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

Illustrate the phasor diagram for an ideal transformer, Draw the phasor dia...

Draw the phasor diagram for an ideal transformer on no-load. (a) A 500 V/100V, single-phase transformer takes a full load primary current of 4A. Neglecting losses, Verify

Name the types of photoelectric cells, Q. Name the types of photoelectric c...

Q. Name the types of photoelectric cells? The photo electric cells are of three kinds: A) Photo emissive cell B) Photo voltaic cell and C) Photo conductive cell.

What mass of coal can the barge carry in freshwater, An open barge has the ...

An open barge has the dimensions 22x40x12m. If the bargeis made out of 4.0-cm-thick steel plate on each of its four sides and its bottom, what mass of coal can the barge carry in f

Ice melting, I want to know about renewal time, such as the Greenland Ice s...

I want to know about renewal time, such as the Greenland Ice shelf melting. How much does it cost to have the equations and to have this explained please?

Explain phenomenon of scattering, Some phenomenon based on scattering: (...

Some phenomenon based on scattering: (i) Sky looks blue because of scattering. (ii)  At the starting time of sunrise or sunset sun looks reddish. (iii) Danger signals are

Thermal Energy, A 2350-kg granite tombstone absorbs 2.8 x 107 J of energy f...

A 2350-kg granite tombstone absorbs 2.8 x 107 J of energy from the Sun to change its temperature from 5.0°C at night to 20.0°C during an autumn day.

What is henrys the inductance of the coil, A circular coil has a 12.8cm rad...

A circular coil has a 12.8cm radius and consists of 29.0 closely wound turns of wire. An externally produced magnetic field of magnitude 2.23 mT is perpendicular to the coil. (a) i

Explain law of conservation of momentum, LAW OF CONSERVATION OF MOMENTUM. ...

LAW OF CONSERVATION OF MOMENTUM. "The total linear momentum of an isolated system always constant"                                  OR  "If there is no external force ap

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