| 摘要 |
PURPOSE:To enhance the workability even if slight capacity is sacrificed. by providing a thermistor in a heat sink unit of an output transistor and inputting the temperature of a heat sink unit to a controller. CONSTITUTION:When a comparator 13 judges that the signal from a heat-sensitive element 15 becomes the first set value 14a due to the temperature rise of a heat sink unit 4 during the operation of an inverter, the inverter is not immediately stopped, but the operating frequency F is decreased to continue the operation. Further, when the temperature of the unit 4 rises to increase to the value corresponding to the second set value 14b, an output drive signal 12 is controlled to become the minimum frequency in order to protect the output transistor 3 in the inverter device against the thermal damage. |
