There are quite a few valid reasons for this, one main reason is the torque provided by these motors are very high which is very important to gain/loose thrust rapidly to take off or land down a drone. That is the BLDC motors, but why? Why do they use a BLDC motor which is a bit expensive compared to DC Motors? There are many types of cool drones out there from Quad copter to helicopters and gliders everything has one hardware in common. Why do Drones and other Multi-copters use BLDC Motors? This method is used in our motor and is common for drones and other flying projects. The second method is by using the back EMF generated by the coils when the magnets cross them, this required not additional hardware or wires the phase wire itself is used as a feedback to check for back EMF. The hall sensor will detect the magnet and send the information to ESC this type of motor is called a Sensord BLDC motor and is used in Electric vehicles. This information can be acquired in two ways one is by placing hall sensor inside the motor. That is the ESC has to know the position and pole of the magnets in the rotor so as to energise the stator according. Sensor and Sensorless BLDC Motor: For a BLDC motor to rotate without any jerk a feedback is required. Note: There is another type of motor called the coreless BLDC motors which are also used for pocket Drones, they have a different working principle but for now let’s skip it for the sake of this tutorial. The one that we are using here is also an out runner type. Also the out runner motors tend to give more torque than in runner types, hence it becomes an ideal choice in EV and Drones. Out runner motors are very advantages in Electric bikes since the outer casing (the one that rotates) itself is made into a Rim for the tyres and hence a coupling mechanism is avoided. While out runner BLDC motors are just the opposite, the Outer casing of the motor rotates along with the shaft while the coil inside stays fixed. That is the shaft inside the motor rotates while casing remains fixed. In-runner and Out-Runner BLDC motor: In runner BLDC Motors work like any other motor. There are many types of BLDC motors available, let’s take look at the most common classifications. We will learn more about ESC later in this article. The speed of the motor depends on how fast the coil is energised and direction of motor depends on in which order the coils are energised.
Then the next two wires are energised by the ESC, this process is continued to make the motor rotate. During this process the coil inside the motor is energised and hence the magnets on the rotor align itself to the energised coil. At any given time only two Phase of the motor will be powered, so that current enters through one phase and leaves through other. The Electronic speed controller (ESC) converts the DC voltage from the battery in to pulses and provides it to the 3 wires of the Motor. Yes, although BLDC motors are considered to be DC motors, they work with the help of Pulsed waves.
Use of BLDC motors in electric vehicles is previously explained in detail. Unlike other motors, the BLDC motors have three wires coming out of them and each wire forms its own phase thus given us a three phase Motor. BLDC Motor stands for Brush Less DC motor, it is commonly used in ceiling fans and electric vehicles due to its smooth operation.