On one hand, you need current-limiting protection for medium-voltage transformers and distribution systems. On the other, you need short circuit protection for medium-voltage motors and motor controllers. Mersen's line of medium-voltage UL Listed fuses fills the bill with E-rated, R-rated and capacitor fuses.
Current-limiting power fuses are widely used in these applications because they afford excellent over-current protection and noiseless operation, and because they can be used in confined spaces. The amount of damage in the faulted area and the mechanical stress and strain on busway, switches and other apparatus carrying the fault current is proportional to the square of the current and to the length of time the fault persists. By limiting the let through energy at the fault, properly applied current-limiting fuses assist in limiting or preventing
short-circuit damage to busway, circuit breakers, switches, and other electrical components. Current-limiting power fuses are manufactured in ratings ranging from 1kV through 38 kV and in continuous current ratings from 0.5 amperes
through 1200 amperes. Various designs are available for use with motors,transformers, capacitors, and circuit-protection equipment.