Any modern power tool or household appliance uses a collector motor. This is due to their versatility, that is, the ability to work as a variable, and from constant voltage. Another advantage is the effective starting torque.
However, the high speed of the collector motor does not suit all users. A regulator was invented for smooth start-up and the ability to change the speed, which is quite possible to make with your own hands.
The principle of operation and types of collector motors
Each electric motor consists of a collector, stator, rotor and brushes. The principle of its operation is quite simple:
- Current is supplied to the stator and rotor, connected to each other.
- A magnetic field is formed.
- Due to the influence of magnetic voltage, the rotor begins to rotate.
- Brushes (they are usually made of graphite) transmit voltage to the rotor.
- When changing the direction of current in the stator or rotor, the shaft rotates in the other direction.
In addition to the standard device also exist:
- Serial excitation motors - have greater resistance to overload (most often used in household appliances).
- Products of parallel excitation - have more turns and low resistance.
- Single-phase motors - ease of manufacture and a wide range of applications, but low efficiency.
Regulator device
There are many schemes of such devices in the world. However, all of them can be divided into 2 groups: standard and modified products.
Standard device
Typical products are easy to manufacture idinistor, good reliability when changing engine speed. Usually, such models are based on thyristor regulators. The principle of operation of such schemes is quite simple:
- The charge goes to the capacitor.
- Through the variable resistor is the breakdown voltage Dinistor.
- Then he "breaks through".
- The triac "opens", which is responsible for the load.
- The higher the voltage, the more often the "triac" will open.
So, the speed of the collector motor is regulated. In most cases, this scheme is used in foreign household vacuum cleaners. However, you should know, that such a speed regulator has no feedback. Therefore, when changing the load will have to adjust the speed of the motor.
Changed schemes
Of course, the standard device suits many fans of speed regulators to "dig" in electronics. However, without the progress and improvement of products, we would still be living in the Stone Age. Therefore, more interesting schemes are constantly being invented, which are gladly used by many manufacturers.
Rheostatic and integrated regulators are most often used. As the name implies, the first option is based on the rheostat circuit. In the second case, an integrated timer is used.
Rheostats are efficient in changing the speed of the collector motor. High efficiency is due to power transistors, which take away part of the voltage. So, current flow is reduced and the motor runs with less diligence.
Video: power control device with power maintenance
The main disadvantage of this scheme is the large amount of heat, that stands out. Therefore for uninterrupted work, the regulator must be constantly cooled. Moreover, the cooling of the device must be intensive.
Another approach is implemented in the integrated controller, where the integrated timer is responsible for the load. Usually, such circuits use transistors of almost any name. It has to do with that, that contains a chip, which has large values of output current.
If the load is less 0,1 amperes, then all the voltage goes directly to the chip bypassing the transistors. However, for the regulator to work effectively, it is necessary, that on a gate there was a voltage of 12B. Therefore, the electrical circuit and the voltage of the power supply itself must correspond to this range.
Overview of typical schemes
You can adjust the rotation of the shaft of the low power motor by connecting the power resistor in series with no. However, this option has a very low efficiency and no possibility of smooth change of speed. To avoid such trouble, several controller circuits should be considered, which are used most often.
Features of the first option:
- The PWM transistor has a sawtooth voltage generator with frequency 150 Hz.
- The operational amplifier acts as a comparator.
- A variable resistor is used to change the speed, which controls the duration of the pulses.
As you know, PWM has a constant pulse amplitude. in addition, the amplitude is identical to the supply voltage. so, the motor will not stop, even working at low speeds.
The second option is similar to the first. The only difference, that the operational amplifier is used as the master generator. This component has a frequency 500 Hz and generates pulses, having a triangular shape. Adjustment is carried out by a variable resistor.
How to make your own hands
If you do not want to spend on a ready-made device, it can be made yourself. So, you can not only save money, but also gain useful experience. so, for the manufacture of a thyristor regulator required:
- soldering iron (to check the efficiency);
- wire;
- thyristor, capacitors and resistors;
- scheme.
As can be seen from the diagram, the regulator is controlled only 1 half-life. However, this will be enough to test the performance of a conventional soldering iron.
If the knowledge to decipher the scheme is not enough, you can read the text version:
- Power from the mains goes to the capacitor.
- The capacitor receives a full charge and starts working.
- The load is transferred to the lower cable and resistors.
- The thyristor electrode is connected to the positive contact of the capacitor.
- One sufficient voltage charge
- The second semiconductor opens.
- The thyristor passes the load through itself, obtained from the capacitor.
- The capacitor is discharged and repeats the half-life.
The use of regulators allows more economical use of electric motors. In certain situations, such a device can be made yourself. However, for more serious purposes (example, control of heating equipment) it is better to buy a ready-made model. Good, there is a wide choice of such products on the market, and the price is quite democratic.