DC Motor Analysis

 

Simple Steady State Performance Analysis

Inputs:   Motor RPM Constant (Kv), Motor Torque Constant (Kt), Motor Stator/Coil Resistance,

                Motor Zero, Load Current, Required Torque, Applied Voltage

Outputs:  Amps Drawn, Power Used, Power Produced, Efficiency, Heatload, Current

Analytical Work

              Theory/governing Equations

Motor constants:  –Io = 3A, –R = 0.111W, –Kv = 256 RPM/V

                  Linking to propeller model

Converge on RPM using Fixed Point Iteration (FPI)
  • Difficulties
    • Motor constants are NOT CONSTANT!
    • Without experimentally measured torque they cannot be calculated

 

Propeller module in isolation

 

Motor module in isolation

•Torque calculated based on power used rather than power produced, this explains the approximate 3A shift between the actual and predicted

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                  Motor Module Results Comparison

  • Deviation at high voltages due to non-constant motor 'constants'