Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations LittleInch on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

PT secondary fuse selection 2

Status
Not open for further replies.

SJBatTCE

Electrical
Joined
Oct 8, 2001
Messages
41
Location
US
Can anyone explain the basis for selecting a PT fuse(or VT as some may call it) for the secondary winding?

Thanks. To whoever answers this... YOU RULE! Heh
 
Fuses are placed in the VT secondary circuit to guard against the secondary of the VT being shorted if there is a fault in the secondary circuit, between the fuse and the connected equipment.

The rating of the fuse should ideally be less than the thermal burden of the VT being protected. Take the themal burden divided by the rated secondary voltage to get the fuse rating. Non time delay fuses are generally used for this application.

It is best to place the fuses in the VT terminal box, but they are most commonly placed in the 3-phase junction box, normally mounted on the pedestal of the center phase.

If you have a VT with a tapped secondary, the fuse should be placed in the non-polarity lead, i.e. you don't need to have a fuse on each terminal.

Hope this helps.

 
There's your star,... YOU RULE (I always keep my promises)
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top