Induction machines (IM) with multiple sets of three-phase windings are a real alternative in safety critical applications due to their inherent redundancy and extra number of freedom degrees. These properties can be used to develop a fault-tolerant system without extra hardware. The fault detection is mandatory in the creation of a fault tolerant system. Since, the fault localization allows to adapt the control scheme of this anomalous mode of operation. Nowadays, open-phase faults (OPFs) and six-phase IMs are hot topics in the literature of fault-tolerant drives. Thus, this paper presents an open-phase fault detection method for a six-phase IM drive. The detection method is based on the vector space decomposition (VSD), taking the components of the secondary orthogonal subspace to localize the open-phase fault. The goodness of the proposed method is validated with simulation results.