Surely every beginner who first connected his life with radio-controlled electric models, after a thorough study of the filling, has a question. What are brushed and brushless motors? Which one is better to put on your radio-controlled electric model?
The brushed motors so often used to power radio controlled electric models have only two outgoing power wires. One of them is “+” the other is “-“. In turn, they are connected to the speed controller. Having disassembled the collector motor, you will always find there 2 curved magnets, a shaft together with an anchor, on which a copper thread (wire) is wound, where a gear is on one side of the shaft, and on the other side there is a collector assembled from plates, which include pure copper.
The principle of operation of the collector motor
Electric current (DC or direct current), flowing to the armature windings (depending on their number for each in turn) creates an electromagnetic field in them, which has a south pole on one side and a north pole on the other.
Many people know that if you take any two magnets and attach them poles of the same name to each other, then they will not come together for nothing, and if they are attached with opposite names, then they will stick so that it is not always possible to separate them.
So, this electromagnetic field that occurs in any of the armature windings, interacting with each of the poles of the stator magnets, drives (rotation) the armature itself. Further, the current passes through the collector and brushes to the next winding, and so sequentially, passing from one armature winding to another, the motor shaft rotates together with the armature, but only as long as voltage is applied to it.
In a standard collector motor, the armature has three poles (three windings) – this is done so that the engine does not “stick” in one position.
Cons of collector motors
By themselves, collector motors do a good job with their work, but this is only until the moment when it becomes necessary to get the highest possible speed from them at the output. It’s all about the very brushes mentioned above. Since they are always in close contact with the collector, as a result of high speeds, friction occurs at the place of their contact, which in the future will cause rapid wear of both and subsequently lead to a loss of effective electric power. engine. This is the most significant disadvantage of such motors, which nullifies all its positive qualities.
The principle of operation of a brushless motor
Here, the opposite is true, brushless motors do not have both brushes and a commutator. The magnets in them are located strictly around the shaft and act as a rotor. Windings that already have several magnetic poles are placed around it. A so-called sensor (sensor) is installed on the rotor of brushless motors, which will control its position and transmit this information to the processor that works in conjunction with the rotation speed controller (data exchange on the position of the rotor occurs more than 100 times per second). As a result, we get a smoother operation of the motor itself with maximum efficiency.
Brushless motors can be with a sensor (sensor) and without it. The absence of a sensor slightly reduces the efficiency of the motor, so their absence is unlikely to upset a beginner, but on the other hand, the price tag will pleasantly surprise you. It is easy to distinguish them from each other. For motors with a sensor, in addition to 3 thick power wires, there is also an additional loop of thin ones that go to the speed controller. It is not worth chasing motors with a sensor for both a beginner and an amateur, because only the pros will appreciate their potential, and the rest will simply overpay, and significantly.
Advantages of brushless motors
Almost no wear parts. Why “almost”, because the rotor shaft is mounted on bearings, which in turn tend to wear out, but their resource is extremely large, and their interchangeability is very simple. These motors are very reliable and efficient. A rotor position sensor is installed. On collector motors, the operation of brushes is always accompanied by sparking, which subsequently causes interference in the operation of radio equipment. So, for collectorless, as you already understood, these problems are excluded. No friction, no overheating, which is also a significant advantage. Compared to collector motors, they do not require additional maintenance during operation.
Cons of brushless motors
These motors have only one minus, this is the price. But if you look at it from the other side, and take into account the fact that the operation of brushless motors immediately frees the owner from such troubles as replacing springs, anchors, brushes, collectors, then you can easily give preference to the latter.