Fuses are often viewed as simple components, but they have a complex interplay of characteristic parameters and are subject to fascinating laws that govern their behavior. These discrete devices play a critical role in protecting electrical systems against overcurrents, and delving deeper into their fascinating world reveals their true complexity. Backup can permanently conduct at maximum current without breaking the circuit.
Fuse properties and parameters
Fuses are important components in electrical systems. They provide important protection against overcurrents and ensure the safety and reliability of our devices and infrastructure. To choose the right fuse for a specific application, it is important to know the characteristic parameters of fuses.
speed
The speed at which the fuse trips depends on the amount of current flowing through the circuit and the type of material the fuse is made of. The operating time of the fuse is not a fixed range, but decreases as the current increases. The operating time of fuses has different characteristics in relation to current fuses, being called fast or delayed depending on the response time to an overcurrent condition. Typically, a fuse takes twice its rated current to trip in 0.1 second, and a slotted fuse takes twice its rated current to trip in 10 seconds.
I2T Value
interrupt capacity
rated voltage
voltage drop
Stress reduction
Safety materials
Security laws
Magnetic circuit laws
It states that the laws governing the constant flow of electricity in a circuit can be easily changed. To be immediately applicable to the Magnetic Circuit . Therefore
Magnetomotive driving force = flux x reluctance
F = ΦxS
Exactly corresponds to electromotive force = current x resistance
Reluctance = (Length/Area) x (1/Permeability)
= l/Aµ
For a magnet with a uniform cross-sectional area that exactly matches
Resistance = (Length/Area) x (1/Conductivity)
It is often convenient to calculate in unit dimensions. We then have
mmf per unit length = flux x reluctance per unit length
= (flow/area) x (l/permeability)
= flux density x (l/permeability)
Magnetic field intensity H = B/µ
This matches exactly,
For a material with uniformly distributed flow and length l, the total mmf is equal to the mmf per unit length xl
i.e. F=Hl or AT=Hl
By dealing with a Magnetic Circuit where the flux must pass through several parts in a matter of seconds, the methods used to deal with electrical circuits in series can be applied immediately, the total reluctance being the sum of the values of the various parts. Normally, the importance of reluctance is only significant to the extent that it allows determining the mmf necessary to produce a given flow in the circuit. It is often the easiest method to determine this total mmf value by adding together the mmf values needed to produce the change in the various parts of the circuit. This is equivalent to calculating the total voltage drop in an electrical circuit by adding the voltage drop values across multiple components.
Thus, the total value of the mmf around a complete magnetic field is given by
AT (or) F = ∫Hdl
Or if the circuit consists of several homogeneous parts, each of which has a uniform cross section and length 1 L 2, etc.
total mmf F (or) AT = Σ Hl = H 1 1 1 +H 2 I 2 +….
= Φ (p 1 +S 2 +….)
If the values of the area and permeability of the different parts of the circuits are A 1 μ 1 etc. becomes all MMF
AT (or) F = (B 1 /μ 1 )i 1 + (B 2 /μ 2 )i 2 +…..
Where B 1 =Φ/A 1 etc.
Occasionally it is convenient to express the basic law of the magnetic circuit in form.
Flux = magnetomotive force x permeance
Permeability is nothing more than the reciprocal of Reluctance to interact for parallel paths, and total permeance is the sum of the values of the individual courses.
The main difference between electrical and magnetic calculations arises from the fact that the resistance of an electrical circuit does not directly depend on the value of the reluctance of a magnetic substance, but to a large extent on the value of the flux passing through it.