Fuse switch sizing for a vsd

[westward10]

40A may well be okay but may not. As others have stated you need hard spec from the vsd.

 

[davesparks]

Yes we have sized that at approximately 10mm. And we have identified that the existing fuse switch type CM-UT 100A-415v can be reused, Wewould like to provide an estimated protection size, motor rated fuse gM so we have something to work with.

Thanks

Surely you need to know the rating of the fuse before you calculate the cable size, not after?

 

[snowhead]

A motor rated fuse is the last thing you want protecting a VSD.
The VSD protects the motor, the fuses in the supply protect the VSD which is an electronic device.
You need fast acting fuses as determined by the VSD manufacturer.
I've just retired and thrown all my VSD manuals out but here's a link to an ABB VSD and the fusing required.
Note, for a 18kw (25hp) they quote JJS50 fuse.
PDF page 32 actual page 22
https://library.e.abb.com/public/cb...04422cc/3AUA489002B5311_ACH400_00_UM_REVE.pdf

 

[MDJ]

Single phase or three phase? Have I missed the answer somewhere?

 

[Rocboni]

ideally Semiconductor fuses req for VSD drives. Is this not taken care of in the control panel?