Spark suppression, Physics

Assignment Help:

Spark suppression:

If we consider a circuit with a large inductance, possibly one using a magnetic relay. At the instant the switch is opened, the current through the coil is changing at maximum rate, therefore the back emf induced in the coil is also at maximum.

This emf is applied to the air gap between the switch contacts and ionises the air, producing a spark which the burns the contacts. This increases their electrical resistance and radiates energy which may cause interference, therefore sparks must be suppressed. Good design of switch contacts can help, but connecting a capacitor in parallel with the switch is the best method of eliminating sparking.

When using a capacitor the energy released by the coil charges the capacitor instead of ionising air. When the switch is closed again the capacitor discharges.


Related Discussions:- Spark suppression

Determine the circuit impedance, An alternating voltage given by v=100sin24...

An alternating voltage given by v=100sin240t volts is applied across a coil of resistance 32 and inductance 100mH. Verify (a) the circuit impedance, (b) the current flowing,

Moment of inertia problem, Does the moment of inertia of a cylinder change ...

Does the moment of inertia of a cylinder change if the direction of the rotation axis is changed, but it still goes through the center of mass?

Illustrate the caesium chloride structure, The Caesium Chloride Structure ...

The Caesium Chloride Structure CsCl structure is basically a simple cubic  lattice with 2 atom basis, where one atom is attached to the lattice point and the other at ( a/2 , a

A lever of the second class, A lever of the second class Use a uniform ...

A lever of the second class Use a uniform wooden bar about 1 m long, 4 cm wide and 5 mm thick. Drill a hole near single end, in the centre of the width dimension. Also drill a

Evaluate the angle between reflected and refracted ray, A monochromatic bea...

A monochromatic beam of unpolarised light is incident on a glass slab. The reflected ray is found to be purely plane polarized. Evaluate the angle between the reflected and the ref

What is eddy current?, The current induced in the conductor due change in ...

The current induced in the conductor due change in magnetic field is called eddy current.we study more about this in electro magnetic laws.

Estimate the amount of heat removed, A cooling drum consists of a (horizont...

A cooling drum consists of a (horizontally) rotating, large stainless steel cylinder. The cylinder has a diameter D and a width of W. The cooling at the inside of the drum is so ef

Illustrates the electric motors, Illustrates the Electric Motors? An el...

Illustrates the Electric Motors? An electric motor is basically the reverse of an electric generator. It is a machine which turns electrical energy - AC from the wall or dire

Draw the symbolic representation of a p-n-p and n-p-n, Draw the symbolic r...

Draw the symbolic representation of a (i) p-n-p, (ii) n-p-n transistor. Why is the base region of transistor thin and lightly doped? With proper circuit diagram, show the biasin

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd