Recently, brushless dc generator (BLDCG) becomes a very attractive alternative to its counterparts in many applications such as wind energy systems and transportation systems. That is because of its advantages which are high efficiency and energy density, light weight, compact design and low maintenance. The main problem has appeared in BLDCG applications which are characterized by large speed fluctuations like wind turbines and internal consumption engines. This speed variation leads to changes in the BLDCG output voltage. The goal of this study is keeping the generator output voltage constant with the speed variation of the prime mover using a simple control means includes a variable reactor. This work in BLDCG is presented for vehicle application, to be instead of the brush claw pole synchronous generator. Throughout the present work, a mathematical model of BLDCG is developed and used in computing the generator characteristics. An experimental setup is implemented for verifying the theoretical analysis. A comparison between the theoretical and experimental results confirms the validity of proposed analysis. The results show the good performance of BLDCG with the proposed simple control method.