通常出现问题是过载或欠载引起的，但是在允许值之间的相对范围是比较宽的。

When problems occur, they are usually due to clear overloading or underloading; but a relatively wide range of operation is possible between these extremes.

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欠平衡钻井技术可以降低地层损害、提高机械钻速，所以在世界范围内被逐渐采用。

Underbalanced drilling technology can increase ROP and decrease formation damage, so it is increasingly used worldwide.

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正常源每一相位的欠压传感：起始电压可在额定值85 - 100%的范围内调节；回动电压可在始动值75 - 98%的范围内调节。

Undervoltage Sensing for Each Phase of Normal Source: pickup voltage is adjustable form 85 to 100 percent of nominal, and dropout voltage is adjustable from 75 to 98 percent of pickup value.

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