Types Of Brushless RC Motors: With their Applications


The Types Of Brushless RC Motors are discussed in this article. The brushless motors that RC cars make use of, are RC motors. RC motors are of two types- inner rotor in runners and outer rotor or out runners.

In brushless RC Motors, the electromagnets (poles) are fixed and the permanent magnets are on the spinning part of the engine. The permanent magnets of the in runner brushless motors are housed inside the electromagnets. In the out runner motor, permanent magnets and electromagnets are opposite to each other.

Types Of Brushless RC Motors- FAQs

How do I choose a brushless RC motor?

There are two types of RC motors as discussed above, the inrunners and outrunners. The factors on which a brushless RC motor’s efficiency depends are- speed, size, power etc. Here are the details-

Speed: KV number denotes RPM i.e. the speed of the motor. More the KV, the higher the speed. 

Size: For the right size, pick a motor that fits the RC car/ drone properly.

Power: The power (Watts), should be high. For power, check the Voltage of the motor pull denoted by Amps. It gives the right Electronic Speed Controller (ESC). 

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Types Of Brushless RC Motors
RC Car Brushless Motor; Image Credits: amazon.com

What’s the fastest brushless RC motor?

The US-based company Traxxas is probably the most famous name in the world of RC cars. They produce both electrically controlled and nitro radio cars, trucks, off-road vehicles, boats, and even drones.

The Traxxas X0-1 is a fast RTR RC electric car. It can reach 0 to 60-mph in just 2.3 seconds and in the long run, can reach 100-mph in 4.92 seconds. It is powered by a large electric brushless motor that provides high speed driving to help the car break all records. It is available as a kit car also.

Traxxas XO-1 | Fastest RC Car | 100 MPH RC Car | Traxxas
Traxxas X0-1 RC moror with car kit; Image credits: traxxas.com

What is the most powerful RC motor?

The MGM Losi 5-T brushless motor is regarded as the most powerful RC motor. The model comes with soldered battery, PC cables and motor connectors for providing very high power.

The additional features of MGM brushless RC motor are-

  • Five windings
  • PC connectivity for reading data from ESC
  • Mechanical air cooler inside the motor
The most powerful ESC + MOTOR combo for RC cars  - MGM Losi 5-T
MGM RC motor; Image Credits: mgm-controllers.com

How do you size a brushless motor?

Non-brush motors use a standard number scheme to define their body size and Kv ratio. For example: There is a 5055-3000Kv brushless outer rotor motor. We seperate the numbers as follows: [50] [55] – [3000].

[50] shows the motor’s diameter mm; (here -50mm)

[55] shows the motor’s length in mm; (here -55mm)

[3000] shows the Kv rating; (here- 3000Kv). The Kv rating is the ratio of a motor’s RPM (K) and voltage (v) with no load. E.g- a brushless motor of 3000 Kv powered by a 12V supply can produce 36,000 RPMs (3000×12).

Read more on….Types of brushless motor: with their applications

How do RC brushless motors work?

The main difference between a brushed and a brushless RC motor is the way they change currents in their coils. Brushed motors use brushes and commutators while brushless ones use electrical commutation.

Brushless RC motors need a controller that determines when to change the current direction in the wires on the basis of the relative position of the wires and the magnets. This is sometimes called brushless control and in the RC systems, this is known as brushless ESC (electronic speed control).

Why do Brushless RC motors have 3 wires?

Brushless RC motors have 3 wires unlike the brushed RC motors that contain 2 wires. Brushless motors are 3-phase systems that require more complex circuitry which controls the AC current needed to drive them.

An RC brushless motor consists of some three-wire coils that create electromagnetic forces. At any point of time, one wire is powered, one is grounded and one works as the sensor. The ESC switches current between the wires that creates push and pull and makes the rotor spin.

Can brushless motors work without ESC?

In BLDC, the DC to AC conversion is done electronically. To do that, electrical devices need to know what angle the motor remains at, so there is a sensor that feeds that information back to the controller.

The ESC( Electronic speed control) is in control of all of this. It switches the power at the correct time and keeps the motor rotating. This is considered a vital part of the motor, as it replaces the brushed DC motor’s commutator. There is no way to make the motor do anything useful without a brushless motor controller.

Brushless RC motor ESC (Electronic speed control) ; Image Credits: amazon.com

Can brushless motor have two wires?

Brushless motors having 3 wires last longer, rotate faster, and help batteries sustain. The ESC controller makes the rotor magnet spin. Without the ESC, it is not possible to construct a brushless RC motor.

If a brushless motor has only two wires, it will act as a one phase AC motor. Since brushless RC motors are three phase motors, they need two power controlling wires and an additional wire for controlling speed, direction and sending feedback. Some motors have up to 7-8 wires for higher phase systems.

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How is brushless motor ESC calculated?

The ESC is an electronic circuit for changing the speed of a vehicle, its direction, and to act as a flexible brake. Brushless ESCs enable 3 phase AC power such as variable frequency drive to make motors work.

We should choose the ESC higher than the amps the motor pulls. If it pulls 20 amps, the ESC should be higher than 20 amps. RC helicopters need ESC as high as 50%. For RC cars, the ESC is 30% above the amps. For maximum performance, efficiency and safety, we must take an ESC at least 10 amps higher than the RC motor rating.

Kaushikee Banerjee

I am an electronics enthusiast and currently devoted towards the field of Electronics and Communications . My interest lies in exploring the cutting edge technologies. I'm an enthusiastic learner and I tinker around with open-source electronics. LinkedIn ID- https://www.linkedin.com/in/kaushikee-banerjee-538321175

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