Connecting a PWM regulator. Digital PWM speed controller for commutator motor. Step-by-step assembly of an analog circuit


The PWM controller is designed to regulate the rotation speed of a polar motor, the brightness of a light bulb or the power of a heating element.

Advantages:
1 Ease of manufacture
2 Availability of components (cost does not exceed $2)
3 Wide application
4 For beginners, practice once again and please yourself =)

One day I needed a “device” to adjust the rotation speed of a cooler. I don’t remember why exactly. From the beginning I tried through normal variable resistor, it got very hot and this was not acceptable for me. As a result, after rummaging around on the Internet, I found a circuit based on the already familiar NE555 microcircuit. This was a circuit of a conventional PWM regulator with a duty cycle (duration) of pulses equal to or less than 50% (later I will give graphs of how this works). The circuit turned out to be very simple and did not require configuration; the main thing was not to mess up the connection of the diodes and transistor. The first time I assembled it on a breadboard and tested it, everything worked within half a turn. Later I laid out a small printed circuit board and everything looked neater =) Well, now let’s take a look at the circuit itself!

PWM regulator circuit

From it we see that this is a regular generator with a pulse duty cycle regulator assembled according to the circuit from the datasheet. With resistor R1 we change this duty cycle, resistor R2 serves as protection against short circuits, since pin 4 of the microcircuit is connected to ground through the internal timer switch and when R1 is in the extreme position it will simply close. R3 is a pull-up resistor. C2 is the frequency-setting capacitor. The IRFZ44N transistor is an N channel mosfet. D3 is a protective diode that prevents the field switch from failing when the load is interrupted. Now a little about the duty cycle of pulses. The duty cycle of a pulse is the ratio of its repetition period (repetition) to the pulse duration, that is, after a certain period of time there will be a transition from (roughly speaking) plus to minus, or more precisely from a logical one to a logical zero. So this period of time between pulses is that same duty cycle.


Duty ratio at middle position R1

Duty cycle at leftmost position R1


Duty ratio at the extreme right position R

Below are printed circuit boards with and without parts locations


Now a little about the details and their appearance. The microcircuit itself is made in a DIP-8 package, small-sized ceramic capacitors, and 0.125-0.25 watt resistors. The diodes are ordinary 1A rectifier diodes (the most affordable is 1N4007; there are plenty of them everywhere). The microcircuit can also be installed on a socket if in the future you want to use it in other projects and not unsolder it again. Below are photos of the details.



Another review on the topic of all sorts of things for homemade products. This time I'll talk about digital controller rpm The thing is interesting in its own way, but I wanted more.
For those interested, read on :)

Having on the farm some low-voltage devices such as a small grinder, etc. I wanted to increase their functional and aesthetic appearance a little. True, it didn’t work out, although I still hope to achieve my goal, perhaps another time, but I’ll tell you about the little thing itself today.
The manufacturer of this regulator is Maitech, or rather this name is often found on all sorts of scarves and blocks for homemade products, although for some reason I did not come across the website of this company.

Due to the fact that I didn’t end up doing what I wanted, the review will be shorter than usual, but I’ll start, as always, with how it is sold and sent.
The envelope contained a regular zip-lock bag.

The kit includes only a regulator with a variable resistor and a button, there is no hard packaging or instructions, but everything arrived intact and without damage.

There is a sticker on the back that replaces the instructions. In principle, nothing more is required for such a device.
The operating voltage range is 6-30 Volts and the maximum current is 8 Amps.

The appearance is quite good, dark “glass”, dark gray plastic of the case, when turned off it seems completely black. By appearance cool, nothing to complain about. Shipping film was glued to the front.
Installation dimensions of the device:
Length 72mm (minimum hole in case 75mm), width 40mm, depth excluding front panel 23mm (with front panel 24mm).
Front panel dimensions:
Length 42.5, mm width 80mm

A variable resistor is included with the handle; the handle is certainly rough, but it’s fine for use.
The resistor resistance is 100KOhm, the adjustment dependence is linear.
As it turned out later, 100KOhm resistance gives a glitch. When powered from a switching power supply, it is impossible to set stable readings, the interference on the wires to the variable resistor affects, which is why the readings jump +\- 2 digits, but it would be fine if they jumped, and at the same time the engine speed jumps.
The resistance of the resistor is high, the current is small and the wires collect all the noise around.
When powered from a linear power supply, this problem is completely absent.
The length of the wires to the resistor and button is about 180mm.

