CONTROLLER FOR ROTARY MACHINE GROUP OPERATION

PURPOSE:To automatically and securely prevent bearing damage due to a shortage of an oil film by controlling respective rotary machines individually so that a specific rotary machine is in a stop state continuously for a certain time and a necessary irreducible number of rotary machines are in operation. CONSTITUTION:An operation history measurement part 11 measures the past operation time tD, stop time tS, etc., of respective cooling machines 61-6n individually according to the actuation signals of the respective cooling machines which are operated, correctly stores them as an operation history signal P, and outputs it to a sequence control part 12 at need. The sequence control part 12 calculates the necessary irreducible number of cooling machines to be operated, determines cooling machines to be operated actually in the cooling machine group 6 according to the operation history signal P, and outputs control signals C1-Cn to a command part group 131. At this time, the cooling machine which has the longest stop time tS is given the top priority of operation actuation and the cooling machine which has the longest operation time to is given the bottom priority of stopping. Consequently, the early damage of the bearing due to the shortage of the oil film is automatically and securely prevented.