| 摘要 |
PURPOSE:To permit effective power factor improvement by adopting a feedforward system, in which the number and rpm of working motors are previously detected and an on-off signal determining the capacitance and number of phase advancement capacitors is given on the basis of sheduling. CONSTITUTION:An rpm alarm setter 5 gives setting conditions to a scheduling unit 6 on the basis of the output of an rpm detector 4 detectng the rpm of an induction motor. The unit 6 determines the optimum phase advancement capacitor 7 on the basis of a scheduling table previously worked out on the basis of the number and rpm of induction motors controlled by Scherbius control, and it gives a command for connecting and disconnecting phase advancement capacitors 7 with respect to a relay circuit 11. With this command breakers 8 to 10 are operated to effect connection of required capacitors 7. In this way, the power factor of the system is set under the optimum condition, and effective improvement of power factor can be obtained. |