Button, well, nothing special here. Contacts are normally open, installation diameter 16mm, length 24mm, no backlight.
The button turns off the engine.
Those. When power is applied, the indicator turns on, the engine starts, pressing the button turns it off, a second press turns it on again.
When the engine is turned off, the indicator also does not light up.

Under the cover there is a device board.
The terminals contain power supply and motor connection contacts.
The positive contacts of the connector are connected together, the power switch switches the negative wire of the engine.
The connection of the variable resistor and the button is detachable.
Everything looks neat. The capacitor leads are a little crooked, but I think that can be forgiven :)

I will hide further disassembly under a spoiler.

More details

The indicator is quite large, the height of the digit is 14mm.
Board dimensions 69x37mm.

The board is assembled neatly, there are traces of flux near the indicator contacts, but overall the board is clean.
The board contains: a diode for protection against polarity reversal, a 5 Volt stabilizer, a microcontroller, a 470 uF 35 Volt capacitor, power elements under a small radiator.
Places for installing additional connectors are also visible, their purpose is unclear.

I sketched out a small block diagram, just for a rough understanding of what is switched and how it is connected. The variable resistor is connected with one leg to 5 Volts, the other to the ground. therefore, it can be easily replaced with a lower denomination. The diagram does not show connections to an unsoldered connector.

The device uses a microcontroller manufactured by STMicroelectronics.
As far as I know, this microcontroller is used in quite a lot different devices, for example, ampere-voltmeters.

The power stabilizer heats up when operating at maximum input voltage, but not very much.

Part of the heat from the power elements is transferred to the copper polygons of the board; on the left you can see a large number of transitions from one side of the board to the other, which helps remove heat.
Heat is also removed using a small radiator, which is pressed to power elements above. This placement of the radiator seems somewhat questionable to me, since heat is dissipated through the plastic of the case and such a radiator does not help much.
There is no paste between the power elements and the radiator, I recommend removing the radiator and coating it with paste, at least a little bit will improve.

A transistor is used in the power section, the channel resistance is 3.3 mOhm, the maximum current is 161 Amps, but the maximum voltage is only 30 Volts, so I would recommend limiting the input at 25-27 Volts. When operating at near-maximum currents, there is slight heating.
There is also a diode nearby that dampens current surges from the motor’s self-induction.
10 Amperes, 45 Volts are used here. There are no questions about the diode.


First start. It so happened that I carried out tests even before removal protective film, that’s why she’s still there in these photos.
The indicator is contrasty, moderately bright, and perfectly readable.

At first I decided to try it on small loads and received the first disappointment.
No, I have no complaints against the manufacturer or the store, I just hoped that such a relatively expensive device would have stabilization of engine speed.
Alas, this is just an adjustable PWM, the indicator displays % fill from 0 to 100%.
The regulator didn’t even notice the small motor, it’s a completely ridiculous load current :)

Attentive readers probably noticed the cross-section of the wires with which I connected the power to the regulator.
Yes, then I decided to approach the issue more globally and connected a more powerful engine.
It is, of course, noticeably more powerful than the regulator, but at idle its current is about 5 Amps, which made it possible to test the regulator in modes closer to maximum.
The regulator behaved perfectly, by the way, I forgot to point out that when turned on, the regulator smoothly increases the PWM filling from zero to the set value, ensuring smooth acceleration, while the indicator immediately shows the set value, and not like on frequency drives, where the real current one is displayed.
The regulator did not fail, it warmed up a little, but not critically.

Since the regulator is pulse, I decided, just for fun, to poke around with an oscilloscope and see what happens at the gate of the power transistor in different modes.
The PWM operating frequency is about 15 KHz and does not change during operation. The engine starts at approximately 10% fill.



Initially, I planned to install a regulator in my old (most likely ancient) power supply for a small power tool (more on that another time). In theory, it should have been installed instead of the front panel, and the speed controller should have been located on the back; I didn’t plan to install a button (fortunately, when turned on, the device immediately goes into on mode).
It had to turn out beautiful and neat.

But then some disappointment awaited me.
1. Although the indicator was slightly smaller in size than the front panel insert, what was worse was that it did not fit in depth, resting against the racks for connecting the halves of the case.
and even if the plastic of the indicator housing could have been cut off, I wouldn’t have done it anyway, since the regulator board was in the way.
2. But even if I had solved the first question, there was a second problem: I completely forgot how my power supply was made. The fact is that the regulator breaks the minus power supply, and further along the circuit I have a relay for reverse, turning on and forcibly stopping the engine, a control circuit for all this. And remaking them turned out to be much more complicated :(

If the regulator were with speed stabilization, then I would still get confused and redo the control and reverse circuit, or remake the regulator for + power switching. Otherwise, I can and will redo it, but without enthusiasm and now I don’t know when.
Maybe someone is interested, a photo of the insides of my power supply, it was assembled like this about 13-15 years ago, it worked almost all the time without problems, once I had to replace the relay.

