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

#titlemotion.., concept of position and displacement

concept of position and displacement

#title, Ask questiA 1.10×10-2-kg bullet strikes a 0.300-kg block attached t...

Ask questiA 1.10×10-2-kg bullet strikes a 0.300-kg block attached to a fixed horizontal spring whose spring constant is 2100 N/m and sets it into oscillation with an amplitude of 1

Whomehole, What is whomehole and how it

What is whomehole and how it

Explain crohn disease, Explain Crohn disease Crohn's disease:  a chro...

Explain Crohn disease Crohn's disease:  a chronic, recurrent disease characterized by patchy inflammation of any portion of digestive tract from  the mouth to anus.

What are quarter wave plates, What are a quarter wave plates? Get the expre...

What are a quarter wave plates? Get the expressions for its thickness in terms of refractive indices for E-ray, O-ray and wavelength?

The effects of back emf on circuit current, The effects of back emf on circ...

The effects of back emf on circuit current: In proving the time constant, it was stated that, at the instant the switch is closed, the current (I) is zero.  This is because, at

Absolute and relative permeability of a medium, Distinguish between absolut...

Distinguish between absolute permeability and relative permeability of a medium Absolute Permeability: 1. Absolute permeability is the ability of the medium to allow th

Explain the lenz law, Explain the Lenz Law An induced current always fl...

Explain the Lenz Law An induced current always flows in a direction so that its electromagnetic field opposes the change in magnetic flux producing it. This is embodied in the

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