| 摘要 |
PURPOSE:To approach the power of a cooling auxiliary machine to an ideal power of the prescribed machine by starting a motor of the auxiliary machine through a frequency setter at its starting time, and controlling the operation in response to a load rate of a transformer after the prescribed time. CONSTITUTION:The load of a transformer 1 is detected through a CT3 by a load rate detector 4, and the detector produces a control signal to a variable frequency converter 5. The detector 4 controls the frequency of a cooling auxiliary machine power source along a curve C in response to the load of the transformer. A curve G (load rate I1, auxiliary machine power P1) is the power of the auxiliary machine of the operable limit of the case that the motor is controlled to gradually decelerate from high speed rotating state in a range lower than the point D on the load rate I2, i.e., characteristic curve. An auxiliary relay and a time limit relay are excited by a cooler operation signal. Accordingly, when the cooler 2 is started, the signal of the detector 4 is opened by the contact 7b of the auxiliary relay, and the signal of the frequency setter 6 set to be able to start the motor is input to the converter 5. |