Summary.
pros
The device is fully operational.
Neat appearance.
High quality build
The kit includes everything you need.

Minuses.
Incorrect operation from switching power supplies.
Power transistor without voltage reserve
With such modest functionality, the price is too high (but everything is relative here).

My opinion. If you close your eyes to the price of the device, then in itself it is quite good, it looks neat and works fine. Yes, there is a problem of not very good noise immunity, I think it’s not difficult to solve, but it’s a little frustrating. In addition, I recommend not to exceed the input voltage above 25-27 Volts.
What’s more frustrating is that I’ve looked quite a lot at options for all sorts of ready-made regulators, but nowhere do they offer a solution with speed stabilization. Perhaps someone will ask why I need this. I’ll explain how I came across a grinding machine with stabilization; it’s much more pleasant to work with than a regular one.

That's all, I hope it was interesting :)

The product was provided for writing a review by the store. The review was published in accordance with clause 18 of the Site Rules.

I'm planning to buy +23 Add to favorites I liked the review +38 +64

A high-quality and reliable rotation speed controller for single-phase commutator electric motors can be made using common parts in literally 1 evening. This circuit has a built-in overload detection module, provides a soft start of the controlled motor and a motor rotation speed stabilizer. This unit operates with voltages of both 220 and 110 volts.

Regulator technical parameters

  • Supply voltage: 230 volts AC
  • regulation range: 5…99%
  • load voltage: 230 V / 12 A (2.5 kW with radiator)
  • maximum power without radiator 300 W
  • low noise level
  • speed stabilization
  • soft start
  • board dimensions: 50×60 mm

Schematic diagram


Scheme of motor regulator on a triac and U2008

The control system module circuit is based on a PWM pulse generator and a motor control triac - a classic circuit design for such devices. Elements D1 and R1 ensure that the supply voltage is limited to a value that is safe for powering the generator microcircuit. Capacitor C1 is responsible for filtering the supply voltage. Elements R3, R5 and P1 are a voltage divider with the ability to regulate it, which is used to set the amount of power supplied to the load. Thanks to the use of resistor R2, which is directly included in the supply circuit to the m/s phase, indoor units synchronized with triac VT139.


Printed circuit board

The following figure shows the arrangement of elements on a printed circuit board. During installation and startup, attention should be paid to ensuring safe operating conditions - the regulator is powered by a 220V network and its elements are directly connected to the phase.

Increasing regulator power

In the test version, a BT138/800 triac with a maximum current of 12 A was used, which makes it possible to control a load of more than 2 kW. If you need to control even larger load currents, we recommend installing the thyristor outside the board on a large heatsink. You should also remember to select the correct FUSE fuse depending on the load.

In addition to controlling the speed of electric motors, you can use the circuit to adjust the brightness of lamps without any modifications.

I needed to make a speed controller for the propeller. To blow away the smoke from the soldering iron and ventilate the face. Well, just for fun, pack everything into a minimum price. The easiest way is a low-power engine direct current, of course, to regulate with a variable resistor, but to find a reduction for such a small value, and even the required power, it takes a lot of effort, and it will obviously not cost ten rubles. Therefore, our choice is PWM + MOSFET.

I took the key IRF630. Why this one MOSFET? Yes, I just got about ten of them from somewhere. So I use it, so I can install something smaller and low-power. Because the current here is unlikely to be more than an ampere, but IRF630 capable of pulling through itself under 9A. But it will be possible to make a whole cascade of fans by connecting them to one fan - enough power :)

Now it's time to think about what we will do PWM. The thought immediately suggests itself - a microcontroller. Take some Tiny12 and do it on it. I threw this thought aside instantly.

  1. I feel bad about spending such a valuable and expensive part on some kind of fan. I'll find a more interesting task for the microcontroller
  2. Writing more software for this is doubly frustrating.
  3. The supply voltage there is 12 volts, lowering it to power the MK to 5 volts is generally lazy
  4. IRF630 will not open from 5 volts, so you would also have to install a transistor here so that it supplies a high potential to the field gate. Fuck it.
What remains is the analog circuit. Well, that’s not bad either. It doesn’t require any adjustment, we’re not making a high-precision device. The details are also minimal. You just need to figure out what to do.

