The engine speed controller is needed to perform smooth acceleration and braking. Such devices have become widespread in modern industry. Thanks to them, the speed of movement in the conveyor, on various devices, as well as when the fan rotates, is measured. Motors with 12 Volt performance are used in entire control systems and in cars.
Commutator motor type consists mainly of a rotor, a stator, as well as brushes and a tachogenerator.
Special frequency converters are used in the form of speed controllers for 220 V and 380 V electric motors . Such devices are classified as high-tech, they help to make a fundamental transformation of the current characteristics (signal shape, as well as frequency). They are equipped with powerful semiconductor transistors, as well as a pulse-width modulator. The entire process of operating the device occurs through the control of a special unit on a microcontroller. The change in speed in the rotation of the motor rotor occurs quite slowly.
It is for this reason that frequency converters are used in loaded devices. The slower the acceleration process occurs, the less load will be placed on the gearbox, as well as the conveyor. In all frequency generators you can find several degrees of protection: by load, current, voltage and other indicators.
Some models of frequency converters supply power from a single-phase voltage (it will reach 220 Volts) and create a three-phase voltage from it. This helps to connect an asynchronous motor at home without the use of particularly complex circuits and designs. In this case, the consumer will not lose power while working with such a device.
If we talk about regulator motors, then the revolutions needed are:
The circuits used to create frequency converters in an electric motor are widely used in most household devices. Such a system can be found in wireless power supplies, welding machines, phone chargers, power supplies for personal computers and laptops, voltage stabilizers, lamp ignition units for backlighting modern monitors, as well as LCD TVs.
You can make it completely yourself, but for this you will need to study all possible technical features of the device. By design, several types of main parts can be distinguished. Namely:
Just before starting the device, after applying a certain voltage to the windings, the process of rotating the engine begins with maximum power. It is this feature that will distinguish asynchronous devices from other types. On top of everything else, the load from the mechanisms that set the device in motion is added. Ultimately, at the initial stage of operation of the device, the power, as well as the current consumption, only increases to the maximum level.
At this time, the process of releasing the greatest amount of heat occurs. Overheating occurs in the windings, as well as in the wires. Using Partial Transformation will help prevent this from happening. If you install a soft start, then to the maximum speed mark (which can also be adjusted by equipment and may not be 1500 rpm, but only 1000), the engine will begin to accelerate not at the first moment of operation, but over the next 10 seconds (at the same time, every second the device will add 100-150 revolutions). At this time, the load on all mechanisms and wires begins to decrease several times.
You can completely independently create an electric motor speed controller of about 12 V. For this you should use switch of several positions at once, as well as a special wirewound resistor. With the help of the latter, the supply voltage level changes (and at the same time the rotation speed indicator). The same systems can be used to perform asynchronous movements, but they will be less effective.
Many years ago, mechanical regulators were widely used - they were built on the basis of gear drives or their variators. But such devices were considered not very reliable. Electronic means showed themselves several times better, since they were not so large and allowed for finer adjustment of the drive.
In order to create an electric motor rotation controller, it is worth using several devices at once, which can either be bought at any hardware store or removed from old inventory devices. To complete the adjustment process, you should turn on special variable resistor circuit. With its help, the process of changing the amplitude of the signal entering the resistor occurs.
To significantly improve the performance of even the simplest equipment, it is worth connecting microcontroller control to the engine speed controller circuit. To do this, you should choose a processor that has a suitable number of inputs and outputs, respectively: to connect sensors, buttons, and special electronic keys.
To carry out experiments you should use special microcontroller AtMega 128 is the easiest to use and widely used controller. In free use you can find a large number of schemes using it. In order for the device to perform the correct operation, a certain algorithm of actions should be written into it - responses to certain movements. For example, when the temperature reaches 60 degrees Celsius (the measurement will be noted on the graph of the device itself), the device should automatically turn off.
Now it’s worth talking about how you can adjust the speed in a brushed motor. Due to the fact that the overall speed of rotation of the motor can directly depend on the magnitude of the supplied voltage level, absolutely any control systems that can perform such a function are quite suitable for this.
It is worth listing several types of devices:
But at the same time, all such methods have a certain flaw. Together with the process of reducing speed, the overall power of the engine also decreases. Sometimes it can be stopped even by simply touching it with your hand. In some cases this may be quite normal, but for the most part it is considered a serious problem.
The most acceptable option would be to perform the function of adjusting the speed using tachogenerator applications.
