| 摘要 |
PURPOSE:To suppress electromagnetic wave noise by providing a function to change conduction control of a DC motor from usual chopper control to continuous conduction control in specific conditions. CONSTITUTION:A DC motor 6 is controlled by continuous conduction control in specific conditions determined by the temperatures of the field effect transistors (FET's) 41-44 of a chopper circuit 5 and other factors. Therefore, a temperature sensor 12 is installed to monitor the temperatures of the FETs 41-44 of the chopper circuit 5. Temperature data are stored as a signal AD3 into a microcomputer 9 and, as a result of it, continuous conduction control is performed instead of chopper control only when the temperatures are lower than specified. Thereby electromagnetic noise caused by chopper control can be suppressed. |
