| 摘要 |
PURPOSE:To drive the remaining non-trouble accessories at the number of revolution corresponding to a load current, and to contrive to economize in electric power by a method wherein the number of revolution of the accessories is computed from the detected number of nontrouble accessories and the load current, and an inverter is controlled to obtain said number of revolution. CONSTITUTION:When a part of accessories 3 and 4 are in trouble, a control part 6 detects the trouble by close-circuiting an auxiliary contact point 11c, and an inverter 7 is controlled in such a manner that the number of revolutions of the accessories is set at the value in coincidence with the curved line D indicating the number of accessories in operation. When all the accessories are normal and they are driven at the number of revolutions of the point P on the curved line C indicating the number of accessories in normal operation and also when a part of the accessories is in trouble, its operation is suspended, and the number of accessories in operation is reduced, the load factor on the curved line D moves to the point Q, and the number of revolutions of the accessories is increased. When the load factor of the transformer is changed, the number of revolutions of the accessories changes to the number of revolutions at a point on the curved line D corresponding to the load factor appropriate to the above-mentioned change. As a result, when a part of the accessories is in trouble, the number of revolutions of the non-trouble accessories is increased so that the number of revolutions of the accessories in trouble will be compensated, and the required cooling functioning can be obtained.
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