为什么poe供电不稳定,poe供电不稳定会不会导致网络不稳定

现在还有好多人不知道为什么poe供电不稳定，接下来我们小编就来分享一下。

为什么poe供电不稳定

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 2em; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">很多朋友多次问到poe供电是否稳定？poe供电用什么线缆好？为什么使用poe交换机供电摄像机还是没有显示?、、等等问题，其实这些都跟POE供电功率损耗相关的，在项目中很容易忽略。这里面刚好有一位专业做poe相关的朋友给我们投稿，很好的说明了poe供电中功率损耗问题，我们一起来看了解下。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; text-align: center; letter-spacing: 2px; font-size: 15px;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">一、什么是poe供电

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">PoE指的是在现有的以太网Cat.5布线基础架构不作任何改动的情况下，在为一些基于<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">IP的终端(如IP电话机、无线局域网接入点AP、网络摄像机等)portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">传输数据portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">的同时，还能为此类设备提供portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">直流供电portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">的技术。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">PoE技术能在确保现有结构化布线安全的同时保证现有网络的正常运作，最大限度地降低成本。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">一个完整的PoE系统包括portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">供电端设备portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">和<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(0, 0, 0);">受电端设备portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">两部分。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; text-align: center; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">供电端设备(PSE)：portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">支持POE功能的以太网交换机、路由器、集线器或者其他网络交换设备。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">受电端设备(PD)：portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">在监控系统中主要就是网络摄像机(IPC)。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; text-align: center; letter-spacing: 2px; font-size: 15px;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">二、poe供电标准

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">2003年设立的国际标准portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">IEEE802.3afportant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">要求PSE能达到15.4W的输出功率，而到达受电设备的功率是12.95W，电源损耗为<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">2.45W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">2009年设立的国际标准portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">IEEE802.3atportant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">则要求PSE能达到30W的输出功率，到达受电设备的功率是25.5W，电源损耗为4.5W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">随着时间的推移这两种标准的功率已经不能满足现在新的更大功率的PD的供电要求。因此最新的国际标准IEEE802.3bt有两种要求：

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; text-align: center; box-sizing: border-box !important; overflow-wrap: break-word !important;">IEEE国际标准参数表

<p style="text-align: center; margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">第一种：portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">其中一种是要求portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">PSE能达到60W的输出功率portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">，到达受电设备的功率是51W（从上表可知这个是最低的数据），<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">电源损耗为9W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">第二种：portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">则要求portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">PSE能达到90W的输出功率portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">，到达受电设备的功率是71W，电源损耗则为19W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">由上面的标准可以知道随着供电功率的增大，功率的损耗并不是按照供电功率成比例的损耗，而是损耗越来越大，那么究竟PSE在实际应用中的损耗怎样才能计算出来呢?

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; text-align: center; letter-spacing: 2px; font-size: 15px;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">三、poe供电损耗

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">那么我们先看一下初中物理对导线功率的损耗是怎么计算的。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">焦耳定律是定量说明传导电流将电能转换为热能的定律。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">内容是：portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">电流通过导体产生的热量跟电流的二次方成正比，跟导体的电阻成正比，跟通电的时间成正比。也就是计算过程中产生的员耗。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">焦耳定律数学表达式：portant; overflow-wrap: break-word !important; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px;">Q=I²Rt<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">（适用于所有电路）其中的Q就是损耗的功率P，I是电流，R是电阻，t是时间。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">在实际使用中由于PSE和PD是同时工作的，所以损耗和portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">时间无关portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">。得出结论就是在POE系统中网线的损耗功率与电流的二次方成正比，与电阻的大小成正比。简单来说为了减少网线的功耗我们要尽量使导线的<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);">电流变小portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">，让网线的<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">电阻变小。其中电流变小的意义特别重要。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">那么我们来看一看国际标准的各个具体参数是多少：

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">在IEEE802.3af标准中网线的电阻是20Ω，要求的PSE输出电压是44V电流是0.35A，损耗功率P=0.35*0.35*20=2.45W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">同理在IEEE802.3at标准中网线的电阻是12.5Ω，要求的电压是50V电流是0.6A，损耗功率P=0.6*0.6*12.5=4.5W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">这两种标准使用这种计算方法都没有问题。但是当到了IEEE802.3bt标准的时候就不能这样计算了，如果电压是50V要达到60W的功率必须要1.2A电流，此时损耗功率为P=1.2*1.2*12.5=18W,减去损耗到达PD设备的功率只有42W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; text-align: center; letter-spacing: 2px; font-size: 15px;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">四、poe供电损耗的原因

