P7. What is the function of the corrugations on the insulator?

The grooves guarantee isolation and avoid electric discharge.

 
 

 

During the spark emission:

A high voltage is applied to the area between the ending screw-nut and the metal cover.

 

The high voltage tends to leak along the isolator surface.

Electric Discharge


There won't be any sparks and there will be an ignition failure.

 

To prevent this from happening:

Grooves are incorporated as isolator parts.

These grooves widen the isolation distance and guarantee the isolation.

They mantain normal sparks

 

Resistance voltage to electric discharges

Resistance voltage to electric discharges (KV)
15
20
25
30
35
With five grooves
 
Without grooves