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Zorluk: KolayProtective Devices

A standard glass cartridge fuse is rated for a continuous operating current of 3 A3\text{ A}. What occurs within this protective device if an electrical short circuit causes a sustained current of 10 A10\text{ A} to flow through it?

  1. A
    The internal element temporarily flexes open and automatically snaps closed once the overload clears.
  2. The internal metal element overheats and melts, creating an open circuit that permanently stops current flow.Cevap
  3. C
    The internal element increases its electrical resistance to convert the extra current into additional supply voltage.
  4. D
    The device alters its polarity to force excess electron flow back toward the power source.

Cevap

The internal metal element overheats and melts, creating an open circuit that permanently stops current flow.
A fuse is a one-time sacrificial protective device wired in series with a load. When the circuit current (10 A10\text{ A}) exceeds the rated threshold (3 A3\text{ A}), resistive heating (I2RI^2R) rapidly raises the temperature of the internal metal link past its melting point. The link separates, creating an open circuit (infinite resistance) that permanently halts current flow to prevent wiring damage or fire.

Adım Adım Çözüm

1
Identify the type and rating of the protective device.
The device is a standard cartridge fuse rated for 3 A3\text{ A}.
Determining the device type establishes whether it is a one-time sacrificial device or a resettable mechanism.
2
Compare the actual fault current to the device's rated current.
The fault current of 10 A10\text{ A} significantly exceeds the 3 A3\text{ A} rating.
Current passing through the fuse element generates heat proportional to I2RI^2R (P=I2RP = I^2R).
3
Determine the physical response of the fuse element under this overcurrent condition.
The excessive current heats the thin metal wire or strip beyond its melting point, burning it open.
Melting breaks electrical continuity, producing an open circuit with infinite resistance that stops all downstream current.

Anahtar Kavram

Operating principle of a standard overcurrent fuse
Tahmini Süre:45s
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Konular

Protective Devices

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