interest, working as a "grandfather" chisel, he turned an egg:

ok
I decided to do it. But the hydrophore motor revealed design flaws - the flange mount, and only the “support leg” at the back! "To try" fixed something like that, but intelligently used in the project - dreary and unaesthetic!))))
But..."the monkey has already settled in my head.")))))
I had a home-made polishing machine, which I once made from a motor from a water pump. He is strong enough))) (When polishing, the motor is needed more than for emery - there you need a strong clamp, and the area of ​​the felt drum (not the disk, namely the drum) is large enough. I noticed that the nameplate on these two is the same !!! And power and liters per minute. That is, the motors differ only in caps (the pump has standard ones with “paws”). I decided to pick it up on the machine and put a polishing drum on the hydrophore.
Author 0
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Although I do not rummage, but I even paid attention to this)))))
+1
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Or maybe spit on this engine and apply a commutator engine, with which everything is clear? Or is there a goal to attach to an existing one?
0
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If there is no LATR at 4A, take trans OSM1-0.4.
I will not say categorically, I myself have not experimented, but, it seems, the speed of an induction motor depends more on frequency than on voltage. scratch
0
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Quote: Ivan_Pokhmelev
Maybe something will help.

Very "pleased" section "Frequency regulation". Apparently, the author of the article has no idea how VFD works.
0
Reply To quote A complaint
No, electronics is something else. And here is electrical engineering, to be exact. And a simple (approximate) calculation. You need to power the Eldwig at ~ 450W. With coarse adjustment. If there is no LATR at 4A, take trans OSM1-0.4. Production of the Minsk plant. Disassemble (carefully), rewind the windings and wind one with taps (~ 480vit). PEL2 wire 1mm.
60 + 60 + 60 + 60 + 60 + 60 + 120 vit. Switch triacs or a powerful packet.
Author 0
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And by e-engine - see how many conclusions the engine has. 3-phase or single-phase with add. winding (2 phase)?

I don’t rummage it in electronics.))) I just rummage about it in motors !!! krutoy
I specifically took the word "capacitor" in quotation marks so that it was clear that the motor was exactly two-phase.
Adjustment by powerful Atotransformer.

Trance - this is already "electronics".)))) This I again "don’t rummage" ... I mean, I know what it is and how it works ...
But now, to calculate the area of ​​the magnetic circuit, the cross section and the number of turns of the windings - I somehow can’t do it .... (If I could, I could. But I don’t want to rummage around for a long time and learn this topic))) Yes, and where to find it all to wrap it? )
Yes, and something even tells me that it’s not for a half-watt motor that even for a half-kilowatt motor will not be completely tiny))))
Moreover, this is not a static load, but a motor with its inherent inductions and other eddy currents ...))))) ...
(Sorry for the "self-made wording".))) I remind you: I DO NOT PRICK!))))
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Slam checkpoint from VAZ and forward

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Also sometimes there is a need for a small turning. For myself, I indicated - I need a turning chuck (cam) on the axis. Type front headstock in the primitive. And with transmission from the engine with a pulley (or gears). The engine already lies on the Hansa washing machine (with a sensor on the shaft!). We add a regulator of a turnaround on a microcircuit (there are also soldered in the Internet). China has already seen (set) for the headstock. But, how to send weight by Russian mail (?)
And by e-engine - see how many conclusions the engine has. 3-phase or single-phase with add. winding (2 phase)? Adjustment by powerful Atotransformer. And also take into account that the power will be <35% of the nominal value according to the passport.
You can of course just for a short time incl. dimmer to reduce power. And the dimmer must be more powerful.
Author 0
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The fact of the matter is that I don’t know how to "dig" ...
Remembering your recent discussions about “sharing” and “not sharing”, I will say that I - DO NOT SHARING !!! That is, I understand how the chastotnik works, but I won’t be able to assemble it for sure ... And, especially, I won’t be able to create something myself.
0
Reply To quote A complaint
PMSM, if there was a simple way, no one would bother with chastotniki. A dimmer can only lower the voltage.If, under reduced voltage, the shaft is mechanically braked, you can probably reduce the rotation speed, but I’m afraid to predict the consequences.
If you make a regulator that "bites out" not a piece of a sinusoid, but entire periods, then you get the likeness of a chastotnik, only not with a smooth, but with a discrete change in speed. It seems to me that we need to "dig" in this direction.

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