The entire rotating assembly shall be designed with sufficient rigidity and balanced to provide for a maximum shaft deflection at the lower seal of 0 . 002 " under all operating points between plus or minus 40 % of the flow at best efficiency point ( bef ) on the pump ' s performance curve 整个旋转总装都应该具有足够的硬度,在泵性能曲线最好性能的正负40 %的范围内,在所有工作点,最大的轴偏差限制在0 . 002英寸内。