This study provides a survey on thermal and flow network analysis of open self-ventilated (OSV) machines. The improvements and new approaches proposed in the last decade are analysed in detail. The thermal analysis of OSV machines is divided into two significant steps, thermal models and flow network analysis. In the first step of this survey, the analytical thermal model approach is considered in detail. In addition, the study provides an overview of the critical parameters of an analytical thermal model and discusses different solutions to overcome the problems. In the second step, the hydraulic behaviour of OSV machines is considered by using the analytical flow network analysis and the formulation to calculate the flow network parameters is provided.