Op amps can be discarded outright. The fact is that for general-purpose op-amps, already after 8-10 kHz, as a rule, output voltage limit it begins to collapse sharply, and we need to jerk the fieldman. Moreover, at a supersonic frequency, so as not to squeak.


Op-amps without such a drawback cost so much that with this money you can buy a dozen of the coolest microcontrollers. Into the furnace!

Comparators remain; they do not have the ability of an op-amp to smoothly change the output voltage; they can only compare two voltages and close the output transistor based on the results of the comparison, but they do it quickly and without blocking the characteristics. I rummaged through the bottom of the barrel and couldn’t find any comparators. Ambush! More precisely it was LM339, but it was in a large case, and religion does not allow me to solder a microcircuit for more than 8 legs for such a simple task. It was also a shame to drag myself to the storehouse. What to do?

And then I remembered such a wonderful thing as analog timer - NE555. It is a kind of generator where you can set the frequency, as well as the pulse and pause duration, using a combination of resistors and a capacitor. How much different crap has been done on this timer over its more than thirty-year history... Until now, this microcircuit, despite its venerable age, is printed in millions of copies and is available in almost every warehouse for a price of a few rubles. For example, in our country it costs about 5 rubles. I rummaged through the bottom of the barrel and found a couple of pieces. ABOUT! Let's stir things up right now.


How it works
If you don’t delve deeply into the structure of the 555 timer, it’s not difficult. Roughly speaking, the timer monitors the voltage on capacitor C1, which it removes from the output THR(THRESHOLD - threshold). As soon as it reaches the maximum (the capacitor is charged), the internal transistor opens. Which closes the output DIS(DISCHARGE - discharge) to ground. At the same time, at the exit OUT a logical zero appears. The capacitor begins to discharge through DIS and when the voltage across it becomes zero ( full discharge) the system will switch to the opposite state - at output 1, the transistor is closed. The capacitor begins to charge again and everything repeats again.
The charge of capacitor C1 follows the path: “ R4->upper shoulder R1 ->D2", and the discharge along the way: D1 -> lower shoulder R1 -> DIS. When we turn the variable resistor R1, we change the ratio of the resistances of the upper and lower arms. Which, accordingly, changes the ratio of the pulse length to the pause.
The frequency is set mainly by capacitor C1 and also depends slightly on the value of resistance R1.
Resistor R3 ensures that the output is pulled to a high level - so there is an open-collector output. Which is not able to independently set a high level.

You can install any diodes, the conductors are approximately the same value, deviations within one order of magnitude do not particularly affect the quality of work. At 4.7 nanofarads set in C1, for example, the frequency drops to 18 kHz, but it is almost inaudible, apparently my hearing is no longer perfect :(

I dug into the bins, which itself calculates the operating parameters of the NE555 timer and assembled a circuit from there, for astable mode with a fill factor of less than 50%, and screwed in a variable resistor instead of R1 and R2, with which I changed the duty cycle of the output signal. You just need to pay attention to the fact that the DIS output (DISCHARGE) is via the internal timer key connected to ground, so it could not be connected directly to the potentiometer, because when twisting the regulator to its extreme position, this pin would land on Vcc. And when the transistor opens, there will be a natural short circuit and the timer with a beautiful zilch will emit magic smoke, on which, as you know, all electronics work. As soon as the smoke leaves the chip, it stops working. That's it. Therefore, we take and add another resistor for one kilo-ohm. It won’t make a difference in regulation, but it will protect against burnout.

No sooner said than done. I etched the board and soldered the components:

Everything is simple from below.
Here I am attaching a signet, in the native Sprint Layout -

And this is the voltage on the engine. A small transition process is visible. You need to put the conduit in parallel at half a microfarad and it will smooth it out.

As you can see, the frequency floats - this is understandable, since our operating frequency depends on the resistors and capacitor, and since they change, the frequency floats away, but this does not matter. Throughout the entire control range, it never enters the audible range. And the entire structure cost 35 rubles, not counting the body. So - Profit!

This homemade circuit Can be used as speed controller for 12V DC motor rated current up to 5 A or as a dimmer for 12 V halogen and LED lamps up to 50 W. Control is carried out using pulse width modulation (PWM) at a pulse repetition rate of about 200 Hz. Naturally, the frequency can be changed if necessary, selecting for maximum stability and efficiency.

Most of these structures are assembled according to a much simpler scheme. Here we present a more advanced version that uses a 7555 timer, a bipolar transistor driver and a powerful MOSFET. This design provides improved speed control and operates over a wide load range. This is indeed a very effective scheme and the cost of its parts when purchased for self-assembly is quite low.

