Speed Control Angle Grinder Without Power Loss

Typical speed regulator circuit

This is how the governor board assembly looks like

The engine speed regulator is not just a variable resistor that steps down the voltage. An electronic control of the magnitude of the current is required, otherwise, with a drop in speed, the power will proportionally decrease, and, accordingly, the torque. In the end, a critically low voltage value will come, when, with the slightest resistance of the disk, the electric motor simply cannot return the shaft.
Therefore, even the simplest regulator must be calculated and executed in the form of a well-developed circuit.

And more advanced (and accordingly expensive) models are equipped with regulators based on an integrated circuit.

Integrated circuit of the regulator. (Most advanced option)

If we consider the electrical circuit of the angle grinder in principle, then it consists of a speed controller and a soft start module. Power tools equipped with advanced electronic systems are significantly more expensive than their simple counterparts. Therefore, not every home craftsman is able to purchase such a model. And without THESE electronic units, only the winding of the electric motor and the power key will remain.

The reliability of modern electronic components of the angle grinder exceeds the resource of the motor windings, therefore, you should not be afraid of purchasing a power tool, equipping with such devices. The limiter can only be the price of the product. over, users of inexpensive models without a regulator sooner or later come to install it on their own. The block can be purchased ready-made or made by yourself.

Angle grinder with speed controller: power tool capabilities

If the angle grinder is not equipped with a speed controller, can I install it myself??
Most angle grinders (angle grinder), among the common people of Bulgarians, have a speed controller.

The speed controller is located on the housing of the angle grinder

Consideration of the various adjustments should begin with an analysis of the electrical circuit of the angle grinder.

The simplest diagram of a grinding machine

advanced models automatically maintain rotational speed regardless of load, but tools with manual disc speed control are more common. If a button-type regulator is used on a drill or an electric screwdriver, then on an angle grinder such a regulation principle is not possible. Firstly, the features of the instrument suggest a different grip when working. Secondly, adjustment during operation is unacceptable, therefore, the speed value is set with the motor off.

Why generally adjust the rotational speed of an angle grinder?

  • When cutting metal of different thickness, the quality of work is highly dependent on the speed of rotation of the blade.
    When cutting hard and thick material, it is necessary to maintain the maximum rotation speed. When processing thin metal or soft metal (for example, aluminum), high speed will lead to melting of the edge or rapid blurring of the working surface of the disc;
  • Cutting and sawing stone and tiles at high speeds can be dangerous.
    In addition, the disk, which spins at high speeds, knocks out small pieces from the material, making the cutting surface chipped. over, for different types of stone, different speeds are selected. Some minerals are just processed at high speeds;
  • Grinding and polishing is basically impossible without speed control.
    Incorrectly setting the speed, you can ruin the surface, especially if it is a paintwork on a car or a material with a low melting point;
  • The use of discs of different diameters automatically implies the mandatory presence of a regulator.
    Changing the disc Ø115 mm to Ø230 mm, the rotation speed must be reduced by almost half. And holding an angle grinder with a 230 mm disc rotating at a speed of 10,000 rpm is almost impossible to hold in your hands;
  • Depending on the type of crowns used, stone and concrete surfaces are polished at different speeds. over, with a decrease in the rotational speed, the torque should NOT decrease;
  • When using diamond discs, it is necessary to reduce the number of revolutions, since their surface quickly breaks down from overheating.
    Of course, if your angle grinder only works as a pipe, angle and profile cutter, you will NOT need a speed controller. And with a universal and versatile application, the angle grinder is vital.

Making a speed controller with your own hands

Attempts to adapt a conventional dimmer to adjust the brightness of the lamp will do nothing. First, these devices are designed for a completely different load. Secondly, the principle of operation of the dimmer is NOT compatible with the control of the winding of the electric motor. Therefore, you have to mount a separate circuit, and figure out how to place it in the instrument case.

Homemade speed controller

The simplest thyristor speed controller can be easily made by yourself. This requires five radio elements, which are sold on any radio market.

