Each of us has some kind of electrical appliance at home that has been working in the house for more than one year. But over time, the power of the technology weakens and does not fulfill its intended purpose. This is when you should pay attention to the insides of the equipment. Mostly problems arise with the electric motor, which is responsible for the functionality of the equipment. Then you should turn your attention to a device that regulates engine speed without reducing its power.

Types of engines

The speed control with power maintenance is an invention that will breathe new life into an electrical appliance, and it will work like a newly purchased product. But it is worth remembering that engines come in different formats and each has its own maximum performance.

The engines have different characteristics. This means that this or that technique operates at different speeds of the shaft that triggers the mechanism. The motor may be:

1. single-phase,
2. two-phase,
3. 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.

Power speed regulator

Work principles

A 220 V electric motor speed controller without loss of power 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 its help, the electrical device operates at the set engine speed and does not reduce it. The engine speed controller also affects the cooling and ventilation of the motor. With the help of power, the speed is set, which can be either raised or reduced.

Many people have asked the question of how to reduce the speed of a 220 V electric motor. But this procedure is quite 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 to the motor by activating its coils. Electrical control is closely related to the magnetic field and motor slip. For such actions, they mainly use an autotransformer and 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:

1. asynchronous,
2. collector

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

The commutator motor is used very often. Its operation is simple, since the passed current passes directly - because of this, the power of the electric motor is not lost, and the mechanism consumes less electricity.

Engine washing machine also needs power adjustment. For this purpose, special boards were made that cope with their job: the engine speed control board from a washing machine has multifunctional use, since its use reduces the voltage, but does not lose rotation power.

The circuit of this board has been verified. All you have to do is install diode bridges and select an optocoupler for the LED. In this case, you still need to put a triac on the radiator. Basically, engine adjustment starts at 1000 rpm.

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

Next, you should configure the regulator and its frequency. When outputting, this pulse will go out through a push-pull amplifier using transistors. You can also make 2 resistors that will serve as an output for the computer's cooling system. To prevent the circuit from burning out, a special blocker is required, which will serve as double the current value. So this mechanism will work for a long time and in the required volume. Power regulating devices will provide your electrical appliances with many years of service without special costs.

This homemade circuit can be used as a speed controller for a motor direct current 12 V with rated current up to 5 A or as a dimmer for 12 V halogen and LED lamps up to 50 W. Management is done 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 at a much higher cost. Here we present a more advanced version that uses a 7555 timer, a driver for bipolar transistors and a powerful field-effect 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.

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.

12V LED lamps, for example LED strips, you can also safely connect 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.

The 220V electric motor speed controller allows you to change the frequency of either an electric motor designed to operate from a 220 volt network.

Quite a popular speed controller for 220 volt electric motors alternating current is a thyristor circuit. A typical circuit is to connect an electric motor or fan to the anode circuit of the thyristor.

One important condition when using such regulators is reliable contact throughout the entire circuit. The same cannot be said about commutator electric motors, since their brush mechanism creates short-term breaks in the electrical circuit. This significantly affects the quality of the regulator.

Description of the operation of the speed controller circuit

Below scheme thyristor speed controller, specifically designed to change the rotation speed of the collector electric motors(electric drill, milling cutter, fan). The first thing to note is that the motor, together with the power thyristor VS2, is connected to one of the diagonals of the diode bridge VD3, while the other is supplied with mains voltage 220 volt.

In addition, this thyristor is controlled by fairly wide pulses, thanks to which short-term shutdowns of the active load, which characterize the operation of the commutator motor, do not affect the stable operation of this circuit.

To control the thyristor VS1 on the transistor VT1, a pulse generator is assembled. This generator is powered by a trapezoidal voltage created as a result of limiting the positive half-waves by a zener diode VD1 having a frequency of 100 Hz. Capacitor C1 is discharged through resistances R1, R2, R3. Resistor R1 controls the discharge rate of this capacitor.

