Do-it-yourself speed controller with feedback. Regulator of revolutions of the collector engine: device and manufacture by hand

Any modern power tool or household appliance uses a brushed motor. This is due to their versatility, i.e., the ability to operate from both AC and DC voltage. Another advantage is the effective starting torque.

However, not all users are satisfied with the high speed of the collector engine. For a smooth start-up and the ability to change the speed of rotation, a regulator was invented, which is quite possible to make by hand.

The principle of operation and varieties of collector motors

Each electric motor consists of a collector, stator, rotor and brushes. The principle of its operation is quite simple:

In addition to the standard device, there are also:

Regulator device

There are many schemes of such devices in the world. Nevertheless, all of them can be divided into 2 groups: standard and modified products.

Standard device

Typical products are distinguished by the simplicity in the manufacture of the Idinistor, good reliability when changing the engine speed. As a rule, such models are based on thyristor regulators. The principle of operation of such schemes is quite simple:

Thus, the speed of the collector motor is regulated. In most cases, a similar scheme is used in foreign household vacuum cleaners. However, you should be aware that such a speed controller does not have feedback... Therefore, when the load changes, you will have to adjust the speed of the electric motor.

Modified schemas

Of course, the standard device suits many fans of speed controllers to "dig" into electronics. However, without progress and improvement of products, we would still live in the Stone Age. Therefore, more interesting schemes are constantly being invented, which many manufacturers are happy to use.

The most commonly used rheostat and integral controllers. As the name implies, the first option is based on a rheostat circuit. In the second case, an integral timer is used.

Rheostats are effective in changing the number of revolutions of the collector motor. The high efficiency is due to the power transistors, which take some of the voltage. Thus, the current flow is reduced and the motor runs with less zeal.

Video: device of the speed control with maintaining power

The main disadvantage of this scheme is the large amount of heat generated. Therefore, for trouble-free operation, the regulator must be constantly cooled. Moreover, the cooling of the device must be intense.

A different approach is implemented in an integral controller, where an integral timer is responsible for the load. As a rule, transistors of almost any name are used in such circuits. This is due to the fact that the composition contains a microcircuit with large values \u200b\u200bof the output current.

If the load is less than 0.1 ampere, then all the voltage goes directly to the microcircuit, bypassing the transistors. However, for the regulator to work effectively, it is necessary that the gate voltage be 12V. Therefore, the electrical circuit and the voltage of the supply itself must correspond to this range.

Overview of typical circuits

It is possible to regulate the rotation of the shaft of a low-power electric motor by serial connection of a power resistor with a lack. However, this option has a very low efficiency and the absence of the possibility of smooth speed change. To avoid such a nuisance, you should consider several regulator schemes that are most often used.

As you know, PWM has a constant pulse amplitude. In addition, the amplitude is identical to the supply voltage. Consequently, the electric motor will not stop, even at low speeds.

The second option is similar to the first. The only difference is that an operational amplifier is used as a master oscillator. This component has a frequency of 500 Hz and is engaged in the generation of pulses that have a triangular shape. Regulation is also carried out with a variable resistor.

How to do it yourself

If you do not want to spend money on purchasing a finished device, you can make it yourself. In this way, you can not only save money, but also gain a rewarding experience. So, for making thyristor regulator required:

• soldering iron (to test the functionality);
• wires;
• thyristor, capacitors and resistors;
• scheme.

As you can see from the diagram, only 1 half-cycle is controlled by the regulator. However, this will be quite enough for testing operability on an ordinary soldering iron.

If the knowledge of decoding the scheme is not enough, you can familiarize yourself with the text version:

The use of regulators allows more economical use of electric motors. In certain situations, such a device can be made independently. However, for more serious purposes (for example, control of heating equipment), it is better to purchase a ready-made model. Fortunately, there is a wide selection of such products on the market, and the price is quite affordable.

The regulator circuit, with the help of which the engine or fan speed is changed, is designed to operate on a 220 volt AC mains.

The motor together with the power thyristor VS2 is connected to the diagonal of the diode bridge VD3, while the other is fed mains voltage alternating current 220 volts. In addition, this thyristor monitors with sufficiently wide pulses, so that short circuit breaks with which all collector motors work do not affect the stable operation of the circuit.

The first thyristor is controlled by the transistor VT1, which is connected according to the pulse generator circuit. As soon as the voltage across the capacitor becomes sufficient to open the first transistor, a positive pulse will be sent to the control terminal of the thyristor. The thyristor will open and now a long control pulse will appear on the second thyristor. And already from it, the voltage, which actually affects the speed, goes to the engine.

