Fan often we encounter anywhere, one of them in the industry. Fan in the industry typically used to cool the machine is operating. If the fan is used on an ongoing basis then it can cause damage to the components. One of the components that often are damaged i.e. bearing. One way to monitor a condition of bearing vibration-based method. Envelope is one method of vibration-based. Envelope method capable of extracting impact impact with low frequency even hidden by other vibrational signals. This research aims to know the trajectory of the ball bearing outer defect and path in the use of the frequency spectrum and the spectrum envelope. This research was conducted by recording vibration signal on ball bearings normal conditions, disabilities, and disability in the trajectory path of the outside using an accelerometer is done separately. The data obtained are then processed on matlab software and plotted on a time-domain and then transformed to the frequency spectrum and the spectral envelope using FFT (Fast Fourier Transform). The results of the data processing are then identified defects in bearings using formulas Ball Pas Frequency Outer Race (BPFO) and Ball Pas Frequency Inner Race (BPFI) to find out the frequency of defects in bearings. The results showed a high amplitude vibration spectrum at frequencies beyond the path of disability (BPFO) followed by 4 harmonic. While the spectrum of vibrations at the frequency of defects in the pathway (BPFI) shows high amplitudes with 5 harmonic. Where is the flaw in the trajectory it produces pads amplitude modulation wave, amplitude modulation wave in the spectrum is characterized by the presence of side band (sb). Advantages of envelope that is able to filter out the complicated signals so that the frequency of component damage can be identified.