Wiring diagram of a thyristor speed controller for your instrument

The compact design allows you to place the circuit in the case of an angle grinder without compromising ergonomics and reliability. However, this arrangement does not allow the torque to be maintained when the rpm drops. The option is suitable for reducing speed when cutting fine gestures, polishing work, processing soft metals.

If your angle grinder is used for stone processing, or disks larger than 180 mm can be installed on it, you need to assemble a more complex circuit, where the KR1182PM1 microcircuit is used as a control module, or its foreign analogue.

Electrocircuit of speed control using the KR1182PM1 microcircuit

This scheme controls the amperage at any speed, and minimizes the loss of torque when they are reduced. In addition, this scheme treats the engine more carefully, extending its resource.

The question of how to adjust the speed of the tool arises when it is stationary. For example, when using an angle grinder as a circular saw. In this case, the connection point (automatic machine or socket) is equipped with the regulator, and the speed is adjusted remotely.

Regardless of the method of execution, the speed controller of the angle grinder expands the capabilities of the tool and adds comfort when using it.

How to make a soft start and governor for an angle grinder

All budget options for an angle grinder have several disadvantages. First, there is no soft starter. This is a very important option. Surely all of you turned on this powerful power tool to the network, and when starting up, you watched how the incandescence of a light bulb, which is also connected to this network, falls.

This phenomenon occurs due to the fact that powerful electric motors consume huge currents at the moment of starting, due to which the mains voltage sags. This can damage the tool itself, especially those made in China with unreliable windings, which may one day burn out during start-up.

That is, the soft start system will protect both the network and the tool. In addition, at the time of launching the tool, a powerful kickback or push occurs, and in the case of a soft start system, this, of course, will not happen.

Secondly, there is no speed controller, which will allow you to work with a tool for a long time, and not load it.

The diagram below is from an industrial design:

It is introduced by the manufacturer into expensive devices.

You can connect to the circuit Not only an “angle grinder”, but, in principle, any devices. a drill, milling and turning machines. But taking into account the fact that the collector motor must be in the tool.

This will not work with induction motors. There needs a frequency converter.

So, you need to make a printed circuit board and start assembling.

You can download the board at the following link, which is at the bottom of the article.

A dual operational amplifier LM358 is used as a regulating element, which, using a VT1 transistor, controls the power triacs.

So, the power link in this circuit is a powerful BTA20-600 triac.

During operation, the triac will heat up, so a heat sink must be installed on it.

So that there are no questions about the fact that the motor, when starting, can consume current, which significantly exceed the maximum current of the triac, and the latter can simply burn out, remember that the circuit has a soft start, and inrush currents You can not take into account.

Surely everyone is familiar with the phenomenon of self-induction. This effect is observed when opening the circuit to which the inductive load is connected.

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It’s the same with this scheme. When the power supply to the motor is abruptly cut off, the self-induction current from it can burn the triac. And the snubber circuit dampens self-induction.

The resistor in this circuit has a resistance of 47 to 68 ohms, and a power of 1 to 2 watts. Film capacitor 400 V. In this version of self-induction as a side effect.

Resistor R2 provides current damping for the low voltage control circuit.

The circuit itself is to some extent both a load and a stabilizing link. Due to this, after the resistor, the power supply may not be stabilized. Although the network has the same circuits with an additional zener diode, it makes no sense to use it, since the voltage at the power supply pins of the operational amplifier is within normal limits.

Possible replacement options for low-power transistors can be seen in the following picture:

The printed circuit board that was mentioned earlier is only a soft starter board and contains components for speed control. This is done on purpose, since in any case, the regulator must be brought out using wires.

The regulator is tuned using a 100 kΩ multi-turn trimmer.

And the main adjustment is already using the resistor R5. It is worth saying that this kind of scheme will NOT allow adjustment from zero, only 30 to 100%.

If a more powerful regulator is needed, then it can be assembled according to the following scheme:

This scheme allows you to adjust the power almost from zero, but for an “angle grinder” it makes no sense.

First, the circuit must be checked for operability by connecting a 40-60 W 220 V light bulb as a load.

If everything is in order, then after disconnecting from the network, you immediately need to check the triac by touch. it must be cold.

Next, the board is connected to the “angle grinder” and starts.

If everything works fine. the “angle grinder” starts up smoothly and the speed is regulated. then it’s time to start the load tests.

Types of engines

Engines are different in characteristics. This means that one or another technique works at different frequencies of the shaft that starts the mechanism. The motor can be:

Speed Control Angle Grinder Without Power Loss
  • Single-phase,
  • Biphasic,
  • Three-phase.

Mostly three-phase electric motors are found in factories or large factories. At home, single-phase and two-phase are used. This electricity is enough to operate household appliances.

Description of the electric motor speed controller without power loss

Each of us at home has some kind of electrical appliance, which has been working in the house for more than one year. But over time, the power of the technique weakens and does NOT fulfill its intended lines. It is then worth paying attention to the insides of the equipment. Basically, problems arise with the electric motor, which is responsible for the functionality of the equipment. Then it is worth paying attention to the device, which regulates the engine power speed without reducing their power.

Power speed regulator

Work principles

The 220 V motor speed controller without power loss is used to maintain the initial set shaft speed. This is one of the basic principles of this device, which is called a frequency regulator.

With the help of it, the electrical appliance operates at the set engine speed and DOES NOT reduce it. Also, the motor speed controller affects the cooling and ventilation of the motor. With the help of power, the speed is set, which can be either raised or lowered.

The question of how to reduce the speed of a 220 V electric motor was asked by many people. But this procedure is pretty simple. One has only to change the frequency of the supply voltage, which will significantly reduce the performance of the motor shaft. You can also change the power supply of the motor by using its coils. Electricity control is closely related to the magnetic field and motor slip. For such actions, they mainly use an autotransformer, household regulators, which reduce the speed of this mechanism. But it is also worth remembering that engine power will decrease.

Shaft rotation

Engines are divided into:

  • Asynchronous,
  • Collector.

The speed controller of an asynchronous electric motor depends on the connection of current to the mechanism. The essence of the operation of an induction motor depends on the magnetic coils through which the frame passes. It pivots on sliding contacts. And when, when turning, it turns 180 degrees, then according to these contacts, the connection will flow in the opposite direction. Thus, the rotation will remain unchanged. But with this action, the desired effect will not be obtained. It will enter into force after a couple of dozen frames of this type are introduced into the mechanism.

The brushed motor is used very often. Its work is simple, since the transmitted current passes directly. because of this, the power of the electric motor turns is not lost, and the mechanism consumes less electricity.

The washing machine motor also needs power adjustment. For this, special boards were made, which cope with their work: the engine speed control board from the washing machine is multifunctional, since when it is applied, the voltage decreases, but the rotation power is not lost.

The circuit of this board has been verified. One has only to put bridges from diodes, picking up an optocoupler for the LED. In this case, you still need to put the triac on the radiator. Basically, engine tuning starts from 1000 rpm.

If you are not satisfied with the power regulator and lack its functionality, you can make or improve the mechanism. To do this, you need to take into account the current strength, which does not have to exceed 70 A, and the heat transfer during use. Therefore, you can install an ammeter to adjust the circuit. The frequency will be small and will be determined by the capacitor C2.

Next, it is worth adjusting the regulator and its frequency. When exiting, this pulse will go out through a push-pull transistor amplifier. You can also make 2 resistors, which will serve as an output for the computer’s cooling system. To prevent the circuit from burning out, a special lock is required, which will serve as a double current value. So this mechanism will work for a long time and in the right amount. Power control devices will provide your electrical appliances with many years of service at no extra cost.

Squirrel-cage and phase rotors

commonly used for rods in medium power motors, aluminum has a low density and high electrical conductivity.

To reduce the higher harmonics of the electromotive force (EMF) and to exclude the pulsation of the magnetic field, the rotor rods have a specially calculated angle of inclination with respect to the axis of rotation. If an electric motor of low power is used, then the grooves are closed structures that separate the rotor from the gap in order to increase the inductive component of the resistance.