The speed of rotation of the electric motor is adjusted with a variable resistance R1. Since an inductive load is connected to the circuit of the second thyristor, a spontaneous opening of the thyristor is possible, even in the absence of a control signal. Therefore, to block this, a diode VD2 is included in the circuit, which is connected in parallel with the motor winding L1.

When tuning the engine speed governor circuit, it is advisable to use one that can measure the speed of the electric motor or a conventional dial voltmeter for alternating current, which is connected in parallel with the engine.

By selecting the resistance R3, the voltage range is set from 90 to 220 volts. If at minimum speed the motor does not work correctly, then it is required to reduce the value of the resistor R2.

This circuit works well for adjusting fan speed based on temperature.

It is used as a sensing element. As a result of its heating, its resistance decreases, and therefore, at the output of the operational amplifier, on the contrary, the voltage increases and controls the fan speed through the field-effect transistor.

Variable resistance P1 - you can set the lowest fan speed at the lowest temperature, and variable resistance P2 regulate the highest rotation speed at the maximum temperature.

Under normal conditions, we adjust the minimum engine speed with a resistor P1. Then the sensor is heated and the required fan speed is set with the resistance P2.

The circuit controls fan speed based on temperature readings, using the usual NTC.

The circuit is so simple that there are only three radio components in it: an adjustable voltage regulator LM317T and two resistors forming a voltage divider. One of the resistors is a NTC thermistor and the other is a conventional resistor. To simplify the assembly, I give a picture of the printed circuit board below.

In order to save money, you can equip a standard grinder with a speed regulator. Such a regulator for grinding the cases of various electronic equipment is an indispensable tool in the arsenal of a radio amateur.

The U2008B microcircuit is a PWM regulator of revolutions of AC collector motors. Manufactured by TELEFUNKEN, most often it can be seen in the control circuit of an electric drill, a stepping saw, a jigsaw, etc., and also works with motors from vacuum cleaners, allowing you to adjust traction. Built-in soft start circuit significantly extends the life of the engines. Control circuits based on this chip can also be used to control power, for example, heaters.

All modern drills are produced with built-in engine speed controllers, but for sure, in the arsenal of every radio amateur there is an old Soviet drill, in which the change in the speed was not conceived, which dramatically reduces the operational characteristics.

You can adjust the rotation speed of an asynchronous brushless motor by adjusting the frequency of the supply AC voltage. This scheme allows you to adjust the rotation speed in a fairly wide range - from 1000 to 4000 rpm.

When using an electric motor in tools, one of the serious problems is adjusting the speed of their rotation. If the speed is not high enough, then the tool is not effective enough.

If it is too high, then this leads not only to a significant waste of electrical energy, but also to a possible burnout of the instrument. If the rotation speed is too high, the performance of the tool may also become less predictable. How to fix it? For this purpose, it is customary to use a special speed controller.

A motor for power tools and household appliances usually falls into one of 2 main types:

1. Collector motors.
2. Asynchronous motors.

In the past, the second of these categories was most prevalent. Now, about 85% of motors used in electrical tools, household or kitchen appliances are of the collector type. This is explained by the fact that they have a greater degree of compactness, they are more powerful and the process of managing them is simpler.

The operation of any electric motor is based on a very simple principle:if a rectangular frame is placed between the poles of the magnet, which can rotate around its axis, and a direct current is sent through it, then the frame will turn. The direction of rotation is determined according to the "right hand rule".

This pattern can be used for the operation of a collector motor.

The important point here is the connection of current to this frame. Since it rotates, special sliding contacts are used for this. After the frame rotates 180 degrees, current flows through these contacts in the opposite direction. Thus, the direction of rotation remains the same. At the same time, smooth rotation will not work. To achieve this effect, it is customary to use several dozen frames.

Device

The collector motor usually consists of a rotor (armature), stator, brushes and a tachogenerator:

1. Rotor is a rotating part, the stator is an external magnet.
2. Brushes made of graphite - this is the main part of sliding contacts through which voltage is applied to the rotating armature.
3. TachogeneratorIs a device that monitors rotation characteristics. In the event of a violation of the uniformity of movement, it corrects the voltage entering the motor, thereby making it smoother.
4. Stator may contain not one magnet, but, for example, 2 (2 pairs of poles). Also, instead of static magnets, electromagnet coils can be used here. Such a motor can work from both direct and alternating current.

The ease of adjusting the speed of the collector motor is determined by the fact that the rotation speed directly depends on the magnitude of the applied voltage.

In addition, an important feature is that the axis of rotation can be directly connected to the rotating tools without the use of intermediate mechanisms.

