R-Rated Series - Medium Voltage Fuses
Brand: Littelfuse, IncR-rated fuses provide required short-circuit protection for medium voltage motors, motor controllers and associated circuitry.
These components have limited ability to absorb the energy of large short circuit currents.
Medium voltage motor controllers contain overload relays which provide both overload protection and locked rotor protection to the motor.
The controllers are also intended to interrupt low value short circuits within the capability of the motor controller. This protects the medium voltage R-rated fuse from sustained over-currents which are less than their minimum interrupting rating.
NEMA Standards for R-rated medium voltage power fuses require that they operate within 15-35 seconds when subjected to an rms current 100 times the 'R' rating.
For example, a fuse with a 2R rating will open within 15 to 35 seconds on an applied current of 2 x 100 = 200 amperes.
Features- Hermetically sealed for use in hazardous locations (add “S” suffix to part number)
- Bolt-in mounting configuration. For hookeye attachment; add ‘W’ suffix to part number.
- Live parts and mounting clips are available for mounting E-rated single, double, and triple barrel fuses. Note, all clips are sold in pairs.
- Power Transformer Protection
- Potential Transformer Protection
- Motor Controller Back-up Protection
- Fused Switches
- Feeder Circuits
Documentation
Data Sheets
Technical Papers
Time Current Curves
- R-Rated Time Current Curve - 2.75kV R-Rated 2R-24R - Melting Time pdf 29 KB
- R-Rated Time Current Curve 2.75kV R-Rated 2R-24R - Clearing time pdf 28 KB
- R-Rated Time Current Curves - 8.25V R-Rated 2R-24R - Clearing Time pdf 44 KB
- R-Rated Time Current Curves - 8.25V R-Rated 2R-24R - Melting Time pdf 44 KB
- R-Rated Time Current Curves 5.5kV R-Rated 2R-36R Clearing Time pdf 66 KB
- R-Rated Time Current Curves 5.5kV R-Rated 2R-36R Melting Time pdf 66 KB