Scribd
Upload
13 views3 pages

Lecture 6

HRC (High Rupturing Capacity) fuses are designed with a ceramic or steatite body, a fuse element made of metal alloys, and filled with quartz powder to extinguish arcs during fault conditions. They operate by melting the fuse element under fault current to open the circuit and quench the arc with silica glass. HRC fuses are reliable, require no maintenance, and are used for protecting transformers, motors, and other high-voltage equipment in industrial power systems.

Uploaded by

lr796099
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
13 views3 pages

Lecture 6

HRC (High Rupturing Capacity) fuses are designed with a ceramic or steatite body, a fuse element made of metal alloys, and filled with quartz powder to extinguish arcs during fault conditions. They operate by melting the fuse element under fault current to open the circuit and quench the arc with silica glass. HRC fuses are reliable, require no maintenance, and are used for protecting transformers, motors, and other high-voltage equipment in industrial power systems.

Uploaded by

lr796099
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 3

HRC (High Rupturing Capacity) fuses:

1. Construction
An HRC fuse consists of:

1. Fuse Body
o Made of high-strength ceramic or steatite.
o Provides mechanical strength and withstands high temperature and pressure
during fault interruption.
2. Fuse Element
o Usually made of silver, copper, or tin alloy.
3. Filling Material
o Quartz powder or silica sand fills the fuse body.
o Absorbs heat and extinguishes the arc quickly.
4. End Caps
o Made of copper or brass, plated with silver.
o Used to connect the fuse to the circuit.
5. Arc-quenching Medium
o Quartz powder turns into a glass-like substance under arc heat, absorbing energy.

2. Working Principle
 Under normal current: The fuse element carries current without overheating.
 Under fault condition:
1. Fault current causes the fuse element to overheat.
2. Element melts and opens the circuit.
3. An arc forms between the melted ends.
4. Quartz powder melts and forms silica glass, quenching the arc.
5. Circuit is isolated safely.

3. Characteristics
 Current-Time Characteristics:
o Inverse time characteristic: Higher fault current → faster operation.
o Accurate and predictable melting times.
 Breaking Capacity:
o Can interrupt very high fault currents (up to 80 kA or more).
 Low Power Loss:
o Minimal heat under rated load.
 High Reliability:
o No maintenance; once blown, must be replaced.

4. Applications
 Protection of:
o Transformers
o Motors
o Capacitor banks
o High-voltage switchgear
 Widely used in:
o Distribution networks
o Industrial power systems
o Short-circuit and backup protection for circuit breakers

You might also like