PWM controller circuit for 12 V motor

The circuit uses a 7555 Timer to create a variable pulse width of about 200 Hz. It controls transistor Q3 (via transistors Q1 - Q2), which controls the speed of the electric motor or light bulbs.

There are many applications for this circuit that will be powered by 12V: electric motors, fans or lamps. It can be used in cars, boats and electric vehicles, in models railways and so on.

12 V LED lamps, for example LED strips, can also be safely connected here. Everyone knows that LED bulbs Much more efficient than halogen or incandescent, they will last much longer. And if necessary, power the PWM controller from 24 volts or more, since the microcircuit itself with a buffer stage has a power stabilizer.

AC Motor Speed ​​Controller

PWM controller 12 volt

Half Bridge DC Regulator Driver

Mini drill speed controller circuit

ENGINE SPEED CONTROL WITH REVERSE

Hello everyone, probably many radio amateurs, like me, have more than one hobby, but several. Beyond design electronic devices I do photography, video shooting with a DSLR camera, and video editing. As a videographer, I needed a slider for video shooting, and first I’ll briefly explain what it is. The photo below shows the factory slider.

The slider is designed for video shooting on cameras and video cameras. It is analogous to the rail system used in wide-format cinema. With its help, a smooth movement of the camera around the object being photographed is created. Another very powerful effect that can be used when working with a slider is the ability to move closer or further from the subject. The next photo shows the engine that was chosen to make the slider.

The slider is driven by a 12-volt DC motor. A diagram of a regulator for the motor that moves the slider carriage was found on the Internet. The next photo shows the power indicator on the LED, the toggle switch that controls the reverse and the power switch.

When operating such a device, it is important that there is smooth speed control, plus easy inclusion of engine reverse. The speed of rotation of the motor shaft, in the case of using our regulator, is smoothly adjusted by rotating the knob of a 5 kOhm variable resistor. Perhaps I am not the only one of the users of this site who is interested in photography, and someone else will want to replicate this device; those who wish can download an archive with a circuit diagram and printed circuit board of the regulator at the end of the article. The following figure shows circuit diagram engine regulator:

Regulator circuit

The circuit is very simple and can be easily assembled even by novice radio amateurs. Among the advantages of assembling this device, I can name its low cost and the ability to customize it to meet your needs. The figure shows the controller's printed circuit board:

But the scope of application of this regulator is not limited to sliders alone; it can easily be used as a speed regulator, for example, a machine drill, a homemade Dremel powered by 12 volts, or a computer cooler, for example, with dimensions of 80 x 80 or 120 x 120 mm. I also developed a scheme for reversing the engine, or in other words, quickly changing the rotation of the shaft in the other direction. To do this, I used a six-pin toggle switch with 2 positions. The following figure shows its connection diagram:

The middle contacts of the toggle switch, marked (+) and (-), are connected to the contacts on the board marked M1.1 and M1.2, the polarity does not matter. Everyone knows that computer coolers, when the supply voltage and, accordingly, the speed are reduced, make much less noise during operation. In the next photo, the KT805AM transistor is on the radiator:

Almost any medium and high power transistor can be used in the circuit n-p-n structures. The diode can also be replaced with analogues suitable for the current, for example 1N4001, 1N4007 and others. The motor terminals are shunted by a diode in reverse connection; this was done to protect the transistor during switch-on and switch-off moments of the circuit, since our motor has an inductive load. Also, the circuit provides an indication that the slider is turned on on an LED connected in series with a resistor.

When using an engine of greater power than shown in the photo, the transistor must be attached to the radiator to improve cooling. A photo of the resulting board is shown below:

The regulator board was manufactured using the LUT method. You can see what happened in the end in the video.

Video of work

Soon, as soon as the missing parts, mainly mechanics, are acquired, I will begin assembling the device in the case. Sent the article Alexey Sitkov .

Diagrams and overview of 220V electric motor speed controllers

To smoothly increase and decrease the shaft rotation speed, there is a special device - a 220V electric motor speed controller. Stable operation, no voltage interruptions, long service life - the advantages of using an engine speed controller for 220, 12 and 24 volts.

  • Why do you need a frequency converter?
  • Application area
  • Selecting a device
  • IF device
  • Types of devices
    • Triac device
    • Proportional Signal Process

Why do you need a frequency converter?

The function of the regulator is to invert the voltage of 12, 24 volts, ensuring smooth start and stop using pulse width modulation.

