| 摘要 |
PURPOSE:To protect an air-conditioner upon occurrence of nonconduction of three-phase output from an inverter unit for feeding power to a three-phase induction motor having three-phase winding of two systems or more. CONSTITUTION:In an inverter controller 9c for air-conditioner provided with two or more systems of inverter units for feeding power to a three-phase induction motor 15 having three-phase winding of two or more systems, three- phase output currents from the inverters 9a, 9b are detected, respectively, through current detecting means 16a, 16b. A nonconduction decision circuit 17 connected with the current detecting means 16a, 16b makes a decision of nonconduction of three-phase outputs. When a decision is made that one or more systems are nonconducting an abnormality signal is delivered to a protection control circuit 18 connected with the nonconduction decision circuit 17 and the protection control circuit 18 protects an air-conditioner. |
