问题 问答题 简答题

什么是隔爆型电气设备?例举隔爆低压开关的几种失爆现象。

答案

参考答案:

具有隔爆外壳的防爆电气设备,该外壳既能承受内部爆炸性气体混合物引爆产生的爆炸压力,又防止爆炸产物穿出隔爆间隙点燃外壳周围爆炸性混合物。

1)设备外壳有裂纹、开焊面积在50平方厘米范围内,凹凸深度超过5mm或因外壳变形影响电气间隙,达不到规定的为失爆。

2)隔爆电气设备外壳内或外表面锈蚀为失爆。

3)隔爆电气设备加工金属表面发现有锈,用棉丝擦拭过后仍留有斑痕并超过有关规定的为失爆。

4)隔爆电气设备紧固件、导电件发现有锈用棉丝擦过后,仍有明显锈斑,并影响强度和导电性能的为失爆。5)隔爆电气设备的门、盖采取正常操作方式打开的为失爆。

阅读理解

阅读理解。

     A lamp is more than a light. Lamps allow the owner to add to the design of a room. They are

very functional and sometimes the only source of light in a room. There are many types of lamps,

and of course they come in many styles and colors to fit anyone's home. Lamps can be soft and

inviting or bright and useful. Floor lamps are often tall, thinly shaped lamps that bring light to a large

area by cupping the bottom of the bulbs and forcing light up. Table lamps tend to force the light

down and out to lighten up a smaller, more private space. But, that doesn't mean that you can't

find a lamp that fits your needs as well as your tastes. In fact, you can even have lamps made to

order to match your desired look.

     But, before you decide to make that decision, check out the lamps in department stores and

specialty stores. While most home improvement stores offer a wide variety of floor lamps, hanging

lamps, and table lamps, you can find an even larger selection in a lighting store. There you will be at

a loss about all the different choices you have. There will be choices in every style imaginable. If you

still can't find what you are looking for, check contents and even the Internet. Specialty stores

nationwide will ship lamps and accessories (配件) to you.

     Adding some extra light to your home may have been your early search when trying to find a

lamp, but you will soon see that there is more to look for in a lamp. The design will fit your home

and the color should match your home. The details on the lamp or lamp shade can even be found

to match your furniture, tables, or other items in your home. Finding a great lamp is a fun adventure

into the world of lighting.

1. The purpose of the passage is ______.

A. to tell us how to choose lamps for our home

B. to inform us of the variety of lamps produced in stores

C. to tell us that different lamps have different usages

D. to show us the great part lamps play in our life

2. According to the author, ______.

A. all the floor lamps are tall and thin

B. table lamps can help you avoid being seen

C. lamps can be attractive in a way

D. none of the lamps will suit you

3. What's the author's attitude towards having a lamp made to order?

A. That's just what he wants to suggest.

B. He suggests seeking lamps in stores.

C. He thinks it a waste of money.

D. He advises making lamps by oneself

4. What should you do if you plan to buy a floor lamp?

A. You should buy a floor lamp at last.

B. You should match the lamp with your room.

C. You should find some accessories to it.

D. You should think of nothing but a floor lamp.

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