Understanding RC Electric Motors

RC Motors

RC Motors are one of the main things in an RC machine. As you might have already guessed, motors are essential because they are used to rotate the wheels or propellers of the RC vehicle. Without them, your RC vehicle won’t run. So it is important to understand how the motors work, what type of motors are available etc.

 

Motor Types

RC motors come in two main categories. Brushed and Brushless motors. Brushed motors are in use for the longest time while brushless motors are the newer version with a lot more benefits. But obviously nothing is perfect so they have their disadvantages as well.

 

Brushed Motors

Brushed 540 Motor

Brushed motors are also sometimes referred as canned motors. There are other parts of the motor but we will stick to the main ones for the sake of simplicity. The main parts of a brushed motor are the fixed magnets, brushes and armature.

The armature consists of electromagnets (material that behaves like a magnet when current passes through it) and is surrounded by fixed magnets. The brushes are used to provide current to the armature. When the current is provided, the armature starts moving and your motors starts rotating.

Now with the passage of time, brushes wear off so it’s vital to replace them. They also need maintenance and cleaning for proper and long lasting function. And on top of that, they provide extra resistance and heat both of which are bad for the motor efficiency.

 

Brushless Motors

Brushless Motor

Brushless motors are the opposites of the brushed motors because in these the electromagnets stay stationary while magnets rotate. This essentially removes the requirement of brushes which makes this motor a lot more efficient. There is no more heat, resistance, maintenance and, therefore, replacement.

Brushless motors have two more types

Inrunners: These type of brushless motors have the rotating magnets inside the electromagnets. In other words, magnets are surrounded by electromagnets. These usually have a high speed but low torque.

Brushless Inrunner Motor

Outrunners: These are the opposite of inrunners. In these brushless motors, the electromagnets are surrounded by the rotating magnets. Hence the name, outrunners. These usually have low speed but high torque.

 

Brushless Outrunner motor

How to differentiate between a brushed and brushless motor

Now that you know what the two main types of motor are, it’s time to differentiate them. Firstly, you should see the pack or ask the shopkeeper which is quite easy. But usually a brushed motor will have 2 wires coming out of it and will probably have 2 holes for ventilation. A brushless motor will be completely sealed and there will be 3 wires coming out of it.

 

How to choose a proper motor

This is a huge topic itself but we will try to cover the basics of it.

The motors usually have a few numbers associated with them. The “max load” tells you how much current the motor can draw without damaging itself. The “no load current” usually tells you the amount of current the motor will consume without any load at a specific volt. The “RPM” or “kv” tells you how much the motor will rotate per given volts. The “voltage” or “No. of cells” indicates the type of battery required for the motor.

Some motors will provide more information like the rating of an ESC and internal resistance. You should be familiar with all of these and you should know what these mean to make sure that you get the right ratings of motor, ESC and batteries. You just need to find the right balance for your RC machine depending on the components used in it.

 

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