In this work, a Neuro-Wavelet Network (NWN) based method is proposed to calculate the critical triggering angle of DC motor fed by the three phase controlled rectifier. Firstly, the critical triggering angles for DC motor drive system are computed at different operation conditions. Afterwards, the NWN is trained with this data. The critical triggering angle is derived from NWN for any operation condition. The several simulation examples have been given to illustrate the performance and effectiveness of the proposed method. The simulation results of the drive system show that the critical firing angle is determined precisely with the NWN.