The rotor in the form of a phase version or type is characterized by a winding, its ends are connected in the “star” type and connected to slip rings (on the shaft), along which graphite brushes slide. To eliminate eddy currents, the surface of the windings is covered with an oxide film. In addition, a resistor is added to the rotor winding circuit, which allows you to change the active resistance (R) of the rotor circuit to reduce the values ​​of inrush currents (Ip). Starting currents negatively affect the electrical and mechanical parts of the electric motor. Variable resistors used to regulate Ip:

  • Metal or stepped with manual switching.
  • Liquid (due to immersion to the depth of the electrodes).

Types and selection criteria

To select a regulator, you need to be guided by certain characteristics for a particular case. Among all the criteria, you can choose the following:

  • By the type of management. For motors of the collector type, regulators with a vector or scalar control system are used.
  • Power is the main parameter from which you need to build on.
  • By range U.
  • By frequency range. You need to choose a model that meets the user’s requirements for a particular case.
  • Other characteristics, which include the warranty, dimensions, equipment.

RPM setting methods

To prevent a negative effect during start-up, you need to reduce the speed of the 220 V or 380 V electric motor. There are several ways to achieve this goal:

  • Changing the R value of the rotor circuit.
  • Change of U in the stator winding.
  • Frequency change U.
  • Pole switching.

By changing the values ​​of U on the stator coil, mechanical or electrical control of the rotor speed is possible. In this case, a U regulator is used. Using this method allows it to be used only with a fan-like load (for example, a 220V fan speed regulator). For all other cases, three-phase automatic transformers are used, which make it possible to smoothly change the values ​​of U, or thyristor regulators.

Based on the formula for the dependence of the speed on the frequency of the supply U, it is possible to regulate the number of revolutions of the rotor. The frequency of the rotating magnetic field of the stator is calculated by the formula: Nst = 60 f / p (f is the frequency of the supply network current, p is the number of pole pairs). This method provides the possibility of smooth regulation of the rotational speed of the rotor part. To obtain a high efficiency, it is necessary to change the frequency and U. This method is optimal for squirrel-cage motors, since the power losses are minimal. There are two methods for changing the number of pole pairs:

  • In the stator (in the grooves), you need to put 2 windings with a different number of p.
  • The winding consists of two parts connected in parallel or in series.
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The main disadvantage of this method is the maintenance of the stepwise nature of the frequency change of an electric motor with a squirrel-cage rotor.

Principle of operation

When I flows through the stator winding, a magnetic flux (Ф) is created in each of them. These Φ are shifted 120 degrees to each other. The resulting Ф is rotating, creating an electromotive force (EMF) in aluminum or copper conductors. As a result of this, the starting magnetic moment of the electric motor is created, and the rotor begins to rotate. This process is also called slip (S) in some sources, which shows the difference in frequency n1 of the electromagnetic field of the starter, which becomes greater than the frequency obtained when the rotor rotates n2. It is calculated as a percentage and has the form: S = ((n1-n2) / n1) 100%.

The S value at the initial start of the electric motor is approximately 1, but with increasing n2 values ​​it becomes less. At this moment, I in the rotor decreases, therefore, the EMF becomes less than the nominal value. At idle, S is minimal, but with an increase in the moment of static interaction of the rotor and stator, this value reaches a critical value. If the inequality is fulfilled: S Sкр, then the motor works normally, however, if the value of Sкр is exceeded, it can “overturn”. Rollover causes unstable operation, but disappears over time.

General information

AC motors are widely used in many spheres of human life, namely, asynchronous-type models. The main purpose of the engine as an electrical machine is the transformation of electrical energy into mechanical energy. Asynchronous in translation means non-simultaneous, since the rotor speed differs from the frequency of the alternating voltage (U) in the stator. There are two types of asynchronous motors by type of power supply:

  • Single phase.
  • Three-phase.

Single-phase are used for domestic household needs, and three-phase are used in production. In three-phase asynchronous motors (hereinafter TAD), two types of rotors are used:

  • Closed;
  • Phase.

Closed ones make up about 95% of all motors used and have a significant power (from 250 W and more). The phase type is structurally different from blood pressure, but it is rarely used in comparison with the first. The rotor is a cylindrical steel figure, which is placed inside the stator, and a core is pressed onto its surface.

