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

Length contraction is invisible, Length Contraction is Invisible This s...

Length Contraction is Invisible This series of animations describes that the relativistic length contraction is invisible.

Why does heated air expand, Why does heated air expand? Temperature is ...

Why does heated air expand? Temperature is often explained as the average thermal energy of the substance at hand. Therefore the hotter a substance is the more thermal energy i

How greatly does automotive oil weigh, Q. How greatly does automotive oil w...

Q. How greatly does automotive oil weigh? Answer:- As a rough guide engine oil typically weighs about 0.87 kg/litter or about 7.2 pounds per US gallon. Regrettably a rough

Explain logic gates, The digital circuit that can be examined with the help...

The digital circuit that can be examined with the help of Boolean algebra is known as logic circuit or logic gate. A logic circuit has two or more inputs but only one output. Th

Lami''s theorem and sine rule, a uniform sphere of mass 2kg is kept in a fi...

a uniform sphere of mass 2kg is kept in a fixed position by two strings AB and CD. AB is horizontal and CD is inclined at 30° to the vertical. calculate the tension in each string.

Coulomb force experienced at its centre, a) Three equivalent charges 2.0 mi...

a) Three equivalent charges 2.0 micro coulomb each, are held fixed at the three corners of an equilateral triangle of side 5 cm. Determine the Coulomb force experienced at its cent

Does sunlight reflected off a mirror raise, Q. Does sunlight reflected off ...

Q. Does sunlight reflected off a mirror raise the temperature of the sun-rays? Answer:- A standard planar mirror will not raise the energy contained in the rays that refle

Define conduction, Figure denotes a rod whose ends are in thermal contact w...

Figure denotes a rod whose ends are in thermal contact with a hot reservoir at temperature T1 and a cold reservoir at temperature T2.  The ends of the rod are covered with insulati

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