Fuses and Links 5

[paulclayton1]

I am a relatively new engineer working in the transmission and distribution of electricity. When preparing wiring schemes i know that electrical equipment is protected by a fuse and link. I know that a fuse blows when the supply exceeds a certain limit but can someone give me a good explanation of what the link is there for.

 

[DanDel]

In most cases a 'link', as in 'fused link' is merely a wire made of similar materials as a fuse, and used for the same purpose, but only in low-voltage applications (maybe <50V).

 

[ruble3]

check this out-

http://www.sandc.com

- then products & tech support for an explanation

 

[ohms]

Normally the fuses are used in the current path to isolate the system, when there be any abnormal / high current. Whereas the Links are generally used in the neutral path just to isolate, where the current flow is very low during normal operating condition, and very high during earth fault conditions. In other words the neutral and earth will be in same potential and no current will flow in the circuit. High current carrying strips are used in links whereas thin wires are used in fuses.

In simple, Fuses are used to protect the equipment and link are used to isolate the equipment.

 

[busbar]

 
For typical <38kV overhead distribution systems on the North American continent, expulsion fuses are very common. ANSI references are C37.40-series standards.

Literature from one producer of many is…

http://www.cooperpower.com/Products/Components/Fusing/Fusing_expul.asp

http://www.cooperpower.com/library/literature/section.asp?ProductLineID=27

 

[BJC]

All links are fuses, not all fuses are links.
Fuse links when melted open a fuse cutout switch.
Here's an ABB cutout switch.

http://library.abb.com/GLOBAL/SCOT/...CB0B85256E0C007388F2/$File/ICX DB38-631.pdf

Thats a very long link- you can find similar information by googling up "fused cutouts"
Below is another good link -worth gettin if your into T&D.

http://library.abb.com/GLOBAL/SCOT/...BF85256C550053DB0D/$File/Hard.To.Find.6th.pdf

If that one doesn't work google up "ABB, Hard to Find Information About Distribution Systems."

 

[RalphChristie]

BJC - Red star for the last link!

paulclayton1:
Highly recomended files (downloadable) worth a read from Areva (It is the old PRAG-book):

http://www.areva-td.com/servlet/Con...d=1017999014820&tab=Chapters&id=1056536208254

As a last note a just want to say that this site (

http://www.eng-tips.com)

is one of the best places to visit to find some info regarding engineering. Defenitely worth a visit every day. It helped me quite a lot with some problems I've encountered in my workplace.


Best Regards
Ralph