Brushless motors (BLDC motors) are widely used in various devices, such as power tools, fans, robots, etc. The brushless motor controller is one of the core components for the normal operation of the motor. It is responsible for the motor’s start-up, speed regulation, and reverse control. If the controller fails, the motor will not work properly. X-TEAM will introduce the common fault phenomena of brushless motor controllers and provide some repair methods to help you solve the problem.
- Common fault phenomena
1) The motor cannot start
This is one of the most common faults, usually manifested as no response after the brushless motor is powered on. Possible reasons include:
The internal circuit of the controller is damaged, resulting in the inability to output signals.
The power input voltage is insufficient or unstable.
The Hall sensor of the motor fails and cannot provide the correct position signal to the controller.
2) Unstable motor operation
The motor may experience speed fluctuations, difficulty starting, or unstable rotation. Common reasons are:
There is a problem with the speed regulation circuit inside the controller, resulting in unstable output current.
The driver chip of the controller fails, affecting the precise regulation of current.
3) Motor overheating
Motor overheating is another common problem, which usually manifests as controller overheating or motor overheating after long-term operation. The reasons may be:
The controller load is too large and the drive current is too high.
Poor heat dissipation causes abnormal temperature rise of the controller or motor.
- Repair steps of brushless motor controller
1) Check the power input
First, make sure the power supply is normal. Use a multimeter to check whether the input voltage is within the rated range of the motor controller. If the voltage is insufficient or unstable, you may need to replace the battery or adjust the power system.
2) Check the controller circuit
If the power supply is normal, then check the internal circuit of the controller. Common problems include:
(1) Damaged capacitor: The capacitor is an important filtering component inside the controller. If the capacitor is damaged, it may cause the motor to fail to start. Check and replace the damaged capacitor.
(2) Broken or cold solder joints on the controller motherboard: The solder joints on the motherboard may become cold due to long-term use. Check and re-solder the problematic solder joints.
3) Check the Hall sensor
Brushless motor controllers usually require Hall sensors to provide feedback signals. If the Hall sensor is damaged or the signal is inaccurate, the motor will fail to start or run unstably. Use an oscilloscope to check whether the output signal of the Hall sensor is normal. If a fault is found, the sensor needs to be replaced.
4) Check for overheating problems
If the motor or controller is overheating, first check the cooling system of the controller. Make sure that the heat sink or fan is not blocked and the ventilation is good. If the controller temperature is too high, the problem can be solved by reducing the load or adding additional cooling devices. In addition, check the current output of the controller to avoid overload operation.
5) Replace damaged parts
If after the above inspection, it is determined that some parts of the controller such as the power module, driver chip, filter capacitor, etc. are damaged, it is recommended to replace these parts. For ordinary users, the most direct approach is to replace the entire controller instead of repairing them one by one.
- Prevent controller failure
Failures of brushless motor controllers are usually caused by long-term use, overload, and harsh environmental conditions. In order to extend the service life of the controller, it is recommended to maintain the controller regularly, ensure stable power supply, avoid overload use, and regularly clean the cooling system of the controller.
Failures of brushless motor controllers are not unrepairable. Most problems can be effectively solved through reasonable fault diagnosis and processing. Whether it is power supply inspection, internal circuit inspection, or replacement of damaged parts, professional knowledge and meticulous operation are required. For users who have no maintenance experience, it is recommended to contact professional maintenance personnel for repair to avoid greater damage due to improper operation.
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