In the sweltering summer, industrial energy-saving fans play an indispensable role in our lives. However, after a period of use, these fans may encounter malfunctions, most notably a decrease in the ceiling fan's rotation speed. There are numerous reasons for a slow ceiling fan, but they can be summarized into four main aspects.

Regulator malfunctioned

If it's a new purchase, it might be a faulty ceiling fan speed controller.

2. Lack of lubrication in bearings

If the fan bearing is low on oil, add some (use grease). If there's a short between the windings, the motor will overheat, and it needs to be rewound. To determine if the bearing is faulty, listen for sounds; if there's an issue, call a professional repairman.

Capacity of capacitors decreases

Most household appliances are powered by single-phase power, but those with motors require two-phase or higher power supply. What's the solution? Designers have already thought of it. By paralleling a large capacitor in the single-phase circuit, as large capacitors have a lagging effect on AC power (the current in a capacitive circuit lags by 90 degrees compared to a non-capacitive circuit), this effectively converts the single-phase input into a two-phase, allowing the motor to operate normally. The principle we use for our household appliances (single-phase) is the same.

Capacitance value reduced, lack of lubrication leading to increased friction, or inter-turn short circuits in the motor can cause the capacitance value to decrease. While it is appropriate to increase the capacitance value, it should not be excessively high, as this can raise the motor temperature and affect its lifespan. This is a synchronous motor, where the speed is determined by the frequency of the power supply. If the motor is not equipped with blades and operates at 100 RPM, adding blades will still result in 100 RPM. However, if more blades are added, the load becomes too heavy, preventing the motor from starting. The spring then repeatedly assists in starting the motor.

Additionally, a slow rotation doesn't necessarily indicate issues with the capacitor and bearings. The capacitor ensures the fan rotates in the pre-set direction. Check if the blades are deformed, reducing the windward surface area, which can affect the air volume. Also, inspect if the speed controller has poor contact, causing the gear to be in a low-speed position.