| 摘要 |
PROBLEM TO BE SOLVED: To reliably control a cooling means by cooling a coil with a cooling instruction value that is outputted by an operation using an induction back electromotive voltage of the coil, a voltage value across the coil, and a coil current value being obtained based on a traveling speed and a thrust constant of a motor. SOLUTION: A current instruction signal is outputted from a D/A converter 15 to a current amplifier 2, and a drive current exactly according to an instruction value is applied to motor coils 1a-1c being provided at an XY stage 11. A drive current from the current amplifier 2 is prohibited by an output prohibition switch 4, and either coil is selected by a selection switch 3 of the motor coils. A differential amplifier 6 detects a voltage that is generated by a current flowing to a current detection resistor 5 via the motor coils 1a-1c as a current measurement voltage and converts it to digital data by an A/D converter 7. A current instruction value that is set by a CPU 16 is converted by the D/A converter 15, is outputted to the current amplifier 2 via the output prohibition switch 4, is converted to a cooling instruction value by a D/A converter 19, and is outputted to a cooling device 20. |
