| 摘要 |
PROBLEM TO BE SOLVED: To prevent coil overheat by storage of joule heat since current value continues in relatively small condition in a linear motor. SOLUTION: In a protection equipment for a linear motor with composition in which a permanent magnet and a coil relatively motion, (a) a detection means for current applied to the coil, (b) a multiplication means which calculates square value of the detected current at regular time intervals Δt, (c) a storage means which sequentially stores square values from first one to nth one after inputting the square value, deletes the first square value when nth square value and the first square value are input and repeats same operations afterwards, (d) an additional means which calculates a summation of n's square values in the memory means, (e) a setting means for standard value which compares to the summation of the square values, (f) a comparison means which outputs over load signal when the summation of the square values are compared to the standard value and the summation then rises above the standard and (g) an over load prevention means which protects the coil by controlling a driving equipment of the coil in receiving the over load signal are provided in the invention. |
