What's the difference between disc, single cylinder and double cylinder permanent magnet governors?

The disc permanent magnet governor was patented in the United States, and the barrel structure was produced in China. Because of the influence of patent, it is necessary to add a barrel to the disk structure, so it is called barrel structure. Compared with the simple, safe and reliable disk structure. It is difficult to install the cylinder structure, which needs leveling and alignment, and heat dissipation is also a difficult problem. An increase in temperature means a decrease in life. Vibration is also a difficult problem for permanent magnets. The cylinder is the link between the load and the motor, which links the motor and the load into a frequency vibration in phase. There are only two disc structures in China: Magna and Anhui Wolf. These two companies are also recognized as leading enterprises of permanent magnet governors. Magna's cooling method is water cooling, and Wover's cooling method is oil cooling. Oil cooling is to take away heat by circulating turbine oil on the permanent disk, and water cooling is to use machine seal for cooling. The permanent magnet governor invented in Europe and America itself is a disk structure, and when it is introduced to the mainland, it becomes a single cylinder, a double cylinder, a shielding cylinder and various structures. No right to use disk structure.