The regulator of turns of the electric motor: a principle of action

The regulator of turns of the electric motor is necessary forsmooth acceleration and braking. Such devices have been widely used in industry. With their help, the speed of the conveyor belts, the rotation of the fans, is changed. Engines of 12 volts are used in control systems and cars. All saw switches that change the speed of rotation of the fan of the stove in the machines. This is one of the types of regulators. Only it is not intended for a smooth start. Change of speed of rotation occurs stepwise.

Application of frequency converters

As regulators of revolutions of electric motors220V and 380V frequency inverters are used. These are high-tech electronic devices that allow you to radically change the current characteristics (waveform and frequency). They are based on high-power semiconductor transistors and pulse-width modulator. The entire operation of the device is controlled by a block on the microcontroller. The change in the rotor speed of the motor is smooth.

Therefore, frequency converters are used inloaded machinery. The slower the acceleration, the less load the conveyor or gearbox will experience. All frequency bands are equipped with several degrees of protection - in terms of current, load, voltage and other. Some models of frequency converters are powered by single-phase voltage (220 volts), making it three-phase. This allows you to connect asynchronous motors at home without using complex circuits. And the power will not be lost when working with such a device.

For what purposes are the regulators used

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

1. Significant energy savings. After all, not every engine requires a high speed of rotation of the motor - sometimes it can be reduced by 20-30%, and this will reduce the cost of electricity by half.
2. Protection mechanisms and electronic circuits. With the help of frequency converterscontrol temperature, pressure and many other parameters. If the engine works 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 simply turns off.
3. Soft start. There is no need to use additional electronic devices - all can be done by changing the settings of the frequency converter.
4. Reduction of maintenance costs. With the help of similar speed controllers for 220V motors, the risk of failure of the drive and individual mechanisms is reduced.

The scheme by which frequencyconverters, is widely distributed in many household appliances. Something like this can be found in uninterruptible power supplies, welding machines, voltage regulators, power supplies for computers, laptops, phone chargers, ignition lamps for modern LCD TVs and monitors.

How Rotation Controls Work

It is possible to make the regulator of revolutions of the electric motor, but for this purpose it is required to study all technical moments. Structurally, there are several main components, namely:

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

At the very beginning of work, after energizingwinding, the rotor of the engine rotates with maximum power. This feature distinguishes asynchronous machines from others. To this is added the load from the mechanism that is set in motion. As a result, at the initial stage, the power and current consumption increase to a maximum.

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

Homemade regulator

You can do the speed control yourself12V electric motor. This will require a switch to several positions and wire resistors. With the help of the latter, the supply voltage changes (and with it the rotational speed). 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 variable-speed drives. But they were not very reliable. Electronic tools are much better than themselves. After all, they are not so bulky and allow you to fine-tune the drive.

For the manufacture of the rotation controllerthe motor will require several electronic devices that can either be purchased from a store or removed from old inverter devices. Quite good results are shown by the simistor VT138-600 in the circuits of such electronic devices. To make the adjustment, you will need to include in the circuit a variable resistor. With it, changes the amplitude of the incoming signal to the triac.

Management system implementation

To improve the parameters of even the simplestdevice, you will need to include microcontroller control in the motor speed controller circuit. To do this, choose 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 easy to use. In the free access, you can find many schemes using this controller. Independently to find and apply them in practice is not difficult. In order for it to work correctly, you will need to write down an algorithm in it — responses to certain actions. For example, when the temperature reaches 60 degrees (measured on the radiator of the device) a power outage should occur.

Finally

If you decide not to make your own device,and to get ready, then pay attention to the basic parameters such as power, type of control system, operating voltage, frequency. It is advisable to calculate the characteristics of the mechanism in which it is planned to use a motor voltage regulator. And do not forget to compare with the parameters of the frequency converter.