If we talk about their classification, then we can talk about:

1. Brush motors direct current.
2. Brush motors alternating current.

In this case, we are talking about what kind of current the electric motors are powered by.

The classification can also be made according to the principle of motor excitation. In the device of the collector motor, power supply is supplied to both the rotor and the stator of the motor (if electromagnets are used in it).

The difference is how these connections are organized.

It is customary to distinguish between:

• Parallel excitation.
• Consistent arousal.
• Parallel-sequential excitation.

Adjustment

Now let's talk about how you can regulate the speed of the collector motors. Due to the fact that the speed of rotation of the motor simply depends on the magnitude of the supplied voltage, then any means of adjustment that are capable of performing this function are quite suitable for this.

Let's list a few of these options for example:

1. Laboratory autotransformer (LATR).
2. Factory adjustment boardsused in household appliances (you can use in particular those used in mixers or vacuum cleaners).
3. Buttonsused in the construction of power tools.
4. Household regulators lighting with smooth action.

However, all of the above methods have a very important flaw. Together with a decrease in revolutions, the power of the motor also decreases. In some cases, it can be stopped even with just your hand. In some cases, this may be acceptable, but for the most part, it is a serious obstacle.

A good option is to perform speed control by using a tachogenerator. It is usually installed at the factory. In case of deviations in the speed of rotation of the motor, the already corrected power supply corresponding to the required speed of rotation is transmitted to the motor. If the motor rotation control is built into this circuit, then there will be no power loss.

How does it look constructive? The most common rheostat control of rotation, and made on the basis of the use of semiconductors.

In the first case, we are talking about a variable resistance with mechanical adjustment. It is connected in series to the collector motor. The disadvantage is additional heat generation and additional waste of battery life. With this method of adjustment, there is a loss of motor rotation power. It is a cheap solution. Not applicable for sufficiently powerful motors for the reasons mentioned.

In the second case, when using semiconductors, the motor is controlled by sending certain pulses. The circuit can change the duration of such pulses, which in turn changes the rotation speed without loss of power.

How to make it yourself?

There are various options for adjustment schemes. Let's give one of them in more detail.

Here's how it works:

Originally, this device was designed to adjust the commutator motor in electric vehicles. It was about one where the supply voltage is 24 V, but this design is applicable to other motors.

The weak point of the circuit, which was determined during tests of its operation, is its poor suitability at very high amperage values. This is due to some slowdown in the operation of the transistor circuit elements.

It is recommended that the current be no more than 70 A. There is no current and temperature protection in this circuit, therefore it is recommended to build in an ammeter and monitor the current strength visually. The switching frequency will be 5 kHz, it is determined by the capacitor C2 with a capacity of 20 nF.

When the current strength changes, this frequency can change between 3 kHz and 5 kHz. The variable resistor R2 is used to adjust the current. When using the electric motor in a domestic environment, it is recommended to use a standard type regulator.

At the same time, it is recommended to select the value of R1 in such a way as to correctly adjust the operation of the regulator. From the output of the microcircuit, the control pulse goes to a push-pull amplifier based on transistors KT815 and KT816, then it goes to transistors.

The printed circuit board has a size of 50 by 50 mm and is made of one-sided fiberglass:

This diagram additionally shows 2 45 ohm resistors. This is done for the possible connection of a conventional computer fan to cool the device. When using an electric motor as a load, it is necessary to block the circuit with a blocking (damper) diode, which, by its characteristics, corresponds to twice the value of the load current and twice the value of the supply voltage.

Operation of the device in the absence of such a diode may lead to damage due to possible overheating. In this case, the diode will need to be placed on the heat sink. To do this, you can use a metal plate that has an area of \u200b\u200b30 cm2.

Regulating switches work in such a way that the power losses on them are small enough. IN In the original circuit, a standard computer fan was used. To connect it, a limiting resistance of 100 Ohm and a supply voltage of 24 V.

The assembled device looks like this:

When manufacturing a power unit (in the lower figure), the wires must be connected in such a way that there are a minimum of bends in those conductors through which large currents pass. We see that the manufacture of such a device requires certain professional knowledge and skills. Perhaps in some cases it makes sense to use a purchased device.

Selection criteria and cost

In order to correctly choose the most suitable type of regulator, you need to have a good idea of \u200b\u200bthe types of such devices:

1. Various types of control. There can be a vector or scalar control system. The former are used more often, while the latter are considered more reliable.
2. Regulator power must correspond to the maximum possible motor power.
3. By voltage it is convenient to choose the device with the most versatile properties.
4. Frequency characteristics. The regulator that suits you should match the most high frequencythat the motor uses.
5. Other characteristics. Here we are talking about the size of the warranty period, dimensions and other characteristics.

