IEC 60287-2-1 2015: 电缆热阻计算

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"IEC 60287-2-1 2015标准是关于电动电缆电流额定值计算的一部分，特别是热电阻的计算。该标准详细规定了如何评估和计算电力电缆的热性能，确保其在运行时的安全性和效率。" IEC 60287-2-1是国际电工委员会（International Electrotechnical Commission, IEC）发布的一个重要标准，它属于IEC 60287系列的一部分，专注于电缆的热电阻计算。2015年版为第二版，对之前的版本进行了更新和修订，旨在提供最新的指导原则，以便于工程师和设计师准确计算电缆的载流能力。 在电力系统中，电缆的热性能是至关重要的，因为它直接影响到电缆的载流能力、寿命以及整个系统的安全。IEC 60287-2-1标准详细阐述了如何计算电缆的热电阻，这是一个关键参数，因为它关系到电缆在运行过程中能否有效地散发热量。热电阻的计算涉及以下几个方面： 1. **环境条件**：包括温度、通风条件和安装位置等因素，这些都会影响电缆的散热。 2. **电缆结构**：电缆的材料、截面积、绝缘层、护套以及多芯电缆的配置都会影响热阻。 3. **载流密度**：电缆的载流能力与其横截面积和导体材料的电导率有关。标准提供了计算不同工作条件下的最大允许电流的公式。 4. **热平衡**：考虑电缆在长时间运行时的热稳定状态，包括启动、停止和连续负载情况下的热效应。 5. **安全因素**：为了防止过热导致的电缆损坏或火灾风险，标准设定了安全裕度，以确保电缆在设计载流下不会过热。 6. **计算方法**：标准提供了详细的计算步骤和公式，以确定在特定环境和安装条件下的电缆热电阻。 应用IEC 60287-2-1标准时，工程师需要考虑所有相关因素，并根据标准提供的方法进行详细的分析和计算。这对于电力系统的设计、规划和维护至关重要，确保电缆能够在各种条件下安全、可靠地运行。 IEC 60287-2-1是电力行业中的一个关键工具，它提供了计算电缆热性能的统一标准，有助于保证电气系统的稳定性和安全性。对于从事电缆设计、安装和维护的专业人士来说，理解和掌握这个标准的内容至关重要。

IEC 60287-2-1-2015 Thermal resistance – Calculation of thermal resistance.pdf

2022-12-20 上传
IEC 60287-2-1-2015 Thermal resistance – Calculation of thermal resistance.pdf

thermal resistance calculation

2019-02-17 上传
a method for thermal resistance calculation. just for engineer

Thermal Design Of Electronic Equipment - Part 1

2010-03-17 上传
Thermal Design Of Electronic Equipment - Part 1

C++写Mr. Wor's router at home is broken again. After some repairs, he needs to reconnect the Ethernet cables to the router. It is known that Mr. Wor's router has n ports, and there are n Ethernet cables. Then, Mr. Wor will sequentially insert the i -th Ethernet cable to the i -th port, for all i from 1 to n . However, due to Mr. Wor's mysterious actions, the first m cables were not inserted into their designated ports, but were inserted into m ports uniformly at random. For the remaining cables, when cable i is being inserted, if port i is not occupied, then cable i will be inserted into port i . Otherwise, cable i will be inserted into a randomly chosen unoccupied port. Mr. Wor wants to know the probability that the last cable, cable n , is plugged into port n . Input Only one line contains two integers n,m(1≤n≤10,0≤m≤n) , denoting the number of cables and the number of cables which was inserted randomly. Output Print the probability in one line. Your answer is considered correct if the relative or absolute error is less than or equal to 10−6 . Example inputCopy 3 1 outputCopy 0.5000000000

2023-05-26 上传
3.若插头数量小于等于m，则第i个插头有i-1种选择，因此f[i][j] += f[i - 1][j] * (i - cnt - 1)。 4.否则，第i个插头有两种选择：插到空闲的位置或者插到已经有插头的位置。 5.如果插到空闲位置，有i-cnt种选择；...

用c++解决Andrew is working as system administrator and is planning to establish a new network in his company. There will be N hubs in the company, they can be connected to each other using cables. Since each worker of the company must have access to the whole network, each hub must be accessible by cables from any other hub (with possibly some intermediate hubs). Since cables of different types are available and shorter ones are cheaper, it is necessary to make such a plan of hub connection, that the maximum length of a single cable is minimal. There is another problem - not each hub can be connected to any other one because of compatibility problems and building geometry limitations. Of course, Andrew will provide you all necessary information about possible hub connections. You are to help Andrew to find the way to connect hubs so that all above conditions are satisfied. Input The first line contains two integer: N - the number of hubs in the network (2 ≤ N ≤ 1000) and M — the number of possible hub connections (1 ≤ M ≤ 15000). All hubs are numbered from 1 to N. The following M lines contain information about possible connections - the numbers of two hubs, which can be connected and the cable length required to connect them. Length is a positive integer number that does not exceed 106. There will be no more than one way to connect two hubs. A hub cannot be connected to itself. There will always be at least one way to connect all hubs. Output Output first the maximum length of a single cable in your hub connection plan (the value you should minimize). Then output your plan: first output P - the number of cables used, then output P pairs of integer numbers - numbers of hubs connected by the corresponding cable. Separate numbers by spaces and/or line breaks.

2023-06-03 上传
这是一道最小生成树问题，可以使用Prim或者Kruskal算法来解决。下面是使用Kruskal算法的C++代码实现： ```cpp #include ...1 2 1 1 3 2 3 4 3 2 4 4 1 4 5 ``` 输出样例： ``` 4 3 1 2 1 3 3 4 ```

查找手机是否支持DP ALT MODE的网站

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2. DisplayPort 官方网站 - https://www.displayport.org/product-category/cables-adaptors/ 3. Anker PowerLine+ USB-C to HDMI Cable - ...

Error (209014): CONF_DONE pin failed to go high in device 1. Make sure all communication cables are securely connected, select a different device, check the power on the target system, or make sure all nCE pins are connected to GND. The Intel FPGA Knowledge Database contains many articles with specific details on how to resolve this error. Visit the Knowledge Database at https://www.altera.com/support/support-resources/knowledge-base/search.html and search for this specific error message number.

2023-07-13 上传
1. 确保所有通信电缆连接牢固，包括JTAG电缆和编程电缆。 2. 检查目标系统的电源，确保其正常工作。 3. 确保所有nCE引脚连接到GND。这些引脚是FPGA上的片选引脚，需要连接到地。 4. 如果仍然无法解决问题，请访问...

No devices were found

2023-08-17 上传
{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v92^chatsearchT0_1"}}] [.reference_item style="max-...

Conductor Properties

2024-09-03 上传
2. **Thermal Conductivity**: Although not directly related to electrical conductivity, conductive materials also tend to have high thermal conductivity because electrons transfer heat as they move. ...

Discuss the Ethernet and its two types in detail with a diagram. Classic Ethernet Physical Layer, Classic Ethernet MAC Sublayer Protocol, CSMA/CD with Binary Exponential Backoff, Switched Ethernet

2023-05-29 上传
Classic Ethernet uses coaxial cables as the communication medium and has a maximum data rate of 10 Mbps while Switched Ethernet uses twisted-pair or fiber optic cables and has a maximum data rate of ...
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