Fuse trouble

[fauxfly]

Morning guys

I got 400 amp fused disco on a chiller. My problem is I think the cutler-hammer slide in style fuse clips are sprung and when I draw my FLA for extended periods I'm generating a lot of heat at the connection point and blowing my fuse... not through an overcurrent situation but a thermal situation from the ambient area around the fuse clip itself. I had my power monitoring equipment on for the W/E and this never shows a over current event. I dont have a way to record temp over time though.

I'm wondering if there is a style of fuse at the 400 amp level which does'nt have the thermal feature included. I'm useinf a FRN-R-400 now and I dont think I need this. Eventually I'll have to replace the clips or the whole disco with somthing else.


What do you guys think... Does a fuse like this exist.

Thanks

Steve

 

[tlaidman]

They used to make a clamp that could be installed and tightend over the fuse clip to tighten the clip. You might try using them

 

[mivey]

They used to make a clamp that could be installed and tightend over the fuse clip to tighten the clip. You might try using them

See this thread:
http://forums.mikeholt.com/showthread.php?t=101577

[edit:
and this: http://host1.publiquik.com/bussmann_web/family.cgi?familyUid=414 ]

 

[brian john]

Do a FOP get new fuse clips and use fuse clamps till the clips arrive.

http://www.connex-electronics.com/?url=/html/products/bussmann/buss_accessories_main.html

 

[weressl]

Morning guys

I got 400 amp fused disco on a chiller. My problem is I think the cutler-hammer slide in style fuse clips are sprung and when I draw my FLA for extended periods I'm generating a lot of heat at the connection point and blowing my fuse... not through an overcurrent situation but a thermal situation from the ambient area around the fuse clip itself. I had my power monitoring equipment on for the W/E and this never shows a over current event. I dont have a way to record temp over time though.

I'm wondering if there is a style of fuse at the 400 amp level which does'nt have the thermal feature included. I'm useinf a FRN-R-400 now and I dont think I need this. Eventually I'll have to replace the clips or the whole disco with somthing else.


What do you guys think... Does a fuse like this exist.

Thanks

Steve

Since you have not given any time/curren relationship, this is just poking in the dark.
HVAC compressors have a long and high inrush current and often operate in the high load state close to before it unloads. You can use an IR scneer or an insulated temperature probe to see if you actually have a 'hot clip'. It usually takes getting as hot to show discoloration to interefere with the fuse's thermal profile.

FRN-R is a 250V rated fuse you sure you have a 208V 400A rated compressor? What is the AC unit manufacturers recommended minimum size and type fuse?

 

[fauxfly]

Thanks weressel

Yes I do have a 3phase 208 volt compresser motor. I do see a bit of discoloration on the clips and on the fuse blades themselves. I'm trying to replace the fuse clips/holders themselves. Cutler-hammer's website is a little clumsy, I'll find what I need eventually.

Thanks guys

Steve