| 摘要 |
PURPOSE:To obtain a highly reliable and economical starting method, by detecting end ring current of a basket-type rotor to detect completion of starting of an electric motor and by separating a starting auxiliary winding from a power source. CONSTITUTION:Number of rotations are detected by a magnetic current converter 5, such as a search coil, etc. and by magnetic flux d caused by durrent passing an end ring 11 of a basket type rotor, and the output is added to a gate 4 of a switching element 3 connected to a starting auxiliary winding 2 for ON/OFF control, and then, the auxiliary winding is separated after completion of starting. It is possible, by doing so, to eliminate a mechanically movable section, such as a centrifugal switch, and to accurately operate for a long period of time. |
