In the first place, it is probably worth mentioning that for three-phase asynchronous electric motors and single-phase collector motors, fundamentally different systems of speed control are used. For example, for asynchronous units, thyristor control circuits, most common in the collector, are not applicable.
- 1 Varieties of collector motors and their applications
- 2 Rheostatic regulators of revolutions of collector engines
- 3 Semiconductor regulators of revolutions of collector engines
4 Among the additional features are several major
- 4.1 1. Reverse
- 4.2 2. Brake
- 4.3 3.WEIGHT system
- 4.4 4. Optically tying
- 5 What are the conclusions?
Varieties of collector motors and their applications
According to the principle of their work divided into five main types, each of which can be bought without any problems.
By type of food:
- direct current;
- alternating current.
According to the type of principle of arousal:
- parallel excitation;
- sequential arousal;
- mixed arousal.
It is worth noting that in AC motors only
- conductive brushes.
An electric current passing through the commutated windings of the stator and rotor causes the appearance of an electromagnetic field, which, in turn, drives the rotor. Brushes applied to transfer current to the rotor windings. They are made of soft conductive material. In most cases, it is graphite or a mixture of graphite with copper.
If you change the direction of current flow in the stator or rotor, the motor will be reversed. Usually this is done with the rotor windings, thus avoiding the remagnetization of the cores. In the case of a change in current in both coils - the direction of rotation of the engine will remain the same.
The most widespread AC collector motors. There are several reasons for such popularity. These include the relative simplicity of their manufacture and management. Also important is their ability to operate from ac and from dc.
When connected to an AC power source, a change in the electromagnetic field will occur simultaneously in both motor windings (stator and rotor), which will not lead to a change in the direction of rotation engine For the reversal of such motors they make a reversal of the rotor winding.
Although their efficiency is somewhat lower than that of fellows, they are widely used in the mass of household appliances: meat grinders, fans, power tools. In addition, it is worth mentioning a separate channel of their use. We are talking about small-sized engines for light-engine models.
Among the modellers, they deserve universal recognition because of the low power consumption, which is very important because limited battery charge, and multifunctionality of their control systems. This fact dramatically reduces the weight and dimensions of the products. These systems are rarely made by hand, but this is more than covered by an abundance of various designs and modifications, factory devices. Although cheap is not a pleasure to call it.
For the same reasons, collector electric motors are also popular with many “Kulibins”.
Today are quite popular collector electric motors 220v from washing machines. However, not everyone is in a hurry to use them in their homemade designs. And it's not that people do not know how to connect such engines, but rather doubt their behavior under load and the possibility of adjusting the speed. If there is such an opportunity, then how will this affect their power? And there are many other issues related to further use and of a particularly practical nature.
There are many types of collector electric motors of all three excitation systems. As well as a variety of control schemes of their speed. There are quite a few factory-made regulators. And on the Internet you can find a large number of different self-made schemes. In the end, you will have to choose the best option for each case separately, based on your own skills, financial capabilities and parameters of the existing engine.
All the nuances in one article can not be described. Therefore, we will try to deal with this issue on the example the above type of enginesbased on their relative simplicity and widespread.
As for the issue of power, the standard electric motor from the washing machine, with a regular the number of revolutions (about 12,000 on average), you are unlikely to be able to stop or significantly reduce the speed rotation.
Ways engine speed control there is a mass. To do this, you can use:
- factory boards for adjusting the speed of household appliances (mixers or vacuum cleaners);
- buttons from power tools;
- household lighting controls.
In a word - any devices that regulate voltage. However, such a system has a very tangible flaw. With a decrease in speed, due to a decrease in the supply voltage, the output power of the engine drops sharply. So, already at 600 rpm, you can easily hand stop motor shaft. This nuance may not interfere with the work, for example, in the manufacture of the regulator of the fan speed 220v or low-power pumps. But in the manufacture of homemade machines, such a scheme is absolutely not applicable.
In such cases, you can apply a tachogenerator. In the electric motors mentioned, it is installed initially in the factory. Its function is to report the number of revolutions of the armature of the engine and transfer them to the control board, which will already set them at the required level, with the help of power triacs.
With such a motor speed regulator, power will not be lost even with a significant decrease in the rotor speed. There is a sufficient number of such schemes, and their production at home should not cause unnecessary problems and financial costs. Which of the proposed options, speed regulators to choose, depends only on you.
Separately, it is worth mentioning the small-size collector engines used in modeling. Their huge variety, including size, weight, maximum speed and power consumption, generate the corresponding number of their control systems. In this case, the number of functions assigned to the speed regulator increases significantly, and their combinations may vary significantly depending on the type of model on which to be used.
On model engines, as well as on household, and industrial, several variants of control systems are used.
Rheostatic regulators of revolutions of collector engines
The easiest option is to turn on the passive load in series with the motor. Such systems usually consist of a rheostat (variable resistor) and a servo drive that mechanically adjusts the resistance.
When connecting the load, excess electricity turns to heat. But such regulators are used only on cheap models, in which there are low-power motors, but the price is very important.
Due to unjustified heat losses, the battery life of the model is noticeably reduced. Do not improve the position and loss of the moving contacts of the rheostat. But the durability of the battery is one of the main criteria for the selection of engine speed control systems.
Separate trouble - unwanted overheating of the whole structurethat does not in the best way affect its durability and as a result, the need for forced heat removal. For serious models, such mechanical engine control systems have not been installed for a long time.
Semiconductor regulators of revolutions of collector engines
A healthy alternative to the aforementioned devices are semiconductor systems. They are powered by the engine pulses, and the speed control is achieved by changing their duration. This can significantly reduce the consumption of precious battery power. And on this option, perhaps, it is worth staying in more detail.
Due to the growing popularity of modeling, and as a result, and the demand for all kinds of automation for models, the number of offers on the market has increased dramatically. Now, it is not difficult to acquire speed controllers, in fact, under any engine. In addition, it is possible to buy options with advanced functionality - a reliable fan and other devices.
Among the additional features are several major
In some cases, the model requires reverse gear. Therefore, many regulators have the possibility of "polarity reversal" of the motor. Sometimes the reverse is carried out not at full capacity, because there is rarely a need for such a regime at full speed.
Often, on models there is a need not only in the rapid set of engine revolutions, but also in its stopping. Such systems are often used in automotive modeling. Braking is carried out by shorting the motor winding with a regulator. Sometimes make a "soft" brake. In this case, the shorting occurs in pulses, which allows you to smoothly reduce speed.
Installed in models with low voltage power. It is built into the secondary supply chain, which allows power the radio and servo drives with one battery, instead of installing an extension. Although this function is not related to engine management, it can save you from an extra headache.
4. Optically tying
It is used in voltage regulators. In such systems, by means of galvanic isolation, the power circuits and the power of the radio receiver are separated. This is done in order to protect very sensitive radio equipment from powerful impulse pickups from power circuits of the regulator and electric motor, and thus increase the stability of their work, which is very important.
What are the conclusions?
Of course, this is not all types of speed control for the above type of engines. And the engines themselves are also very much. In each case, a separately selected kit will be used with the appropriate characteristics, which can reduce energy consumption.
There is no universal answer to this question, but you can buy the product when you have the above information.