<p style="text-align: center; margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px;">那么到底是什么原因呢？

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px;">

<p style="text-align: left; margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px;">与实际要求达到的51W少了了9W的电能。那么到底是什么原因导致计算错误。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px;">我们再来观察这个数据图最后一列，仔细观察一下原来IEEE802.3bt标准中的电流仍然是0.6A，再看供电的双绞线可知，是用的portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">四对双绞线供电portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-align: justify; text-indent: 30px;">（IEEE802.3af，IEEE802.3at是用两对双绞线供电）这样一来就可以把这种方式看做并联电路，整个电路电流是1.2A，但总的损耗是两对双绞线供电时损耗的两倍，

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">所以损耗portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">P=0.6*0.6*12.5*2=9W,portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">相对于2对双绞线来说这种供电方式节省了9W的电能，所以使得供PSE在输出功率只有60W的情况下使得PD设备接收到的功率能够达到51W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">因此我们在选用portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">PSE设备portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">的时候一定要注意尽量portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">减小电流portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">，portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">增大电压portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">，否则容易导致电能损耗过大，单从PSE设备的功率感觉是可以用的，但到实际中是不可用的。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; text-align: justify; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">举例

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">某个PD设备（比如摄像机）需要12V 12.95W才能使用，如果使用12V2A的PSE，输出功率为24W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">在实际使用中，当电流为1A时，损耗P=1*1*20=20W。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">当电流为2A时，损耗P=2*2*20=80W，

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">此时电流越大损耗越大，大部分的功率都已经损耗完了，显然此PD设备无法接收到PSE输送的电能，摄像机就会出现供电不足，无法正常工作。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">这个问题也是实际中常见的，很多情况下看似供电功率很大，足够用，却没有算损耗，结果摄像机因为供电不足无法正常工作，而总是找不到原因。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; box-sizing: border-box; clear: both; min-height: 1em; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; text-align: center; letter-spacing: 2px; font-size: 15px;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">五、poe供电电阻

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">当然以上所说的是当供电距离为100米时网线的电阻，这是最大供电距离下的可用功率，但如果实际使用时的供电距离比较小，比如只有10米，那么电阻就只有2Ω，相应的损耗就只有100米的10%的损耗，所以选用PSE设备的时候充分考虑到实际使用的情况也是很重要的。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; text-indent: 0em; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">超五类双绞线各种材质网线100米的电阻：

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">1.铜包钢网线：75-100Ω

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">2.铜包铝网线：24-28Ω

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">3.铜包银网线：15Ω

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">4.铜包铜网线：42Ω

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(217, 33, 66);"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; font-size: 15px; letter-spacing: 2px; text-indent: 30px;">5.无氧铜网线：9.5Ω

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">可以看得出，越好的线缆，电阻最小，根据公式Q=I²Rt，也就是供电过程中损耗的功率最少，所以这就是为什么要用好线缆的原因，portant; overflow-wrap: break-word !important;">建议最好用六类线较稳妥些。

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; text-indent: 28px; box-sizing: border-box !important; overflow-wrap: break-word !important;">

<p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; clear: both; min-height: 1em; color: rgb(51, 51, 51); font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif; font-size: 17px; letter-spacing: 0.544px; text-align: justify; white-space: normal; box-sizing: border-box !important; overflow-wrap: break-word !important;">portant; overflow-wrap: break-word !important; color: rgb(84, 84, 84); font-size: 15px; letter-spacing: 2px; text-indent: 30px;">上面我们说到了，损耗功率公式，<strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; overflow-wrap: break-word !important;">Q=I²Rt，要想poe供电从PSE供电端到PD受电设备之间损耗最少，需要电流最小，电阻最小，才能使整个供电过程中效果最好。

以上就是我们整理的为什么poe供电不稳定,poe供电不稳定会不会导致网络不稳定，不知道你从中找到你需要的信息了吗 ？如果你还想了解更多这方面的信息，安防网往后会继续推荐为什么poe供电不稳定,poe供电不稳定会不会导致网络不稳定相关内容。