This paper describes multi-slice modelling and validation of an axially skewed synchronous machine in 2D domain. The technique involves coupling of circuit and electromagnetic domains together with carefully constructed geometry. The model size in comparison with full 3D simulation reduces considerably. Developed 2.5D multi-slice model allows fast simulation in 2D domain, still taking into account 3D effect of skew on torque and back-EMF of the machine. Simulation results in 2.5D and 3D domains are compared to measurements. All simulations are performed using free and open-source tools.