Speed ​​controllers are included in the structure of many devices, as they provide accuracy electrical control. This allows you to adjust the speed to the desired amount.

Application area

DC motor speed controller is used in many industrial and domestic applications. For example:

  • heating complex;
  • equipment drives;
  • welding machine;
  • electric ovens;
  • vacuum cleaners;
  • Sewing machines;
  • washing machines.

Selecting a device

In order to select an effective regulator, it is necessary to take into account the characteristics of the device and its intended purpose.

  1. Vector controllers are common for commutator motors, but scalar controllers are more reliable.
  2. An important selection criterion is power. It must correspond to that permitted on the unit used. It is better to exceed for safe operation of the system.
  3. The voltage must be within acceptable wide ranges.
  4. The main purpose of the regulator is to convert frequency, so this aspect must be selected according to the technical requirements.
  5. You also need to pay attention to the service life, dimensions, number of inputs.

IF device

  • AC motor natural controller;
  • drive unit;
  • additional elements.

The circuit diagram of the 12 V engine speed controller is shown in the figure. The speed is adjusted using a potentiometer. If pulses with a frequency of 8 kHz are received at the input, then the supply voltage will be 12 volts.

The device can be purchased at specialized sales points, or you can make it yourself.

AC speed controller circuit

When starting a three-phase motor at full power, current is transmitted, the action is repeated about 7 times. The current bends the motor windings, generating heat over a long period of time. A converter is an inverter that provides energy conversion. The voltage enters the regulator, where 220 volts are rectified using a diode located at the input. Then the current is filtered through 2 capacitors. PWM is generated. Next, the pulse signal is transmitted from the motor windings to a specific sinusoid.

There is a universal 12V device for brushless motors.

To save on electricity bills, our readers recommend the Electricity Saving Box. Monthly payments will be 30-50% less than they were before using the saver. It removes the reactive component from the network, resulting in a reduction in load and, as a consequence, current consumption. Electrical appliances consume less electricity and costs are reduced.

The circuit consists of two parts - logical and power. The microcontroller is located on a chip. This scheme is typical for a powerful engine. The uniqueness of the regulator lies in its use with various types engines. The circuits are powered separately; the key drivers require 12V power.

Types of devices

Triac device

The triac device is used to control lighting, power of heating elements, and rotation speed.

The controller circuit based on a triac contains a minimum of parts shown in the figure, where C1 is a capacitor, R1 is the first resistor, R2 is the second resistor.

Using a converter, power is regulated by changing the time of an open triac. If it is closed, the capacitor is charged by the load and resistors. One resistor controls the amount of current, and the second regulates the charging rate.

When the capacitor reaches the maximum voltage threshold of 12V or 24V, the switch is activated. The triac goes into the open state. When the mains voltage passes through zero, the triac is locked, and then the capacitor gives a negative charge.

Converters on electronic keys

Common thyristor regulators with a simple operating circuit.

Thyristor, works in alternating current network.

A separate type is the AC voltage stabilizer. The stabilizer contains a transformer with numerous windings.

DC stabilizer circuit

24 volt thyristor charger

To a 24 volt voltage source. The principle of operation is to charge a capacitor and a locked thyristor, and when the capacitor reaches voltage, the thyristor sends current to the load.

Proportional Signal Process

Signals arriving at the system input form feedback. Let's take a closer look using a microcircuit.

Chip TDA 1085

The TDA 1085 chip pictured above provides feedback control of a 12V, 24V motor without loss of power. It is mandatory to contain a tachometer, which provides feedback from the engine to the control board. The stabilization sensor signal goes to a microcircuit, which transmits the task to the power elements - to add voltage to the motor. When the shaft is loaded, the board increases the voltage and the power increases. By releasing the shaft, the tension decreases. The revolutions will be constant, but the power torque will not change. The frequency is controlled over a wide range. Such a 12, 24 volt motor is installed in washing machines.

With your own hands you can make a device for a grinder, wood lathe, sharpener, concrete mixer, straw cutter, lawn mower, wood splitter and much more.

Industrial regulators, consisting of 12, 24 volt controllers, are filled with resin and therefore cannot be repaired. Therefore, a 12V device is often made independently. A simple option using the U2008B chip. The controller uses current feedback or soft start. If the latter is used, elements C1, R4 are required, jumper X1 is not needed, but when feedback vice versa.

When assembling the regulator, choose the right resistor. Since with a large resistor there may be jerks at the start, and with a small resistor the compensation will be insufficient.

Important! When adjusting the power controller, you need to remember that all parts of the device are connected to the AC network, so safety precautions must be observed!

