This paper investigates the stresses, losses and the lifetime of the dc-link inductor and capacitors of 12-Pulse Variable Frequency Drives (VFD) due to Type A, Type B Sags and voltage unbalances. These parameters are mainly attributable to the rectifier’s transition into unbalance and single-phase operation, giving rise to low-order harmonic voltages (100Hz, 200Hz etc.,) at the DC Link. When one type of Sag is imposed in the primary of the 12 Pulse transformer, it will transform into another Sag type in its secondary windings based on the transformer configuration. The transformed Sag will be different between the secondary windings. So, the rectifiers will experience a different current profile, which will increase the low-order harmonics in dc-Link of the VFD. This variation in the low frequency components will affect the lifetime of dc-bus Capacitors. This will increase the ac-flux densities of the DC Choke which will lead to increased core loss and saturation. The analysis predicts the life of the DC capacitors and core loss of the DC-Link inductors under different types of Sags and unbalances. 12-Pulse VFDs are generally used for high-Power. But for the analysis, simulation and testing, a 12-Pulse 7.5kW VFD is used.