Power questions

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milmat1

milmat1

"It Can't Do That !"
Location
Siler City, NC USA
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Controls Engineer
I'm not a power guys by any means. I'm a controls engineer, but we have been asked to quote a VFD system for a customer. My question is regarding the fusing and power distribution. The drives are (2) 400hp and 500hp Yaskawa A1000 series. (675A). The manual calls for 1000 amp time delay fuses.

I cannot find any data on fuse holders for fuses of this size. I found a Mersen part no but no picture, drawings, etc.

When you get into this size / class of fusing and protection. What is the normal procedures ? We have several other machine systems quoted to this same customer and it is important that we do this part as well..
 
milmat1 said:
I'm not a power guys by any means. I'm a controls engineer, but we have been asked to quote a VFD system for a customer. My question is regarding the fusing and power distribution. The drives are (2) 400hp and 500hp Yaskawa A1000 series. (675A). The manual calls for 1000 amp time delay fuses.

I cannot find any data on fuse holders for fuses of this size. I found a Mersen part no but no picture, drawings, etc.

When you get into this size / class of fusing and protection. What is the normal procedures ? We have several other machine systems quoted to this same customer and it is important that we do this part as well..
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Tried Cooper Bussmann?
Their 1,000 page catalogue has everything that just about anyone and their granny can supply.
 
there are 800 A switches 480 vac, 500 hp, that take up to 1200 A fuses
that seems like the max standard
there are larger ones, 1200 A, but not HP rated for some reason, although the kw rating exceeds 600 hp
call a few vendors and see what they say
 
At that size, there are no "fuse holders" in the same sense that you see them on smaller fuses. There are just mounting blocks, because the fuses bolt in.

Also at that size, most drives will have a contactor in the "pre-charge" circuit, so a disconnect up stream of the drive does not need to carry a HP rating, because the switch will close with no load on it, but must be coordinated with the pre-charge so that the contactor is opened before the switch and closed after it by using the proper aux contact interlocking. So in most cases you are better off buying your VFD as a combination unit that comes WITH the fuses and disconnect it requires. When using VFDs here in the US, you need an SCCR listing, and that will have been tested with a SPECIFIC fuse in most cases. If the VFD mfr supplies it as a package, you are assured (in most cases) of getting it right, or at least you get "one throat to choke" if it ends up being red-tagged by an AHJ.
 
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As others said - those fuses bolt on, even in a 1200 amp fused safety switch, you bolt such fuses into them.
 
Thanks Everyone !!


I am looking at the VFD manufacturer supplying a "configured" unit per drive..
Thanks Again, Like I said I am just outside my normal zone here..
 
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