| 摘要 |
PURPOSE:To make a filter function as a common mode noise measure work effectively during heating operation and reduce leakage of electric currents from a power line of a cooler outdoor unit during cooling operation. CONSTITUTION:Ends of common mode capacitors C1 and C2 are respectively connected to phases R and S of a power line of an indoor unit 1, and a series capacitor C is provided between the other ends of the capacitors C1 and C2 and a ground G. In addition, a keying circuit B with a switch contact Ry1-b that is opened during cooling operation and shorted during heating operation is connected in parallel to the series capacitor C. During cooling operation, the series capacitor C is connected in series with the common mode capacitors C1 and C2 to increase the impedance to the earth and reduce leakage of electric currents. During heating operation, the series capacitor is omitted to reduce the impedance to the earth and effectively attenuate common mode noise.
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