It is most often installed at the factory. When the rotation speed of the motors deviates through the triacs in the motor, the already adjusted power supply will be transmitted, accompanying the desired rotation speed. If control of the rotation of the motor itself is built into such a container, then power will not be lost.
What does this look like in design? Most of all, it is the rheostat control of the rotation process, which is created based on the use of a semiconductor.
In the first case we will talk about variable resistance using a mechanical adjustment process. It will be connected in series to the commutator motor. The disadvantage in this case will be the additional release of some heat and an additional waste of the resource of the entire battery. During such an adjustment, a general loss of power occurs as the motor rotates. It is considered the most economical option. Not used for fairly powerful motors for the above reasons.
In the second case During the use of semiconductors, the process of controlling the motor occurs by applying a certain number of pulses. The circuit is capable of changing the duration of such pulses, which, in turn, will change the overall speed of rotation of the motor without loss of power.
If you do not want to manufacture equipment yourself, but want to buy a device that is completely ready for use, then you should pay special attention to the main parameters and characteristics, such as power, type of device control system, voltage in the device, frequency, and operating voltage . It would be best to calculate the general characteristics of the entire mechanism in which it is worth using a general motor voltage regulator. It is worth remembering that you need to make a comparison with the parameters of the frequency converter.
Many electronic circuits use active cooling systems with fans. Most often, their motors are controlled by a microcontroller or other specialized chip, and the rotation speed is controlled using PWM. This solution is characterized by not very smooth operation, can lead to unstable operation of the fan, and in addition, creates a lot of interference.
An analog fan speed controller has been developed for the needs of high-quality audio equipment. The circuit is useful in the construction of low-frequency amplifiers with an active cooling system and allows for smooth adjustment of fan speed depending on temperature. Performance and power depend mainly on the output transistor; tests were carried out with output currents up to 2 A, which allows you to connect even several large 12 V fans. Naturally, this device can also be used to control conventional DC motors, increasing the supply voltage if necessary. Although for very powerful engines you will have to use soft start systems tehprivod.su/katalog/ustroystva-plavnogo-puska
The circuit consists of two parts: a differential amplifier and a voltage stabilizer. The first part deals with temperature measurement and provides a voltage proportional to the temperature when it exceeds a set threshold. This voltage is the control voltage for the voltage stabilizer, the output of which controls the power supply to the fans.
The circuit diagram of the DC motor speed controller is shown in the figure. The basis is the comparator U2 (LM393), which works in this configuration as a regular operational amplifier. Its first part, U2A, works as a differential amplifier, whose operating conditions are determined by resistors R4-R5 (47k) and R6-R7 (220k). Capacitor C10 (22pF) improves the stability of the amplifier, and R12 (10k) pulls the comparator output to the power supply positive.
A voltage is applied to one of the inputs of the differential amplifier, which is generated through a divider consisting of R2 (6.8k), R3 (680 Ohms) and PR1 (500 Ohms), and is filtered using C4 (100nF). The second input of this amplifier receives voltage from the temperature sensor, which in this case is one of the connectors of transistor T1 (BD139), polarized with a small current using R1 (6.8k).
Capacitor C2 (100nF) was added to filter the voltage from the temperature sensor. The polarity of the sensor and reference voltage divider is set by regulator U1 (78L05) along with capacitors C1 (1000uF/16V), C3 (100nF) and C5 (47uF/25V), providing a stabilized voltage of 5 V.
The U2B comparator works as a classic error amplifier. It compares the voltage from the output of the differential amplifier with the output voltage using R10 (3.3k), R11 (47 ohms) and PR2 (200 ohms). The executive element of the stabilizer is transistor T2 (IRF5305), the base of which is controlled by the divider R8 (10k) and R9 (5.1k).
Capacitor C6 (1uF) and C7 (22pF) and C9 (10nF) improve feedback loop stability. Capacitor C8 (1000uF/16V) filters the output voltage, it has a significant impact on system stability. The output connector is AR2 (TB2), and the power connector is AR1 (TB2).
Thanks to the use of a low on-resistance output transistor, the circuit has a very low voltage dropout - about 50 mV at an output current of 1 A, which does not require a higher voltage power supply to drive 12 V fans.
In most cases, the popular operational amplifier LM358 can be used as U2, although the output parameters will be slightly worse.
Installation should begin with the installation of two jumpers, then all resistors and small ceramic capacitors should be installed.
