Allowable motor disturbance

The allowable motor torque disturbance magnitudes that satisfy an RMS rate stability or speed variation specification for a closed loop control system are described. Allowable motor disturbance magnitudes are given in terms of peak torque disturbance, disturbance cycles per motor revolution, friction, inertia, lead frequency, and open loop crossover frequency. Examples of allowable cogging and ripple torque disturbances are given. It is shown that high cycle per revolution motor disturbances place the most difficult requirements on the allowable disturbance magnitude. The worst case fractional RMS speed variation for a type II loop and for a type III loop is shown.<>