When the capacitor reaches a voltage sufficient to open transistor VT1, a positive pulse is sent to the control terminal VS1. The thyristor opens and now a long control pulse appears at the control pin VS2. And already from this thyristor, the voltage, which actually affects the speed, is supplied to the engine.

The rotational speed of the electric motor is controlled by resistor R1. Since an inductive load is connected to circuit VS2, spontaneous unlocking of the thyristor is possible, even in the absence of a control signal. Therefore, to prevent this undesirable effect, a diode VD2 is added to the circuit, which is connected in parallel to the excitation winding L1 of the electric motor.

Parts of the fan and electric motor speed controller

Zener diode - can be replaced with another one with a stabilization voltage in the region of 27 - 36V. Thyristors VS1 - any low-power with a direct voltage of more than 100 volts, VS2 - it is possible to supply KU201K, KU201L, KU202M. Diode VD2 - with a reverse voltage of at least 400 volts and a forward current of more than 0.3A. Capacitor C1 – KM-6.

Setting the speed controller

When setting up the regulator circuit, it is advisable to use a strobe, which allows either a pointer voltmeter for alternating current, which is connected in parallel with the engine.

By rotating the knob of resistor R1, the voltage range is determined. By selecting resistance R3, this range is set in the region from 90 to 220 volts. If the fan motor is unstable at minimum speed, then it is necessary to slightly reduce the resistance R2.

Any modern power tool or household appliance uses a commutator motor. This is due to their versatility, i.e. the ability to work from both alternating and DC voltage. Another advantage is the efficient starting torque.

However, the high speed of the commutator motor does not suit all users. For a smooth start and the ability to change the speed of rotation, a regulator was invented, which is quite possible to make with your own hands.

Operating principle and types of commutator motors

Each electric motor consists of a commutator, 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, they can all be divided into 2 groups: standard and modified products.

Standard device

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

Thus, the speed of the commutator motor is adjusted. In most cases, a similar scheme is used in foreign household vacuum cleaners. However, you should know 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.

Changed schemes

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

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

Rheostatic ones are effective in changing the number of revolutions of the commutator motor. High efficiency is due to power transistors, which take away part of the voltage. Thus, the current flow is reduced and the motor works with less effort.

Video: speed control device with power maintenance

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

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

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 operate effectively, it is necessary that there be a voltage of 12V at the gate. Therefore, the electrical circuit and the supply voltage itself must correspond to this range.

Overview of typical circuits

You can regulate the rotation of the low-power electric motor shaft using serial connection no power resistor. However, this option has very low efficiency and the inability to smoothly change speed. To avoid such a nuisance, you should consider several regulator circuits that are used most often.

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 when running at low speeds.

The second option is similar to the first. The only difference is that it is used as a master oscillator operational amplifier. This component has a frequency of 500 Hz and produces triangular-shaped pulses. Adjustment is also carried out using a variable resistor.

How to make it yourself

If you don’t want to spend money on purchasing a ready-made device, you can make it yourself. This way, you can not only save money, but also gain useful experience. So, for making thyristor regulator required:

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

As can be seen from the diagram, the regulator controls only 1 half-cycle. However, for testing performance on a regular soldering iron, this will be quite enough.

If you don’t have enough knowledge to decipher the diagram, you can familiarize yourself with the text version:

The use of regulators allows for more economical use of electric motors. In certain situations, such a device can be made independently. However, for more serious purposes (for example, monitoring 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 electric motor is necessary for smooth acceleration and braking. Such devices are widely used in industry. With their help, the rotation speed of the fans is changed. 12 Volt motors are used in control systems and automobiles. Everyone has seen the switches that change the rotation speed of the stove fan in cars. This is one of the types of regulators. It's just not designed to run smoothly. The rotation speed changes in steps.

Application of frequency converters

Frequency converters are used as speed regulators and 380V. These are high-tech electronic devices that allow you to radically change the characteristics of the current (signal shape and frequency). They are based on powerful semiconductor transistors and a pulse width modulator. All operation of the device is controlled by a microcontroller unit. The rotation speed of the engine rotor changes smoothly.

