| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent trouble from occurring to electric equipment due to heat by suppressing a rise in the temperature in a control box and to enable low-cost constitution. SOLUTION: A cooling fan 1 is equipped with a partition plate 2 made of a nonmagnetic insulator, a motor-driven fan 3 fitted to one surface of the partition plate, and a driven fan 4 fitted to the other surface of the partition plate. The motor-driven fan has a drive-side rotary body 8 having a permanent magnet 9 arranged closely to the partition plate. The driven fan is equipped with a driven-side rotary body 13 having a nonmagnetic conductor 16 which is arranged nearby the partition plate opposite to the permanent magnet, and a magnetic plate 14 which is arranged and fixed opposite to the permanent magnet across the nonmagnetic conductor. An eddy current is generated at the nonmagnetic conductor by electromagnetic induction based upon the movement of the permanent magnet when the motor-driven fan rotates, and this eddy current receives a Lorentz force, so that the driven fan rotates following up the motor driven fan.</p> |
