Design and Performance of a Water-cooled Permanent Magnet Retarder for Heavy Vehicles

This paper proposes a novel permanent magnet retarder (PMR) structure that uses water cooling to improve the braking performance of conventional PMR for heavy vehicles. A finite element model for a water-cooled PMR was developed by considering the temperature dependence of magnetic characteristics and heat conductivity. The eddy current and temperature distribution were analyzed using the magneto-thermal coupled method. Retarder performance was tested at a test bench. The test results show that the calculated temperature and braking torque agreed fairly well with the measured results. PMRs can maintain a low working temperature by using water cooling. Compared with air-cooled retarder, this retarder´s braking torque does not decrease much under continuous working conditions.