What Is Motor Stall Protection?
Motor stall protection plays a crucial component in motors. To help you know the stall protection in motor clearly, this article will introduce motor stall protection from motor stall definition, motor stall reason, motor stall protection methods, and so on.
What is motor stall?
Motor stall refers to the phenomenon that the motor’s rotor cannot rotate normally due to excessive external load or insufficient power supply during the starting or running process of the motor. In the locked-rotor state, although the motor continues to consume electrical energy, the rotor does not rotate, causing excessive current and heat to be generated inside the motor. If this state continues for too long, it may cause damage to the motor or other safety issues.
What causes motor stall？
Motor stall is a common problem, which may cause equipment damage and production interruption, affecting production efficiency and safety. Understanding and identifying the causes of motor stall is key to preventing and quickly resolving problems. Here are some common causes of motor stalling:
- Excessive load
When the load on the motor exceeds its designed carrying capacity, stalling may occur. This usually occurs when mechanical equipment becomes stuck or overloaded, preventing the motor from producing enough torque to overcome the external load.
- Power supply problem
If the power supply voltage is too low or fluctuates too much, it will directly affect the operating performance of the motor. If the voltage is unstable or too low, the motor may not start or generate enough torque during operation, resulting in stalling.
Wrong phase sequence (three-phase motor) can also cause the motor to not operate properly or stall.
- Mechanical failure
Damage to the mechanical parts inside the motor, such as worn or damaged bearings, may cause friction or jamming between the rotor and stator, causing stalling.
Failure of the gearbox or transmission mechanism may also cause abnormal load on the motor, leading to stalling.
- Control system failure
Improper setting of the motor’s starter or frequency converter, or failure of the control system, may not correctly control the starting and running of the motor, causing stalling.
Improper setting of control parameters, such as setting the acceleration time too short, may also cause the motor to stall during the starting process.
- Environmental factors
In some specific environments, such as high temperature or excessive humidity, the performance of the motor may be affected, leading to stalling.
Environmental pollution such as dust and oil may also limit the function of the internal components of the motor and cause stalling.
- Improper maintenance
Irregular maintenance and inspection may lead to some early problems of the motor not being discovered and solved in time, such as increased friction caused by insufficient lubrication, which may eventually cause the motor to stall.
What is motor stall protection?
Motor stall protection is a safety and protection used in various motor-driven applications to prevent damage when a motor is motor stalling. It is also known as Motor Jam Protection. Our motor protection relays can provide motor stall protection.
How does our motor protection relay work for Motor Stall Protection?
Motor stall protection mechanisms typically monitor the motor’s current, speed, or both. Here’s how they generally function:
Current Monitoring: Since a stalled motor draws a much higher current than under normal operation, monitoring systems can detect an unusual increase in current flow. When the current exceeds a predetermined threshold for a specific duration, the system triggers a protective action.
Speed Monitoring: Some systems monitor the motor’s rotational speed. A significant drop in speed or zero speed (when the motor shaft is expected to be moving) can signal a stall condition.
However, our motor protection relays are mainly based on current monitoring. During the starting process, it is judged whether to activate the protection based on the ratio of the maximum line current measurement value and the motor-rated current value. This function is enabled during the starting process and will be automatically locked after the starting is completed.
Locked rotor protection parameter setting range:
Protection action mode | shutdown/alarm/trip |
Action value | 100 ~ 1000% Ie |
Action time limit | 0.5 ~ 50.0 s |
Motor stall protection is critical in numerous applications across various industries, including:
Pumps: To prevent damage due to dry running or blocked impellers.
Conveyor Systems: To detect and address blockages or overloads that prevent the belt from moving.
Fans and Blowers: To prevent damage when airflow is obstructed or in situations where the fan blade is hindered.
Automated Machinery: In automated production lines, stall protection can prevent machinery damage and ensure operational safety.
Implementing effective stall protection in motor not only ensures the longevity and efficient operation of motors but also enhances the overall safety and reliability of mechanical and electrical systems in industrial settings.
