|
| | 以下是对《为什么直流电比交流电电人更厉害？》的回复： | | 共有2人回复 分页: 1 |  芯片级维修： | 引用 加为好友 发送留言 2007-1-4 22:06:00 | 刚好说反了，应该是交流电比直流电厉害（相同电压）
AC is said to be four to five times more dangerous than DC. For one thing, AC causes more severe muscular contractions. For another, it stimulates sweating that lowers the skin resistance. Along that line, it is important to note that resistance goes down rapidly with continued contact. The sweating and the burning away of the skin oils and even the skin itself account for this. That is why it's extremely important to free the victim from contact with the current as quickly as possible before the climbing current reaches the fibrillation-inducing level.
The frequency of the AC has lots to do with the effect on the human body. Unfortunately, 60 cycles is in the most harmful range. At the house voltage frequency, as little as 25 volts can kill. On the other hand, people have withstood 40,000 volts at a frequency of a million cycles or so without fatal effects.
A very little current can produce a lethal electric shock. Any current over 10 ma. will result in serious shock.
Summary
Voltage is not a reliable indication of danger because the body's resistance varies so widely it is impossible to predict how much current will be made to flow through the body by a given voltage.
The current range of 100- to 200-ma, is particularly dangerous because it is almost certain to result in lethal ventricular fibrillation. Victims of high-voltage shock usually respond better to artificial respiration than do victims of low-voltage shock, probably because the higher voltage and current clamps the heart and hence prevents fibrillation.
AC is more dangerous than DC, and 60-cycle current is more dangerous than high-frequency current.
Skin resistance decreases when the skin is wet or when the skin area in contact with a voltage source increases. It also decreases rapidly with continued exposure to electric current.
| | | 芯片级维修： | 引用 加为好友 发送留言 2007-1-6 16:18:00 | | 交流电对人体的损害作用比直流电大，不同频 率的交流电对人体影响也不同。人体对工频交流电要比直流电敏感得多，接触直流电时，其强度达250毫安有时也不引起特殊的损伤，而接触50赫交流电时只要有50 毫安的电流通过人体，如持续数十秒，便可引起心脏心室纤维颤动击导,导致死亡。交流电中28-300赫的电流对人体损害最大，极易引起心室纤维性颤动，20000赫以上的交流电对人体影响较小，故可用来作为理疗之 用。我们平时采用的工频交流电源为50赫，从设计电气设备角度考虑是比较合理的，然而50赫的电流对人体损害是较严重的，故一定要提高警惕，搞好安全用电工作。 | |
上一篇：求助:低压电容补偿三相电流不平衡
下一篇：eps电源的选型方法
来源： 编辑： 日期：2007-1-10 16:17:38
收藏此页到365Key
| |