Design features

An asynchronous motor does not have pronounced poles, unlike a DC electric motor. The number of poles is determined by the number of coils in the windings of the stationary part (stator) and the connection method. In an asynchronous machine with 4 coils, a magnetic flux passes. The stator is made of sheets of special steel (electrical steel), which reduces eddy currents to zero, at which significant heating of the windings occurs. It leads to massive turn-to-turn closure.

The iron ore or the rotor core is pressed directly onto the shaft. There is a minimum air gap between the rotor and stator. The rotor winding is made in the form of a “squirrel cage” and is made of copper or aluminum rods.

In an electric motor with a power of up to 100 kW, aluminum is used, which has a low density. for pouring into the grooves of the rotor core. But despite such a device, engines of this type are heated. To solve this problem, forced cooling fans are used, which are mounted on the shaft. These motors are simple and reliable. However, the motors consume a large current when starting, 7 times the nominal. Because of this, they have a low starting torque, since most of the electricity energy goes to heating the windings.

Electric motors, in which there is an increased starting torque, differ from ordinary asynchronous ones in the design of the rotor. The rotor is made in the form of a double squirrel cage. These models are similar to phase types of rotor manufacturing. It consists of an inner and outer “squirrel cage”, and the outer one is the starting one and has a large active and small reactive R. The outer one has an insignificant active and high reactive R. When the rotation frequency increases, I switches to the inner cage and works in the form of a squirrel cage rotor.

Thyristor device

In this model, shown in diagram 1, 2 thyristors are used, connected in anti-parallel, although they can be replaced with one triac.

Scheme 1. Thyristor speed control of the collector motor without power loss.

This circuit performs regulation by opening or closing thyristors (triac) during a phase transition through neutral. For correct control of the collector motor, the following modification methods are used for circuit 1:

  • Installation of protective LRC-circuits consisting of capacitors, resistors and chokes.
  • Adding capacity at the inlet.
  • The use of thyristors or triacs, the current of which exceeds the rated value of the motor current in the range of 3.8 times.

This type of regulator has advantages and disadvantages. The former include low cost, low weight and dimensions. The second should include the following:

  • Application for low power motors;
  • There is noise and jerk of the motor;
  • When using a circuit on the triac, a constant U hits the motor.

This type of regulator is used in fans, air conditioners, washing machines and electric drills. It performs its functions perfectly, despite the shortcomings.

Transistor type

Another name for a transistor type regulator is an autotransformer or PWM regulator (Scheme 2). It modifies the U value on the basis of the pulse width modulation (PWM) principle using an output stage that uses IGBT transistors.

Scheme 2. transistor PWM speed controller.

The switching of transistors occurs at a high frequency, and due to this, the pulse width can be changed. Consequently, the U value will also change. The longer the pulse and the shorter the pause, the higher the U value and vice versa. The positive aspects of using this variety are as follows:

  • Low weight of the device with low dimensions.
  • Quite low price.
  • No noise at low rpm.
  • Low U value counting control (0.12 V).

The main disadvantage of the application is that the distance to the electric motor should not be more than 4 meters.

Use of 220 V motor speed controllers

When the electric motor is started, the current consumption is 7 times higher, which contributes to the premature failure of the electrical and mechanical parts of the motor. To prevent this, a motor speed controller should be used. There are many models of the factory plan, but in order to make such a device on your own, you need to know the principle of operation of the electric motor and how to regulate the rotor speed.