Speed ​​controllers for single-phase and three-phase 24, 12 volt motors are a functional and valuable device, both in everyday life and in industry.

Rotation controller for motor

On simple mechanisms it is convenient to install analog current regulators. For example, they can change the speed of rotation of the motor shaft. From the technical side, implementing such a regulator is simple (you will need to install one transistor). Suitable for adjusting independent speed of motors in robotics and power supplies. The most common types of regulators are single-channel and two-channel.

Video No. 1. Single-channel regulator in operation. Changes the rotation speed of the motor shaft by rotating the variable resistor knob.

Video No. 2. Increasing the rotation speed of the motor shaft when operating a single-channel regulator. An increase in the number of revolutions from the minimum to the maximum value when rotating the variable resistor knob.

Video No. 3. Two-channel regulator in operation. Independent setting of the torsion speed of motor shafts based on trimming resistors.

Video No. 4. The voltage at the output of the regulator was measured with a digital multimeter. The resulting value is equal to the battery voltage, from which 0.6 volts have been subtracted (the difference arises due to the voltage drop across the transistor junction). When using a 9.55 volt battery, a change from 0 to 8.9 volts is recorded.

Functions and main characteristics

The load current of single-channel (photo 1) and two-channel (photo 2) regulators does not exceed 1.5 A. Therefore, to increase the load capacity, the KT815A transistor is replaced with KT972A. The numbering of the pins for these transistors is the same (e-k-b). But the KT972A model is operational with currents up to 4A.

Single channel motor controller

The device controls one motor, powered by voltage in the range from 2 to 12 volts.

Device design

The main design elements of the regulator are shown in the photo. 3. The device consists of five components: two variable resistance resistors with a resistance of 10 kOhm (No. 1) and 1 kOhm (No. 2), a transistor model KT815A (No. 3), a pair of two-section screw terminal blocks for the output for connecting a motor (No. 4) and input for connecting a battery (No. 5).

Note 1. Installation of screw terminal blocks is not necessary. Using a thin stranded mounting wire, you can connect the motor and power source directly.

Principle of operation

The operating procedure of the motor controller is described in the electrical diagram (Fig. 1). Taking into account the polarity, a constant voltage is supplied to the XT1 connector. The light bulb or motor is connected to the XT2 connector. A variable resistor R1 is turned on at the input; rotating its knob changes the potential at the middle output as opposed to the minus of the battery. Through current limiter R2, the middle output is connected to the base terminal of transistor VT1. In this case, the transistor is switched on according to a regular current circuit. The positive potential at the base output increases as the middle output moves upward from the smooth rotation of the variable resistor knob. There is an increase in current, which is due to a decrease in the resistance of the collector-emitter junction in transistor VT1. The potential will decrease if the situation is reversed.

Electrical circuit diagram

Materials and details

A printed circuit board measuring 20x30 mm is required, made of a fiberglass sheet foiled on one side (permissible thickness 1-1.5 mm). Table 1 provides a list of radio components.

Note 2. The variable resistor required for the device can be of any manufacture; it is important to observe the current resistance values ​​​​for it indicated in Table 1.

Note 3. To regulate currents above 1.5A, the KT815G transistor is replaced with a more powerful KT972A (with a maximum current of 4A). At the same time, the drawing printed circuit board no need to change, since the pin distribution of both transistors is identical.

Build process

For further work, you need to download the archive file located at the end of the article, unzip it and print it. The regulator drawing (termo1 file) is printed on glossy paper, and the installation drawing (montag1 file) is printed on a white office sheet (A4 format).

Next, the drawing of the circuit board (No. 1 in photo. 4) is glued to the current-carrying tracks on the opposite side of the printed circuit board (No. 2 in photo. 4). It is necessary to make holes (No. 3 in photo. 14) on the installation drawing in the mounting locations. The installation drawing is attached to the printed circuit board with dry glue, and the holes must match. Photo 5 shows the pinout of the KT815 transistor.

The input and output of terminal blocks-connectors are marked in white. A voltage source is connected to the terminal block via a clip. A fully assembled single-channel regulator is shown in the photo. The power source (9 volt battery) is connected at the final stage of assembly. Now you can adjust the shaft rotation speed using the motor; to do this, you need to smoothly rotate the variable resistor adjustment knob.

To test the device, you need to print a disk drawing from the archive. Next, you need to paste this drawing (No. 1) onto thick and thin cardboard paper (No. 2). Then, using scissors, a disc is cut out (No. 3).

