| 摘要 |
PURPOSE:To reduce input to a cooler's auxiliary machine and to permit energy saving by a controller wherein the load current flowing through a winding of a transformer is detected, the detected current is converted to a small control input signal, and this signal is input to a variable frequency inverter to vary the frequency, so that the power required for the auxiliary machine is consumed in accordance with the load. CONSTITUTION:At the same time when a transformer 1 starts its operation, a switch 18 is closed and an oil feeding pump 5 is driven, so that an insulating oil circulates in the flow course of a tank 2 connecting pipe 4 tank 2. On the other hand, a load current flowing through the transformer 1 is detected by a current transformer 14. The secondary current of the current transformer 14 is input to a converter 15. A control input signal from the converter 15 is input to a variable frequency inverter 16. The variable frequency inverter varies the control input signal to a certain frequency, whereupon all motors 7 start to rotate and fans 6 are also rotated simultaneously, thus blowing the cooling wind produced at the time to the connecting pipes 4. Insulating oil is cooled while passing through each connecting pipe 4, and the cooled insulating oil is returned back to the tank once again. |
