POWR-GARD™ Power Fuse Fuseology Catalog - Littelfuse - #1

^ Littelfuse

Introduction

Fuseology provides the information needed to choose the correct types of Littelfuse POWR-GARD® fuses for most applications. Definition of Terms is followed by Overcurrent Protection Fundamentals. If there are any questions or if additional data is needed for a specific use, Littelfuse application engineers may be reached at 1-800-TEC-FUSE (1-800-832-3873).

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Definitions........................................................................................................137-141

Overcurrent Protection Fundamentals (Fuses and how they work) Index..........142

Why Overcurrent Protection...........................................................................142

What is Quality Overcurrent Protection.........................................................142

Overcurrent Types and Effects.......................................................................142

Fuse Characteristics (600 volts and below)..................................................143

Time-current Characteristic.......................................................144-145

Peak Let-through Charts...........................................................146-147

Fuse Ampere Ratings...............................................................147-148

Fuse Dimensions...............................................................................147

Fuse Coordination (Developing a Selective System)............................148-149

Component Short-circuit Protecting Ability....................................................149

UL/CSA Fuse Classes and Their Application ..............................................150-151

Fuses for Specific Applications (600 volts and below) Index..............................152

Protecting Service Entrance and Feeder Conductors...................................152

Main Services and Feeders...........................................................................152

Motor and Motor Branch-Circuit Protection...................................................152

Motor Overload Protection (running overcurrent)..................................153-155

Motor Feeder (100% motor Load) Protection over 600A..............................155

Motor Branch Circuit Protection over 600A...................................................155

Motor Controller (Starter) Protection over 600A............................................155

Control Transformer Protection..............................................................155-156

Cable Short-circuit Protection (Cable Limiter Application)....................156-157

Primary Fusing With Secondary Fusing........................................................156

Secondary Fusing of Transformers................................................................156

Lighting Fixture Protection.............................................................................156

Street Lighting and Other Weatherproof Overcurrent Protection..................156

Semiconductor and Solid-state Device Protection........................................157

Effect of Ambient Temperature on Fuses......................................................157

Medium Voltage Protection (2400 volts to 25.5 kV).......................................158-161

Motor Protection Tables .................................................................................162-164

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