How to judge motor performance by no-load current

Voltage and current are standards that reflect the performance of micromotors. For example, there are complex internal relationships between rated voltage, current, and no-load current data. When the value exceeds the nominal value, it should be judged whether the micromotor will fail. So how to judge the performance of the micromotor according to the no-load current?

For micromotors, a slight no-load current can improve the power factor of the micromotor. When the no-load current of the micromotor is large, since the winding area of the rotor of the micromotor is constant, the current through the conductor is also constant, so the actual current can only be reduced, and the load that the micromotor can drive will also decrease. The power of the micro-motor is reduced, the load is too heavy, the winding is easy to heat up, the life of the micro-motor is shortened, and the motor is burned out. If the no-load current is too small, the starting torque and maximum torque may not meet the requirements.

The ratio of micromotor quiescent current to rated current

The no-load current of the micro motor is 30%~70% of the rated current, while the no-load current of the large and medium motors is 20%~40% of the rated current. The load current refers to the stator current value detected when the micromotor drives the load. This value will vary with the size of the load.

Generally speaking, when the torque of the output shaft of the micromotor is zero, it is considered to be idling, and the current in the windings of the micromotor is mainly the excitation current, which is called no-load current. The excitation current is the main component of the no-load current used to generate rotation. The rotating magnetic field is the reactive component of no-load current, but a small part is no-load iron loss, non-mechanical load loss, leakage loss, etc. Reactive components can be ignored in profiling. Therefore, no-load current can be regarded as reactive current.