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The Relationship Between Phase Resistance, Phase Inductance and Stepper Motor

What are phase inductance and phase resistance?

Phase resistance refers to the resistance in each phase coil of a stepper motor. Inside the stepper motor, there are two or more phase coils. Each coil has a phase resistance, and its size depends on the material of the coil. , wire diameter and coil length;

Phase inductance is the static electrical parameter of the motor, which refers to the inductance of the internal winding coil of the motor. It is an important parameter that affects the torque-frequency characteristics of the motor. Generally speaking, the attenuation of the motor output torque is inversely proportional to the phase inductance (that is, the larger the phase inductance, the smaller the torque attenuation. The smaller the phase inductance, the greater the torque attenuation);

The impact of phase resistance and phase inductance on stepper motors

Inductance will affect the vibration, speed and heat of the motor. Under the condition of equal resistance and guaranteed torque, the smaller the inductance, the better. In this way, the motor speed can be higher and the vibration will be smaller accordingly.
The size of the resistor mainly affects the heating and efficiency of the motor: larger phase resistance will cause the motor to generate more heat when working, because resistance losses will occur when the current passes through the resistor. This may require better cooling systems to keep motor temperatures within acceptable limits. In addition, larger phase resistance will also cause the efficiency of the motor to decrease.

What factors will affect phase resistance and phase inductance?

Coil material: The material of the coil affects the phase resistance and phase inductance. Different materials have different electrical and magnetic conductivities, which affect the coil's resistance and inductance.
Coil length and cross-sectional area: The length and cross-sectional area of the coil will also affect the phase resistance and phase inductance. Longer coils increase resistance and inductance, while larger cross-sectional areas reduce resistance and inductance.
Number of turns in the coil: The number of turns in the coil represents the number of coils in the coil. More turns generally result in higher inductance values.
Core material and structure: The core material and structure in stepper motors also have an impact on phase resistance and phase inductance. The permeability and shape of the core affect the magnetic field distribution in the coil and thus the inductance.
Motor lead length: The outlet wire of the motor mainly affects the resistance and has little impact on the inductance. The longer the wire, the greater the resistance.

Updated on: 31/10/2023

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