| 摘要 |
PURPOSE:To stabilize output characteristic in a wide range from a high speed to a low speed by switching the connection of the power line of an AC motor. CONSTITUTION:When the speed of a spindle motor 2 exceeds a set speed so that a speed detection signal is switched from OFF to ON, a switching request command from a programmable controller 3 is turned ON, and it is input to a spindle switching circuit 11. Thus, a motor current is interrupted, and a power line switching command from the circuit 11 is switched from a low level to a high level, thereby driving a relay circuit 4. An electromagnetic contact MC1 is turned OFF by the circuit 4, a MC2 is turned ON, the motor 2 is shifted from a low speed winding to a high speed winding, and the motor current is then again supplied. |
