| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection circuit that prevents the wrap-around of a lightning surge from a machine tool to a numerical control device, in a device in which power supplies of the numerical control device and the machine tool are arranged, respectively. SOLUTION: This lightning surge protection circuit is characterized in that: power supply passages of the machine tool 40 that uses a motor and the numerical control device 30 that controls the machine tool are constituted at a power source, respectively; the numerical control device 30 is for use in the machine tool or the like in which control signals of the machine tool 40 and the numerical control device 30 are connected by a signal line; the control device comprises a first converter 11 that converts an electrical signal to an optical signal and a second converter 15 that converts an optical signal to an electrical signal; the power supply passages of the control device are connected via a first lightning-proof transformer 5; the power supply passages of the first converter 11 are connected via the first lightning-proof transformer 5; and the power supply passages of the second converter 15 are connected to the power supply passages that pass through a second lightning-proof transformer 22 via the first lightning-proof transformer 5. COPYRIGHT: (C)2006,JPO&NCIPI
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