The time-frequency analysis is plotted in color shade (as can be seen in Fig. 5-6). The principle is that the color shades at interested frequencies are applied for motor condition classification. The interested frequencies are concentrated on 25 Hz, 50 Hz, 75 Hz, 150 Hz, 250 Hz and 350 Hz. Based on the observation, It can be seen that the color shade at some frequencies have changed when the stator phase current of different motor conditions has been processed. The color shades of the broken rotor bar motor at 25 Hz and 75 Hz can show different color shades compared to the result from healthy condition. Additionally, the color shades of the stator short circuit motor at 150 Hz can shows different color shades when the number of short circuit turns increase. Because it is difficult to differentiate the color shades by naked-eye from each condition, the color shades are necessary to be transformed into numbers from Eq. 7 and 8. Beside Fig. 5 shows color shade and among numbers which indicate index numbers of each color. The result of color indexes in different conditions and frequencies is shown in Table 4.