有没有做UL639测试的朋友啊，帮忙翻译一下标准的几句话。
The opening may be used if, within the enclosure, there is no uninsulated live part or enamel-insulated wire less than Xinches (mm) from the perimeter of the opening, as well as within the volume generated by projecting the perimeter X inches (mm)
normal to its plane. X equals five times the diameter of the largest diameter rod that can be inserted through the opening, but not
less than 6-1/16 inches (154 mm).
54 Mechanical Strength Tests for Enclosures
54.1 The external enclosure of a product containing high-voltage circuits shall withstand a 25
pounds-force (111 N) for 1 minute without:
a) Permanent distortion to the extent that spacings are reduced below the values specified in
Spacings, General, Section 21;
b) Transient distortion that results in the enclosure contacting live parts;
c) Causing openings that would expose uninsulated high-voltage live parts; or
d) Causing more than a ±25 percent change in sensitivity.
The force is to be applied by means of a 1/2-inch (12.7-mm) diameter steel hemisphere. Any openings
that occur during application of the force are to be evaluated according to the requirements specified in
7.1.9 and 7.1.10.
54.1.1 The external enclosure of a product containing only low-voltage power-limited circuits is to be
subjected to this test using a 10 pounds-force (44.5 N).
54.1.2 The external enclosure of a product containing high-voltage circuits shall withstand an impact of 5
foot-pounds (6.78 J) without:
a) Permanent distortion to the extent that spacings are reduced below the values specified in
Spacings, General, Section 21;
b) Transient distortion that results in the enclosure contacting live parts, and without causing
openings that expose uninsulated high-voltage live parts; or
c) Causing more than a ±25 percent change in sensitivity.
The impact is to be applied by means of a solid, smooth, steel sphere 2 inches (50.8 mm) in diameter and
weighing approximately 1.18 pounds (0.54 kg) falling freely from rest through a vertical distance of 51
inches (1.31 m). Any openings resulting from the impact are to be evaluated according to the
requirements in 7.1.9 and 7.1.10.
54.1.3 An enclosure containing only low-voltage power limited parts is to be subjected to this test using
an impact of 2 foot-pounds (2.71 J). The vertical fall shall be 20-13/32 inches (0.51 m).
7.1.9 An opening in the enclosure that will not permit entrance of a 1-inch (25.4-mm) diameter rod shall
be sized and so arranged that a probe, as illustrated in Figure 7.4, cannot be made to contact any
uninsulated live electrical part (other than low-voltage) when inserted through the opening in a straight or
articulated position.
7.1.10 An opening that permits entrance of a 1-inch (25.4-mm) diameter rod may be used under the
conditions described in Figure 7.5.
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