What Is a Drone ESC?

ESC stands for Electronic Speed Controller, a device that manages the speed, direction, and braking of a drone’s motor. Acting as a bridge between the Drone battery and the Drone motor, the ESC receives control signals from the flight controller and regulates how much power is delivered to the motors.

There are two main categories of ESCs:

• Brushed ESC – Designed for simple DC brushed motors. It changes current direction to control motor rotation.
• Brushless ESC – Converts DC into three-phase AC for brushless motors, allowing precise control, higher efficiency, and smoother performance.

Today, almost all UAVs use brushless ESCs because they deliver higher power output and longer service life.

Functions of a Drone ESC

A drone ESC does much more than just speed regulation. Its primary functions include:

1. Motor Speed Control
   By receiving PWM (Pulse Width Modulation) signals from the flight controller, the ESC regulates voltage and adjusts motor RPM for stable flight.
2. Direction Control
   Brushed ESCs can reverse current to change the direction of motor rotation. Brushless ESCs achieve this by altering the order of phase signals.
3. Power Conversion
   Brushless ESCs convert DC input from the battery into three-phase AC output to run the motor efficiently.
4. Safety & Protection
   ESCs act as safeguards between motor and battery, preventing sudden surges of current that could otherwise cause overheating, component damage, or even in-flight hazards.

Types of Drone ESCs

ESCs can be classified based on structure, power supply, and control method.

1. Based on Structure

• Single ESC: One ESC controls one motor. A quadcopter requires four separate ESCs. Advantage: if one fails, it can be replaced individually.
• 4-in-1 ESC: Combines four ESCs into one compact board, reducing wiring clutter and saving space. Common in FPV drones and lightweight UAVs.

2. Based on Power Supply

• ESC with BEC (Battery Elimination Circuit): Supplies regulated power (5–6V) directly to the flight controller or receiver.
• OPTO ESC (without BEC): Requires an external power source for flight controller, but reduces electrical noise interference.

3. Based on Control Method

• Square Wave ESC: Uses PWM signals to control the motor. Affordable and widely used, but may cause torque ripple at higher speeds.
• Sine Wave ESC: Provides smoother rotation, reduces vibration, and improves stability.
• FOC (Field Oriented Control) ESC: The latest and most advanced type. It uses vector control with SVPWM technology for ultra-smooth torque, faster response, and higher efficiency. Perfect for professional UAV applications.

How to Choose the Right ESC

When selecting an ESC, always follow the order: Motor → ESC → Battery.

1. Current Rating
   The ESC current rating should always exceed the motor’s maximum draw by 10–20%.
   • Example: If your motor draws 26A at full throttle, select at least a 30A ESC.
2. Voltage Rating
   Match the ESC with your battery’s cell count (e.g., 2S, 4S, 6S). Never use a battery that exceeds the ESC’s maximum supported voltage.
3. Size & Weight
   Racing drones need small, lightweight ESCs for faster response. Large UAVs require bigger ESCs with better heat dissipation for stable performance.
4. PWM Frequency
   Higher PWM frequency = faster response and smoother control. Most modern ESCs support >500 Hz.

Bharath ESC (IBESC) – Built for Performance

At Bharath Components, our IBESC series ESCs are engineered to meet the growing demands of UAVs in both civilian and defense sectors.

Key Specifications of Bharath ESC (IBESC)

• Microcontroller: STM32F405
• Continuous Current: 40A
• Peak Current: 60A
• Maximum Voltage: 60V
• Drive Mode: FOC (Field Oriented Control)
• PWM Input: 3.3V / 5V compatible
• Communication: USB, CAN
• Operating Voltage: 6S battery support
• IP Rating: IP67 (dustproof & waterproof)
• Temperature Range: –40 °C to +85 °C

These features ensure smooth motor operation, long service life, and safe UAV performance under extreme conditions.

How to Connect an ESC to a Drone

1. Input Wires (thick red & black): Connect directly to the battery.
2. Output Wires (3-phase): Connect to the motor terminals.
3. Signal Wire (thin): Connect to the flight controller.

If the motor spins in the wrong direction, swap any two output wires.

How to Calibrate a Drone ESC

1. Switch on your transmitter and move throttle to maximum.
2. Connect the ESC to the battery.
3. Wait for a double beep, then lower throttle to minimum.
4. A long beep confirms calibration is complete.

Conclusion

An 40A Drone ESC (Electronic Speed Controller) is the heart of a drone’s propulsion system, balancing power between the motor, battery, and flight controller. Choosing the right ESC ensures smooth motor control, safety, and efficiency in UAV operations.

At Bharath Components, we provide advanced IBESC series ESCs designed for high reliability and performance. Whether you are building racing drones, agricultural UAVs, or defense-grade drones, our ESCs offer the power, durability, and safety you need.

Explore our range of drone ESCs and components at bharathcomponents.com.

FAQ

1. What is the function of ESC in drones?
It controls motor speed, direction, and braking, ensuring stable flight.

2. What is the difference between brushed and brushless ESC?
Brushed ESC controls DC motors, while brushless ESC converts DC to three-phase AC for efficient motor control.

3. Which is better: Single ESC or 4-in-1 ESC?
Single ESCs are easier to replace; 4-in-1 ESCs reduce wiring and save space.

4. What does BEC in ESC mean?
BEC stands for Battery Elimination Circuit, providing 5–6V power to the flight controller.

5. How do I select the right ESC?
Choose based on motor current, battery voltage, weight requirements, and PWM frequency.