In most cases, both of these elements will be mounted at the bottom of the board on legs that are bent at a 90-degree angle. This arrangement will allow them to be screwed directly to the radiator (be sure to use insulating gaskets).
Discuss the article ENGINE SPEED CONTROLLER 12 V
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.
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 ensure the accuracy of electrical control. This allows you to adjust the speed to the desired amount.
DC motor speed controller is used in many industrial and domestic applications. For example:
In order to select an effective regulator, it is necessary to take into account the characteristics of the device and its intended purpose.
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.
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.
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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 of engines. The circuits are powered separately; the key drivers require 12V power.
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.
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.
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.
Signals arriving at the system input form feedback. Let's take a closer look using a microcircuit.
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 with 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.
Based on the powerful triac BT138-600, you can assemble a circuit for an AC motor speed controller. This circuit is designed to regulate the rotation speed of electric motors of drilling machines, fans, vacuum cleaners, grinders, etc. The motor speed can be adjusted by changing the resistance of potentiometer P1. Parameter P1 determines the phase of the trigger pulse, which opens the triac. The circuit also performs a stabilization function, which maintains engine speed even under heavy load.
For example, when the motor of a drilling machine slows down due to increased metal resistance, the EMF of the motor also decreases. This leads to an increase in voltage in R2-P1 and C3 causing the triac to open for a longer time, and the speed increases accordingly.
The simplest and most popular method of adjusting the rotation speed of a DC motor is based on the use of pulse width modulation ( PWM or PWM ). In this case, the supply voltage is supplied to the motor in the form of pulses. The repetition rate of the pulses remains constant, but their duration can change - so the speed (power) also changes.
To generate a PWM signal, you can take a circuit based on the NE555 chip. The simplest circuit of a DC motor speed controller is shown in the figure:
Here VT1 is an n-type field-effect transistor capable of withstanding the maximum motor current at a given voltage and shaft load. VCC1 is from 5 to 16 V, VCC2 is greater than or equal to VCC1. The frequency of the PWM signal can be calculated using the formula:
F = 1.44/(R1*C1), [Hz]
Where R1 is in ohms, C1 is in farads.
With the values indicated in the diagram above, the frequency of the PWM signal will be equal to:
F = 1.44/(50000*0.0000001) = 290 Hz.
It is worth noting that even modern devices, including those with high control power, are based on precisely such circuits. Naturally, using more powerful elements that can withstand higher currents.
Adjusting the speed of electric motors in modern electronic technology is achieved not by changing the supply voltage, as was done before, but by supplying current pulses of different durations to the electric motor. PWM, which has recently become very popular, is used for these purposes ( pulse width modulated) regulators. The circuit is universal - it also controls the engine speed, the brightness of the lamps, and the current in the charger.
PWM regulator circuit
The above diagram works great, attached.
Without altering the circuit, the voltage can be raised to 16 volts. Place the transistor depending on the load power.
Can be assembled PWM regulator and according to this electrical circuit, with a conventional bipolar transistor:
And if necessary, instead of the composite transistor KT827, install a field-effect IRFZ44N, with resistor R1 - 47k. The polevik without a radiator does not heat up at a load of up to 7 amperes.
PWM controller operation
The timer on the NE555 chip monitors the voltage on capacitor C1, which is removed from the THR pin. As soon as it reaches the maximum, the internal transistor opens. Which shorts the DIS pin to ground. In this case, a logical zero appears at the OUT output. The capacitor begins to discharge through DIS and when the voltage on it becomes zero, 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: “R2->upper arm R1 ->D2”, and the discharge along the path: D1 -> lower arm R1 -> DIS. When we rotate 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. By changing the charge/discharge resistance ratio, we change the duty cycle. 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 use any diodes, capacitors of approximately the same value as in the diagram. Deviations within one order of magnitude do not significantly affect the operation of the device. At 4.7 nanofarads set in C1, for example, the frequency drops to 18 kHz, but it is almost inaudible.
If after assembling the circuit the key control transistor gets hot, then most likely it does not open completely. That is, there is a large voltage drop across the transistor (it is partially open) and current flows through it. As a result, a lot of power is dissipated for heating. It is advisable to parallel the circuit at the output with large capacitors, otherwise it will sing and be poorly regulated. To avoid whistling, select C1, the whistling often comes from it. In general, the scope of application is very wide; its use as a brightness regulator for high-power LED lamps, LED strips and spotlights will be especially promising, but more on that next time. This article was written with the support of ear, ur5rnp, stalker68.
