| 摘要 |
PURPOSE:To enable to operate compressors in a stable manner, by employing such an arrangement that compressors controlled by a control unit having a function to control the number of operative compressors can be also operated under the control of other control units capable of controlling the number of operative compressors. CONSTITUTION:In case that control on the number of operative compressors is not effected by a control unit 3A, for instance, by reason that the control unit 3A is inoperable or its power source is cut off, the control unit 3A gives an ''inoperable'' signal D to a switching means 7. Here, since the gate of a transistor 8 is energized in the above state, the switching means 7 gives ''individual operation'' signals K2-K4 to other control units 3B-3D automatically irrespective of the position of a selector switch 9A. Resultantly, operation of the control units 3B-3D is switched from the mode of controlling the number of operative comparessors to the mode of individual operation, and operation of compressors is continued. |
