Stalling refers to the situation where the motor rotor cannot rotate due to excessive load or other reasons during the operation of the motor. For the DC motor of the grinder, stalling has the following hazards:
1. Damage to the motor itself
Overheating damage:
When the motor is stalled, the current will increase sharply. This is because when the motor is running normally, the current is mainly used to generate a rotating magnetic field and overcome a certain load resistance. When the motor is stalled, the rotor cannot rotate, the relative movement between the rotating magnetic field and the rotor becomes extremely small, and the back electromotive force of the motor is almost zero. According to Ohm's law, the current at this time is only limited by the resistance of the motor winding and will far exceed the rated current.
Excessive current will cause the motor winding to heat up rapidly. If the stall time is long and the heat continues to accumulate, the temperature of the motor winding will rise sharply, which may exceed the heat resistance limit of its insulation material, causing insulation damage, and even causing the winding to short-circuit and burn.
Mechanical damage:
When stalled, the output torque of the motor cannot overcome the load resistance, which will cause a lot of mechanical stress inside the motor. This stress may cause the motor's shaft, bearings, gears and other mechanical parts to deform and damage.
For example, the shaft may bend due to excessive torque, and the bearing may wear out or even be damaged due to excessive friction.
2. Impact on power supply and control system
Power supply overload:
The high current when the motor is stalled will put a great burden on the power supply. If the power supply capacity is insufficient, it may cause the power supply voltage to drop, affecting the normal operation of other equipment.
In severe cases, the power supply overload protection device may be activated, such as fuse melting, circuit breaker tripping, etc., interrupting the power supply of the entire circuit.
Control system failure:
For grinders with control systems, motor stalling may affect the normal operation of the control system. For example, the controller may trigger a protection mechanism, stop the motor operation, or send an error signal due to detecting excessive current.
Long-term stalling may damage the electronic components of the controller and affect the stability and reliability of the control system.
In summary, the DC motor of the grinder cannot be stalled. During use, excessive load or other reasons should be avoided to prevent the motor from stalling to ensure the normal operation and service life of the motor.