The key to the durability of any engine is its smooth operation. To solve this problem, collector power plants are used speed controllers with power control. These devices can be purchased or made by hand. The speed controller is a frequency converter based on a powerful transistor. It is necessary to invert the voltage, as well as to smoothly stop (start) the electric motor using a wide-pulse control of electrical devices or PWM.
Content
- Scope of regulators
- How the device works
- Selection recommendations
- DIY making
Scope of regulators
A simple example of such a converter is a voltage regulator often used in the home. However, in comparison with it, the speed controller is more functional. Frequency converters are widely used and are used in all electrical devices. Thanks to their use, not only precise control is ensured over engine operation,
but also savings in electrical energy is achieved, since the power plant consumes only the required power, and not the maximum.
You can buy an engine speed controller without loss of power to solve the following tasks:
- Control of the motor temperature without the use of additional controllers.
- Maintenance costs are reduced.
- Provides a smooth start.
- Electricity is saved.
The device is used in all household appliances, welding machines, etc.
How the device works
The device includes three main subsystems:
- Electric motor.
- Microcontroller control system with a converter block.
- Drive and related mechanisms.
After the electric motor has been started, the current in the circuit reaches its maximum values. Moreover, this process is repeated several times, which leads to the release of a large amount of heat. As a result, the life of the motor is reduced. The device used acts as a step inverter, providing double conversion of energy.
Depending on the applied voltage, the frequency regulator rectifies the current by means of a diode located at the input of the circuit. Then the current goes through additional filtering, thanks to several capacitors, and enters the microcircuit that forms the PWM. As a result of all these processes, the motor winding is not overloaded.
Selection recommendations
There are several characteristics to look out for when choosing a regulator:
-
Control type - vector and scalar control systems. The first type is more commonly used, but the second is more reliable. - Power - this indicator must correspond to the maximum allowable power of the protected device. If the power plant is low-voltage, then you should opt for a regulator with a higher power rating in comparison with the permissible one.
- Voltage - selected in accordance with the characteristics of the engine.
- Frequency range - should fully correspond to the tasks set, for example, 1000 Hz is quite enough for a hand-held milling machine.
All other characteristics (dimensions, warranty period, etc.) ) can be safely considered secondary. There are many brands on the market that produce high-quality and relatively inexpensive devices.
DIY making
If the device is planned to be used at home, then sometimes it makes no sense to buy a ready-made one. From a financial point of view, it is easier to make a speed control with maintaining power with your own hands. This will require only a few radio componentsthat can be easily purchased. The main element of the circuit is a VT138-600 type triac, and a potentiometer is used to control the speed (denoted by the letter P).
There are many schemes for creating a speed regulator, but the proposed one is the easiest to manufacture. The device assembled on its basis can be used to solve various tasks, for example, in the electric drive of a sewing machine or a table-top machine. The principle of operation of the circuit is extremely simple: when the rotation of the engine slows down, the indicator of its induction decreases, which leads to an increase in the voltage on C3, R 2 and P, followed by the opening of the thyristor.
Although the proposed scheme is simple, it allows solve a large number of tasks. If desired, you can assemble a more complex device - a thyristor controller with feedback. This is a profitable solution from the point of view of saving energy, but it requires a greater set of knowledge in the field of radio engineering, because almost all of them are based on microcircuits, for example, the TDA 1080.
