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

Nuclear reactions, estimation of nuclear fusion on basis of liquid drop mod...

estimation of nuclear fusion on basis of liquid drop model

Define wave length, Define Wave Length Wave Length : The distance trav...

Define Wave Length Wave Length : The distance travel by a wave during the interval in which the particle of the medium done on vibration is called wavelength

Why the centre of newtons rings pattern appears dark, Q. Why the centre of ...

Q. Why the centre of Newton's rings pattern appears dark? The thickness of the air film becomes zero at the point of contact of lens L with glass plate P. Therefore there is no

How fast are the electrons moving - magnetic field, Electrons travelling at...

Electrons travelling at right angles to a magnetic field experience a force of  8.3 x 10 -13 N when they are in a magnetic field of 6.2 x 10 -1 T. How fast are the electrons

What happen when ultraviolet light shown on the zinc plate, A zinc plate is...

A zinc plate is attached to the knob of a negatively charged electroscope.  What will occur to the leaves of the electroscope when ultraviolet light is shown on the zinc plate

Rectangular plate of the similar mass breadth r , A disc of mass m and radi...

A disc of mass m and radius R is attached to a rectangular plate of the similar mass breadth R and length 2R . Find moment of inertia of this system about diameter of disc. They ar

Rainstorm, why wouldn''''t you be electrocuted if you walked under an elect...

why wouldn''''t you be electrocuted if you walked under an electric transmission line during a rainstorm?

V-i characteristics of constant current source, V-I  Characteristics  ...

V-I  Characteristics  of  Constant  Current  Source A  source  which  has  high  internal resistance  (or  impedance)  as  compared  to  load  resistance  (or  impedance)  i

Hookes law, Hooke's law (R. Hooke): The stress applied on any solid is...

Hooke's law (R. Hooke): The stress applied on any solid is proportional to the strain it generates in the elastic limit for that solid. The constant of that proportionality is

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