The two types of electric motors currently being used in the radio controlled boats hobby are the brushed motor and the brushless motor.
What are they, and which one is best? Good Questions...let's take a quick look at these two types of electric motors.
ELECTRIC
To begin, all electric motors have magnets and coils of wire (windings). You don't have to remember any of your high-school physics, but the basics are that a coil of wire moving in a magnetic field creates an electric current. When you have a varying current through a coil of wire it will move relative to the magnetic field...in other words, it goes round and round!
First is the brushed motor
Most electric radio controlled boats use a brushed motor. These brushed motors look somewhat like a small metal can with an axle sticking out of one end and battery leads on the other. Inside that 'can' are the commutator shaft, the armature, wires, carbon brushes, and magnets.
The carbon brushes press against a spinning commutator (a set of electrical contacts on the armature) causing friction. This contact forms an electrical circuit between the DC electrical source (battery) and the armature coil-windings. When voltage is applied through the battery leads to these brushes it causes the motor to spin and gives forward and reverse motion to the radio controlled boat.
The downside of this configuration is the inevitable friction puts extra strain on the motor, and the brushes wear down with use...therefore needing periodical replacement.
In addition, the windings are pretty heavy to rotate, and since they are in the middle of everything they have difficulty getting rid of waste heat being created. Not only that, but the brushes make imperfect contact with the commutator as currents and speeds increase. So, you can see that there are quite a few losses in this setup. In practice a brushed motor will rarely be more than about 65-70% efficient.
Now let's examine the brushless motor
The brushless motor is becoming increasingly popular in the radio controlled boats hobby. Why is that? Well, one of the appeals of a brushless motor is in the sheer power it can give to your electric radio controlled boat. Brushless motors, as you might guess, do not have brushes. In turn, they don't require frequent cleaning, and without the brushes there is less friction which results in less heat -- the biggest killer of motor performance.
Another appealing factor for brushless motors is that they can handle a much higher voltage than brushed motors. With an increased voltage supply, brushless motors can really help someone new to radio controlled boating race at blistering speeds!
How does the brushless motor work? In contrast to its 'brushed' counterpart, the brushless motor has a permanent magnet in the rotor or shaft. There are sensors that determine the direction and how fast the magnet turns in order to produce voltage. Unlike the carbon brushes of the brushed motor, these sensors do not touch the armature.
In this configuration, the permanent magnets rotate and the armature remains static...opposite of the brushed motor model. This eliminates the problem of how to transfer current to a moving armature. In this setup, the brush-system/commutator assembly is replaced by an electronic controller. This controller performs the same power distribution function you will find in a brushed motor, but instead uses a solid-state circuit instead of a commutator/brush system.
This setup eliminates friction, and therefore results in much greater efficiency and a huge increase in power - a brushless motor can be up to 300% more powerful than a brushed motor. Plus, gone is the issue of brush replacement!
There are definitely advantages to running with a brushless motors...the first one being the brushless motor requires less maintenance and can be more reliable. A brushless motor can, in most cases, provide more torque and more efficient power than a comparable brushed motor.
Even though the initial cost of a brushless system is higher, if you factor in the maintenance and other costs associated with a low turn, powerful brushed motor, the cost will very quickly justify itself.
Keep in mind, however, these motors are only just now becoming legal in some professional radio controlled racing circuits! That may or may not apply to your individual situation and/or needs.
So, there you have it. The decision is yours...brushed or brushless. Consider your individual needs and goals, as well as cost and choose from the many radio controlled boats the one that is right for you right now. The thing is, your skills and goals will change over time, and you can certainly have more than one boat...one for every occassion!!
Get out there and have Fun!!
Electric Radio Controlled Boats Motors - Brushed VS Brushless ELECTRIC
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