Crash test of the speed control board

The board for adjusting the revolutions of the collector electric motors on the TDA1085 microcircuit allows you to control the motors without losing power. A prerequisite for this is the presence of a tachometer (tachogenerator) on the electric motor, which allows the motor to provide feedback with the control board, namely the microcircuit. In simpler terms, so that it would be clear to everyone, something like the following happens. The motor rotates with a certain number of revolutions, and the installed tachometer on the shaft of the electric motor fixes these readings. If you start to load the engine, the shaft speed will naturally begin to drop, which will also fix the tachometer. Now let’s look further. The signal from this tachometer goes to the microcircuit, it sees this and gives a command to the power elements to add voltage to the electric motor. Thus, when you pressed on the shaft (giving a load), the board automatically added voltage and the power on this shaft increased. Conversely, let go of the motor shaft (remove the load from it), she saw this and reduced the voltage. Thus, the speed remains NOT low, and the moment of force (torque) remains constant. And most importantly, you can adjust the rotor speed in a wide range, which is very convenient in the use and design of various devices. Therefore, this product is called “Board for adjusting the speed of collector motors without power loss”.

But we saw one peculiarity that this board is applicable only for collector motors (with electric brushes). Of course, such motors are much less common in everyday life than asynchronous ones. But they are widely used in automatic washing machines. This is why this circuit was made. Especially for the electric motor from the washing machine automatic machine. Their power is quite decent, here are 200 to 800 watts. Which allows them to be widely used in everyday life.

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This product has already found wide application in the household of people and has widely covered people engaged in various hobbies and professional activities.

Answering this question. Where can you apply a washing machine motor? Some list was formed. Homemade wood lathe; Grinder; Electric drive for concrete mixer; sharpener; Electric drive for honey extractor; straw chopper; Homemade Pottery Wheel; Electric lawn mower; Wood splitter and many other things where mechanical rotation of any mechanisms or objects is necessary. And in all THESE cases, we are helped by this board “Adjusting the speed of electric motors with maintaining power on the TDA1085”.

Electric motor speed controller without power loss

The board for adjusting the revolutions of the collector electric motors on the TDA1085 microcircuit allows you to control the motors without losing power. A prerequisite for this is the presence of a tachometer (tachogenerator) on the electric motor, which allows the motor to provide feedback with the control board, namely the microcircuit. In simpler terms, so that it would be clear to everyone, something like the following happens. The motor rotates with a certain number of revolutions, and the installed tachometer on the shaft of the electric motor fixes these readings. If you start to load the engine, the shaft speed will naturally begin to drop, which will also fix the tachometer. Now let’s look further. The signal from this tachometer goes to the microcircuit, it sees this and gives a command to the power elements to add voltage to the electric motor. Thus, when you pressed on the shaft (giving a load), the board automatically added voltage and the power on this shaft increased. Conversely, let go of the motor shaft (remove the load from it), she saw this and reduced the voltage. Thus, the speed remains NOT low, and the moment of force (torque) is constant. And most importantly, you can adjust the rotor speed in a wide range, which is very convenient in the use and design of various devices. Therefore, this product is called “Board for adjusting the speed of collector motors without power loss”.

But we saw one peculiarity that this board is applicable only for collector motors (with electric brushes). Of course, such motors are much less common in everyday life than asynchronous ones. But they are widely used in automatic washing machines. This is why this circuit was made. Especially for the electric motor from the washing machine automatic machine. Their power is quite decent, here are 200 to 800 watts. Which allows them to be widely used in everyday life.

This product has already found wide application in the household of people and has widely covered people engaged in various hobbies and professional activities.

Answering this question. Where can you apply a washing machine motor? Some list was formed. Homemade wood lathe; Grinder; Electric drive for concrete mixer; sharpener; Electric drive for honey extractor; straw chopper; Homemade Pottery Wheel; Electric lawn mower; Wood splitter and many other things where mechanical rotation of any mechanisms or objects is necessary. And in all THESE cases, we are helped by this board “Adjusting the speed of electric motors with maintaining power on the TDA1085”.