The resulting workpiece is turned over (No. 1) and a square of black electrical tape (No. 2) is attached to the center for better adhesion of the surface of the motor shaft to the disk. You need to make a hole (No. 3) as shown in the image. Then the disk is installed on the motor shaft and testing can begin. The single-channel motor controller is ready!

Two-channel motor controller

Used to independently control a pair of motors simultaneously. Power is supplied from a voltage ranging from 2 to 12 volts. The load current is rated up to 1.5A per channel.

The main components of the design are shown in photo.10 and include: two trimming resistors for adjusting the 2nd channel (No. 1) and the 1st channel (No. 2), three two-section screw terminal blocks for output to the 2nd motor (No. 3), for output to the 1st motor (No. 4) and for input (No. 5).

Note:1 Installation of screw terminal blocks is optional. Using a thin stranded mounting wire, you can connect the motor and power source directly.

Principle of operation

The circuit of the two-channel regulator is identical electrical diagram single-channel regulator. Consists of two parts (Fig. 2). The main difference: the variable resistance resistor is replaced with a trimming resistor. The rotation speed of the shafts is set in advance.

Note.2. To quickly adjust the rotation speed of the motors, the trimming resistors are replaced using a mounting wire with variable resistance resistors with the resistance values ​​indicated in the diagram.

Materials and details

You will need a printed circuit board measuring 30x30 mm, made of a fiberglass sheet foiled on one side with a thickness of 1-1.5 mm. Table 2 provides a list of radio components.

Build process

After downloading the archive file located at the end of the article, you need to unzip it and print it. The regulator drawing for thermal transfer (termo2 file) is printed on glossy paper, and the installation drawing (montag2 file) is printed on a white office sheet (A4 format).

The circuit board drawing is glued to the current-carrying tracks on the opposite side of the printed circuit board. Form holes on the installation drawing in the mounting locations. The installation drawing is attached to the printed circuit board with dry glue, and the holes must match. The KT815 transistor is being pinned. To check, you need to temporarily connect inputs 1 and 2 with a mounting wire.

Any of the inputs is connected to the pole of the power source (a 9-volt battery is shown in the example). The negative of the power supply is attached to the center of the terminal block. It is important to remember: the black wire is “-” and the red wire is “+”.

The motors must be connected to two terminal blocks, and it is also necessary to install desired speed. After successful testing, you need to remove the temporary connection of the inputs and install the device on the robot model. The two-channel motor controller is ready!

THE ARCHIVE contains the necessary diagrams and drawings for the work. The emitters of the transistors are marked with red arrows.

DC motor speed controller diagram

The DC motor speed controller circuit operates on the principles of pulse width modulation and is used to change the speed of a 12 volt DC motor. Regulating the engine shaft speed using pulse-width modulation gives greater efficiency than using simple change constant voltage supplied to the engine, although we will also consider these circuits

DC motor speed controller circuit for 12 volts

The motor is connected in a circuit to a field-effect transistor which is controlled by pulse-width modulation carried out on the NE555 timer chip, which is why the circuit turned out to be so simple.

The PWM controller is implemented using a conventional pulse generator on an astable multivibrator, generating pulses with a repetition rate of 50 Hz and built on the popular NE555 timer. Signals coming from the multivibrator create a bias field at the gate field effect transistor. The duration of the positive pulse is adjusted using variable resistance R2. The longer the duration of the positive pulse arriving at the gate of the field-effect transistor, the high power supplied to the DC motor. And vice versa, the shorter the pulse duration, the weaker the electric motor rotates. This scheme works great from battery at 12 volts.

DC motor speed control circuit for 6 volts

The speed of the 6 volt motor can be adjusted within 5-95%

Engine speed controller on PIC controller

Speed ​​control in this circuit is achieved by applying voltage pulses of varying duration to the electric motor. For these purposes, PWM (pulse width modulators) are used. In this case, pulse width control is provided microcontroller PIC. To control the engine rotation speed, two buttons SB1 and SB2, “More” and “Less,” are used. You can change the rotation speed only when the “Start” toggle switch is pressed. The pulse duration varies, as a percentage of the period, from 30 to 100%.

As a voltage stabilizer for the PIC16F628A microcontroller, a three-pin KR1158EN5V stabilizer is used, which has a low input-output voltage drop, only about 0.6V. The maximum input voltage is 30V. All this allows the use of motors with voltages from 6V to 27V. The KT829A composite transistor is used as a power switch, which is preferably installed on a radiator.

The device is assembled on a printed circuit board measuring 61 x 52 mm. You can download the PCB drawing and firmware file from the link above. (See folder in the archive 027-el)




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