Ahsan posted on May 01, 2010 20:08
Introduction:
I have been flying R/C models on and off for about 5 years now and over the course of my flying career I decided to start flying electric powered aircraft exclusively around mid-to-late 2007. Since then I have found various techniques through trial and error that seem to work well for converting models into electric power.Unlike Nitro and Gas power, electric power can be a little tricky, especially if you have just started getting into electrics. In this article I will be covering the very basics of electric power which includes the basics of Brushless & Brushed motors. Their will be additional articles that I will be posting later that discus these issues in depth which include battery and battery charging, Motor KV, Speed controller programming, and power to weight conversions between nitro engines and watts (electric engines).
Electric Motors Brushless & Brushed:
The very first thing you should know about getting into electrics is the difference between brushed and brushless motors. If you have ever seen one of those silvery brushed aluminum can motors that are in toys from Wal-Mart/Toys-r-Us you have seen a brushed motor. These motors typically have a red and black wire coming out them and you can power them simply by supplying electricity to the motor. Brushed motors have been around for quite a while and the overwhelming majority of R/C aircraft/cars/boats that are not made for the hobby grade are brushed motors. For the most part, these motors work fine, however, for modelers in the hobby brushed motors simply don’t offer the performance or the longevity of brushless motors.
Brushless motors have been around in industrial use since the 1970’s but only started appearing for R/C models in the late 1990’s. The main difference between a brushless motor and a brushless motor is that brushless motors are 3 phase motors and REQUIRE a BRUSHLESS speed controller to operate; they usually have 3 wires coming out of the motor and can’t “run” by plugging it directly to a battery. Structurally, brushless motors do not have wire brushes touching the “rotor” (this is a shaft with magnets that powers the motor” and thus have less friction when compared to brushed motors which use a commutator and brushes to power the motor. Since their introduction almost 10 years, brushless motors are now the dominant way to power R/C aircraft and many manufactures have started to include them with their entry level RTF (Ready-to-Fly) packages. If you are thinking about starting off with a ready to fly model check to see if it is brushless powered or brushed as this will greatly affect how long you can fly and the type of performance you can expect. The same is true if you are planning on setting your own ARF/KIT, make sure you understand the difference between these 2 power systems.
Below is a small bulleted list that covers the difference between the two:
- Brushed Motors are cheaper and are generally found in toys and a few entry level R/C RTF planes/helis
- Brushed Motors need a Brushed ESC, they can not run on Brushless ESC (electronic speed control)
- Brushed Motors have 2 wires coming out of the can and require maintenance of their brushes
- Brushless Motors are bit more expensive but offer more power and longer flight times than similar weight/size brushed motors
- Brushless Motors need Brushless ESCs can not use Brushed ESCs
- Brushless Motors have 3 wires coming out of them and generally do not require any maintenance aside from changing their bearings (which is required for both brushed & brushless motors)