Crash test of the speed control board

The board for adjusting the revolutions of the collector electric motors on the TDA1085 microcircuit allows you to control the motors without losing power. A prerequisite for this is the presence of a tachometer (tachogenerator) on the electric motor, which allows the motor to provide feedback with the adjustment board, namely the microcircuit. In simpler terms, so that it would be clear to everyone, something like the following happens. The motor rotates with a certain number of revolutions, and the installed tachometer on the shaft of the electric motor fixes these readings. If you start to load the engine, the shaft speed will naturally begin to drop, which will also fix the tachometer. Now let’s look further. The signal from this tachometer goes to the microcircuit, it sees this and gives a command to the power elements to add voltage to the electric motor. Thus, when you pressed on the shaft (giving a load), the board automatically added voltage and the power on this shaft increased. Conversely, let go of the motor shaft (remove the load from it), she saw this and reduced the voltage. Thus, the speed remains NOT low, and the moment of force (torque) is constant. And most importantly, you can adjust the rotor speed in a wide range, which is very convenient in the use and design of various devices. Therefore, this product is called “Board for adjusting the speed of collector motors without power loss”.

But we saw one peculiarity that this board is applicable only for collector motors (with electric brushes). Of course, such motors are much less common in everyday life than asynchronous ones. But they are widely used in automatic washing machines. This is why this circuit was made. Especially for the electric motor from the washing machine automatic machine. Their power is quite decent, here are 200 to 800 watts. Which allows them to be widely used in everyday life.

This product has already found wide application in the household of people and has widely covered people engaged in various hobbies and professional activities.

Answering this question. Where can you apply a washing machine motor? Some list was formed. Homemade wood lathe; Grinder; Electric drive for concrete mixer; sharpener; Electric drive for honey extractor; straw chopper; Homemade Pottery Wheel; Electric lawn mower; Wood splitter and many other things where mechanical rotation of any mechanisms or objects is necessary. And in all THESE cases, we are helped by this board “Adjusting the speed of electric motors with maintaining power on the TDA1085”.

How to choose an electric motor speed controller

To select the optimal device for controlling the speed of rotation of the shaft, it is important to take into account the indicators of the electric motor, as well as the features of their use.

Vector controllers are ideal for manifold models. Particular attention should be paid to the power of the solution. For safe operation, it must be slightly higher than the permissible parameter electric motor.

The voltage of electrical appliances must be within a wide range. Number of inputs and dimensions Must match motor specifications.

The principle of operation of the transformer speed controller

During start-up, the electric motor current strength Bends the windings of the power unit, while forming thermal energy. The input voltage is primarily fed to the speed controller, in which 220 V is rectified with the help of a diode. After that, the current flows to two capacitors, which act as a filter. At the output, a pulse-width modeled signal is generated, which is summed up to the windings of the electric motor and regulates the speed of rotation of the shaft.

Electric motor speed controller without power loss

For smooth control of the speed of rotation of the electric motor shaft, a special device has been created. a speed controller. It allows not only conveniently adjusting the speed of rotation of the shaft, which guarantees stable operation, but also avoids voltage interruptions and ensures a long service life of the equipment.

Features of the speed controller

The main task of the transformer speed controller is to organize smooth start and stop using PWM (Pulse Width Modulation). Such devices are included in many electrical appliances. They guarantee precise control and allow you to set the required speed.

There are also thyristor models, as well as devices that carry out frequency regulation.

Modern speed controllers are actively used in a wide variety of equipment:
heating,
Welding,
electric drives,
Electric oven,
washing and sewing machines,
Vacuum cleaner,
electric drives.

Features of the thyristor speed controller

Such devices are equipped with a pair of thyristors, which are connected in antiparallel. In this case, when the AC input voltage is applied, each thyristor allows only a half-wave. The control circuit controls the moment of opening and closing of thyristors at the moment of phase transition through zero. This allows you to cut a piece of tension at the end or beginning of the wave. This changes the rms voltage reading.

Most often, thyristor speed controllers are used to control the operation of various heating equipment. For electric motors, they are modified, depending on the inductive load:
thyristors are selected with an operating current, the value of which is several times higher than the motor current,
a capacitor is added at the output, which allows you to correct the shape of the voltage sine wave,
LRC circuits are used to protect power elements (resistors, capacitors or coils),
the minimum power is limited, which guarantees an easy start of the electric motor.

The main advantages of thyristor speed controllers are compact dimensions and reasonable price. As for the shortcomings, the main ones: only low-power motors can be adjusted to the rotation speed, jerk and noise are possible during operation.

Such controllers are often used to control fan speed in modern air conditioning systems.