Therefore, they are used in loaded mechanisms. The slower the acceleration, the less load the conveyor or gearbox will experience. All frequency generators are equipped with several degrees of protection - for current, load, voltage and others. Some models of frequency converters are powered from single-phase and turn it into three-phase. This allows you to connect asynchronous motors at home without using complex circuits. And there will be no loss of power when working with such a device.

For what purposes are regulators used?

In the case of asynchronous motors, speed controllers are needed for:

1. Significant energy savings. After all, not every mechanism requires a high motor rotation speed - sometimes it can be reduced by 20-30%, and this will reduce energy costs by half.
2. Protection of mechanisms and electronic circuits. Using frequency converters, you can control temperature, pressure and many other parameters. If the engine operates as a pump drive, then a pressure sensor must be installed in the container into which it pumps air or liquid. And when the maximum value is reached, the motor will simply turn off.
3. Performing a soft start. There is no need to use additional electronic devices - everything can be done with setting changes frequency converter.
4. Reducing costs for Maintenance . With the help of such speed controllers for 220V electric motors, the risk of failure of the drive and individual mechanisms is reduced.

The circuit according to which frequency converters are built is widespread in many household appliances. Something similar can be found in the sources uninterruptible power supply, welding machines, voltage stabilizers, power supplies for computers, laptops, phone chargers, ignition units for backlight lamps of modern LCD TVs and monitors.

How do rotary controls work?

You can make an electric motor speed controller with your own hands, but to do this you will need to study all the technical aspects. Structurally, several main components can be distinguished, namely:

1. Electric motor.
2. Microcontroller control system and converter unit.
3. Drive and mechanisms associated with it.

At the very beginning of operation, after voltage is applied to the windings, the motor rotor rotates with maximum power. It is this feature that distinguishes asynchronous machines from others. To this is added the load from the mechanism that is driven. As a result, at the initial stage, power and current consumption increase to a maximum.

A lot of heat is generated. Both the windings and wires overheat. Using a frequency converter will help get rid of this. If you install smooth start, then to the maximum speed (which is also regulated by the device and may not be 1500 rpm, but only 1000), the engine will not accelerate immediately, but over 10 seconds (increase by 100-150 rpm every second). At the same time, the load on all mechanisms and wires will decrease significantly.

Homemade regulator

You can make your own speed controller for a 12V electric motor. This will require a multi-position switch and wirewound resistors. With the help of the latter, the supply voltage (and with it the rotation speed) changes. Similar systems can be used for asynchronous motors, but they are less efficient. Many years ago, mechanical regulators were widely used - based on gear drives or variators. But they were not very reliable. Electronic means perform much better. After all, they are not so bulky and allow you to fine-tune the drive.

To make an electric motor rotation controller you will need several electronic devices, which can either be purchased in a store or removed from old inverter devices. The VT138-600 triac shows good results in the circuits of such electronic devices. To make the adjustment, you will need to include in the circuit variable resistor. With its help, the amplitude of the signal entering the triac changes.

Implementation of a management system

To improve the parameters of even the most simple device, you will need to include microcontroller control in the electric motor speed controller circuit. To do this, you need to select a processor with a suitable number of inputs and outputs - for connecting sensors, buttons, electronic keys. For experiments, you can use the AtMega128 microcontroller - the most popular and easiest to use. You can find many schemes using this controller in the public domain. Finding them yourself and applying them in practice is not difficult. In order for it to work correctly, you will need to write an algorithm into it - responses to certain actions. For example, when the temperature reaches 60 degrees (measured on the radiator of the device), the power should be turned off.

Finally

If you decide not to make a device yourself, but to purchase a ready-made one, then pay attention to the main parameters, such as power, type of control system, operating voltage, frequencies. It is advisable to calculate the characteristics of the mechanism in which it is planned to use the motor voltage regulator. And don’t forget to compare it with the parameters of the frequency converter.