The regulator’s function is to control the fan’s speed. The lower the ceiling fan speed, the lower the power consumption. Hence, the regulator serves to reduce power consumption.
Capacitive-based regulators are ideal for induction motor ceiling fans. The regulator controls the voltage supply, allowing the fan to rotate at the desired RPM. However, BLDC fans work differently.

In a BLDC fan, a microcontroller in the hardware’s circuit detects the input power supply and sets the fan speed appropriately. In contrast, the capacitive regulator controls the input supply. Therefore, all regulators do not control the input power supply similarly. Compared to regular ceiling fans, BLDC fans have stricter compliance requirements.
BLDC fans usually come with remote control options for speed control. Therefore, they come with warnings not to use external regulators. External regulators can cause the fan motor to draw more current, leading to overheating and motor failure.

Besides, an external regulator causes the fan to make more noise because the remote control is calibrated to coordinate with the motor and provide the ideal power to reduce noise.
Another drawback of external regulators with remote-controlled fans is that they can cause the fan to spin at abnormal speeds, especially if the regulator does not match the motor properly. Hence, it can lead to safety hazards. Besides, using external regulators with remote-controlled fans can render the warranty void.
However, major BLDC fan manufacturers like Atomberg and Orient Electric have recently released regulator fans. These fans have customized regulators different from those used for induction motor fans. The trade-off between the regular and customized regulators for BLDC fans is the Power Factor, which measures electricity wastage to our electricity grid.

Let us now answer the question, ‘Do BLDC fans require a regulator.’ It depends on the individual fan model. Generally, remote-controlled BLDC fans do not require a regulator because you can control the fan speed using the remote that coordinates with the microcontroller in the BLDC fan’s hardware. However, the top BLDC fan manufacturers have introduced regulator fans with customized operations.