Depending on the purpose and consumer properties, the prices for regulators can vary significantly.

For the most part, they are in the range from about 3.5 thousand rubles to 9 thousand:

1. Speed \u200b\u200bcontroller KA-18 ESCdesigned for 1:10 scale models. It costs 6890 rubles.
2. MEGA speed controller collector (waterproof). It costs 3605 rubles.
3. Speed \u200b\u200bgovernor for LaTrax 1:18 models. Its price is 5690 rubles.

65 rub.

Description:

More details:

The module is a small board with all the necessary elements for strapping and built on a microcircuit TDA1085c... A prerequisite for connection is the presence of a tachometer (tachogenerator), which allows you to provide feedback of the electric motor with the microcircuit. When the engine is loaded, the speed begins to drop, which is fixed by the tachometer, which instructs the microcircuit to increase the voltage and vice versa, when the load weakens, the voltage to the engine drops. Thus, this design allows maintain constant power collector motor when changing the rotor speed.

The the module is well suited to the electric motor from washing machine machine... In combination of two devices, you can easily do it yourself: Wood lathe, Milling machine, Honey extractor, Lawn mower, Potter's wheel, Wood splitter, Emery, Drilling machine, Feeder cutter and other devices where the rotation of mechanisms is necessary.

There is an option on the capacitor type of power supply:

The cost of this board 55,00 BYN.

Connection

To connect the collector motor to the control board, you need punderstand the pinout of the wires. The standard collector motor has 3 contact groups: tachometer, brushes and stator winding. Rarely, but 4 groups of thermal protection contacts may also be present (wires are usually white).

Tachometer: located at the rear of the engine with outgoing wires (smaller in cross section than the others). The wires may ring with a multimeter and may have little resistance.

Brushes: the wires are ringed with each other and the engine manifold.

Winding: the wires have 2 or 3 pins (with a midpoint). The wires ring out to each other.

When connecting a collector motor to a 220 Volt network:

We short-circuit one end of the wires of the brush and winding (or put a jumper in the terminal block), connect the other end of the wires to the 220V network. The direction of rotation of the motor will depend on which of the winding wires will be connected to the 220V network. If it is necessary to change the direction of movement of the motor, put a jumper on the other pair of wires "winding-brush".

When connecting a collector motor to the speed controller board:

The wires that connected the engine to the 220V network are connected to the terminal " M "... To terminal " Taho " we connect the tachometer. To terminal "L N" connect mains supply 220 volt. Polarity doesn't matter.

The kit includes a switch (terminal SA). If the switch is not needed, put a jumper.

Setting up

The board provides 3 types of settings:

Adjusting the smoothness of the speed set

Setting up a tachometer;

Setting the speed control range.

For reliability in operation and correct settings, it is recommended to perform the settings in the following sequence:

1) Hadjustment of the smoothness of the set of revolutions R1, which is responsible for the smoothness of the set of revolutions of the collector engine.

2) Setting up the tachometer performed by a trimming resistor R3, which allows you to remove jerks and jerking in the engine when adjusting the rotation speed.

3) Setting the speed control range performed by a trimming resistor R2... The setting allows you to limit or increase the minimum number of revolutions of the collector motor, even with the minimum potentiometer turned out.

Reverse connection

To connect the reversing switch, remove the jumper in the motor (winding and brushes). The wires in the switch are separated by three pairs of wires, one of which has tinned ends. A pair with tinned ends is connected to the M terminal. The two remaining pairs are connected to the winding and brushes. Which pair will be connected to the winding or brushes does not matter. The polarity of the connection does not matter.

A pair of wires for connecting to the motor tachometer is green or black.

The reversing switch is not included in the standard package of the board and must be purchased separately.

Reverse connection diagram to the board:

The board is customizable and validated before sale!

Specifications

Contents of delivery

Power regulator board for TDA1085 - 1pc.

Potentiometer with handle - 1 pc.

Switch - 1 pc.

Packing with instructions - 1pc.

Additional equipment

A set of wires with terminals - 5 pcs. +4 RUB

Reverse switch with wires on the terminals - 1 set +8 rub

Installing the board in the case with all switches and wires (only connect to the motor) +35 RUB

Benefits:

1. The transformer power circuit ensures safe and reliable operation.
2. All boards are tuned and tested before being sold.
3. The compact size of the board allows you to install it in any case.
4. High-quality installation of radioelements.
5. A factory-made PCB with a mask will provide protection against dust and corrosion.

Download description of the speed controller on the microcircuit TDA1085CG

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