| 摘要 |
PURPOSE:To suppress the noise of a cooling fan by installing a control means which controls the revolution speed of a cooling fan according to the inside temperature of a control panel. CONSTITUTION:Temperature sensors 1A and 1B for detecting the inside temperature of a control panel are installed. The revolution speed of a cooling fan 4 is increased and decreased according to each detected temperature of the temperature sensors 1A and 1B by a control means 3, and during time when the temperature in the control panel is low, at least noise is suppressed. Further, when the temperature in the control panel is low, temperature rise is suppressed by driving the cooling fan 4 by the driving device 3, and the operation time generating large noise can be shortened, and noise can be suppressed as a whole. |
