Fuses Sizes and Characteristics? 1

[ycliff]

Looking for a reference on fuse sizes and fuse characteristics? ie: what does 200E or 45R mean? Does this describe the tcc, interrupting rating and continuous rating, voltage rating...etc?

 

[vic3fan]

Try

http://www.sandc.com

and see the technical docs they have posted there.

 

[rbulsara]

Visit Bussman, Ferraz-shawmut, S&C etc.'s websites and/or contact their reps to get some application literature. Yes they have distinct TCCs and recommended applications.

For example, E rated fues are generally recommended for feeder and transformer protection. R rated fuses are intended for MV motor protection. But in the end you need to compare TCC's to suit your particular set up. E rated MV fuses in general opens within five minutes if the current exceeds 200% of their E rating.

 

[cuky2000]

These two types of fuses, R and E, are both MV current limiting fuses with the following characteristics:

R-Rated designator signifies the fact that the fuse is built with a rejection feature that consists of grooves or notches provided in either the fuse ferrule or blade, depending on the size involved with nonrenewable cartridge-type available in either the single- or dual-element construction that meet the following requirements:
• The fuse will safely interrupt all currents between its minimum and maximum interrupting ratings.
• The fuse will melt in a range of 15 to 35 seconds at a value of 100 times the “R’ number (ANSI C37.46).
Typical Application: back up used in conjunction with medium voltage motors and motor controllers that are not capable of interrupting high magnitudes of fault current.
_{NOTE: The current-forcing action of current-limiting fuses during interruption produces transient overvoltage on the system, which may require the application of suitable surge-protective apparatus for proper control. The duty imposed on surge arresters can be relatively severe and should be carefully considered in selecting the equipment to be applied.}


E-Rated are general-purpose current limiting fuses. The E-rating defines the melting-time-current characteristic of the fuse. The ratings are used to allow electrical interchangeability among different manufacturers. For E-rating, the following condition must be met:
• The current responsive element shall melt in 300 seconds at a rms current within the range of 200% to 240% of the continuous current rating of the fuse unit (ANSI C37.46).
• The current responsive element above 100 amperes shall melt in 600 seconds at a rms current within the range of 220% to 264% of the continuous current rating of the fuse unit (ANSI C37.46).
Typical Applications:
o Transformer & Feeder Protection:
o Potential transformer & Small units:
o Full range Protection: Capable of interrupting all currents from the rated interrupting rating down to the minimum continuous current that causes melting of the fusible element protection in accordance with ANSI C37.40.
_{NOTE: This type of fuse is not intended to provide protection against low-magnitude overload currents, since it can reliably interrupt only currents above approximately twice its continuous rating.}