定期交换 meaning in English

exchange periodically

The regular exchange of information on disease vectors surveillance in port areas was launched in january 2005
此外，有关港口地区病媒监察的定期交换资讯工作，已在二零零五年一月展开。
Balance of three phase can be restored by exchanging the positions of the conductors at regular intervals along the line so that each conductor occupies the original position of every other conductor over an equal distance
平衡三相可以被定期交换指挥的位置恢复沿着线，以便每个指挥占领其他指挥的原始位置在一个相等的距离。