motorparameters

Motor parameters are numerical specifications and characteristics that describe how an electric motor behaves under electrical excitation and mechanical load. They are used in motor selection, control design, and dynamic modelling, and are typically reported by manufacturers in datasheets.

Electrical parameters include rated voltage, rated current, stall current, resistance, inductance, back-EMF constant and torque constant, and electrical time constants. These define the electrical input requirements, torque capability, and current limits of the motor.

Mechanical and dynamic parameters include no-load speed, stall torque, continuous or peak torque, rated power, and rotor inertia. The torque-speed curve, efficiency, and power output describe how torque varies with speed and load.

Motor models commonly represent a motor with equations linking electrical and mechanical domains. For a DC motor, V = L di/dt + R i + e, with e = K_e ω and τ = K_t i, and the mechanical equation J dω/dt + B ω = τ - τ_load. Parameters such as J, B, K_t, K_e, R, and L characterize the model.

Thermal parameters describe heat generation and dissipation, including thermal resistance, ambient temperature, temperature rise, and insulation class. These affect continuous operation and maximum allowable currents.

Different motor types have characteristic parameter sets. Brushless DC motors (BLDC) report phase resistance and inductance, back-EMF constants per phase, and pole counts; induction motors report stator/rotor resistances, leakage inductances, and slip; stepper motors report step angle, holding torque, and torque ripple.

In practice, motor parameters are obtained from datasheets or determined experimentally via tests such as no-load speed and stall current measurements, system identification, or dynamic testing. They enable accurate drive design and control tuning.