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Medium Voltage

Medium Voltage Thyristors
Phase control medium voltage thyristors optimize direct current switching in electrical systems carrying voltages up to 6.5 kV and currents below 4 kA. These specially designed solid state switches limit conduction losses as voltage increases. Medium voltage thyristors also ensure turnoff times do not increase in line with increases in voltage. By doing that, the thyristors lower risks for commutation failures. Littelfuse medium voltage thyristors perform best when used in series. Applications for the solid state switches include dc–dc converters, DC motor drives, and volt–amp (VAR) compensators.
  • Rated at between 3.2 kA and 6.5 kA
  • Available with silicon capsule diameters from 35 mm to 96 mm
  • Optimized for series operation in electrical systems with voltage ratings up to 6.5 kV and current ratings less than 4 kA
  • Maximum power handling capacity achieved at line frequencies below 400 Hz
  • Patented distributed gate architecture ensures excellent switching performance over wide ranges of voltages and currents
  • Engineered to achieve optimal balance between conduction losses, turnoff time, and power-handling capacity
  • Can be used in parallel
  • Predictable fast turnoff prevents commutation failure

Medium Voltage Parts

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Medium Voltage Information Center

Medium voltage fuses are applied quite differently than fuses rated up to 600 V. The biggest difference is that medium voltage fuses are not intended to provide overload protection. They should only be applied in situations where it will not be required to open small overcurrents. Medium voltage fuses offer a much wider range of system voltages, thereby resulting in a correspondingly large number of fuse voltage ratings.

For questions, contact our Technical Support and Engineering Services Group at 1-800-TEC-FUSE (1-800-832-3873).

 

Littelfuse medium voltage fuses are silver element, silica sand, nonexpulsion design, current-limiting type devices. When properly applied, they are designed to carry their nominal current rating continuously without fatigue failure. This means that the fuse will not age, become brittle, or deteriorate under the most severe duty cycling.

When talking current-limiting medium voltage fuses, there are two basic types: general purpose and back-up. General purpose fuses have the ability to interrupt both large and small short-circuits down to currents which would cause the fuse to open within one hour. They are used to provide short-circuit protection for transformers, switchgear, and similar equipment.

Backup fuses are designed to protect only against high fault currents and must be used in series with equipment which provides the circuit’s required overload and low value short-circuit protection.

Medium voltage E-rated fuses are considered general purpose fuses. Their mounting dimensions permit them to be installed in a wide variety of medium voltage switches, in pad-mounted transformers, and at other similar locations. R-rated MV fuses are specifically designed to provide short-circuit protection for medium voltage motor controllers and associated equipment.

Download the Littelfuse white paper on Selecting and Applying Medium Voltage Fuses.