Abstract – This paper presents electromagnetic analysis of two permanent magnet transverse flux outer rotor machines with and without magnetic shunts. The research started with designing and analysing a permanent magnet transverse flux machine with inner rotor, previously patented by J. Giearas in 2010. However, the results obtained from the prototype test differed significantly from the estimated results. Applying 3D Finite Element Method tool main problem of the machine was detected. The problem was in high flux leakage which weakened magnetic flux density in the stator poles. Such observation led to designing two machines with outer rotor; with and without magnetic shunts. The role of the magnetic shunts is to minimize flux leakage in the stator in order to improve performance of the machine. Electromechanical parameters of both outer rotor machines, with and without magnetic shunts, are compared in the paper. 3D Finite Element Method results are supported by laboratory analysis of the machines’ prototypes. Experimental measurements proved that the machine with magnetic shunts demonstrated better performance comparing to the machine without magnetic shunts. Presence of the magnetic shunts in the machine resulted in reducing of flux leakage and cogging torque. Index Terms – Transverse-flux generator, magnetic shunts, flux leakage. I. INTRODUCTION ermanent Magnet Transverse Flux (PMTF) machines are popular due to their simple configuration and high power density. They are also more compact than other types of PM machines. There are many topologies of PMTF machines which were patented in the past [1-5]. Various articles in the literature have intended to improve the design of existing topologies of PMTF machines [5-10]. Such interest is caused by the fact that PMTF machines still are not studied well. In [11] G. Gieras, scientist and author or the most recent topology patented on PMTF machines, notes: “... the technology of transverse flux machines is still not mature.” Main challenges which may arise during the design of PMTF machine - high leakage flux and high cogging torque. Leakage flux in PMTF machines usually depends on the topology configuration. In this paper, the topology patented by J. Gieras with inner rotor was modified, and two machines with outer rotor with and without magnetic shunts were built. Magnetic shunts are laminated steel sheets glued together and placed between stator poles. The main role of the shunts is to block magnetic field of PMs situated between the poles at particular time instant [12]. High cogging torque of PMTF machines is caused by the interaction between magnetic field of PMs and stator poles [12]. Since the number of stator poles in PMTF machines is two times lower than the number of rotor poles, cogging effect is significant and has to be taken into account. This study is intended to find an optimal design of PMTF machine by comparing two machines with different configurations: machines with and without magnetic shunts. II. TOPOLOGY OF PMTF MACHINE ACCORDING TO J. GIERAS As it was mentioned, PMTF machines differ by their topologies, but principle of operation is the same. Topology patented by J. Gieras in 2010 is studied. 3-phase PMTF machine proposed by Gieras is shown in Fig. 1. Fig. 1. J. Gieras topology of PMTF machine: 1, 11 – housing, 2, 6, 9 – yoke segments, 3 – coil, 4, 7, 10 – stator segment, 5, 8, 12 – stator assembly, 13, 14, 15 – stator segment, 16, 17, 18, 19, 20, 21 – permanent magnets, 22 – shaft, 23, 24, 25, 26, 27, 28 – rotor assemblies [5]. The machine consists of the housing, and three identical rings. Each ring is composed of stator (stator segment, yoke segment, and stator assembly), permanent magnets, coil, and rotor assembly. One-phase ring of the machine is shown in Fig. 2. Comparison Analysis of PM Transverse Flux Outer Rotor Machines with and without Magnetic Shunts Oleksandr Dobzhanskyi, Rupert Gouws and Ebrahim Amiri P