Why should we worry about static electricity? - Electrostatic ...

Different types of ESD have
different ability to ignite materials
ESD type
Spark
Propagating
brush
Brush
Cone
Corona
Where it occurs
Between two conductors
From insulator backed
by a conductor
From insulators
Highly charged insulating
powder cones in silos
Sharp edges on charged
conductors
Will ignite
Gas mixtures and
dusts
Gas mixtures and
dusts
Gas mixtures
Gas mixtures and
low MIE dusts
Not usually
incendive
© Electrostatic Solutions Ltd 2 February 2006
www.electrostatics.net 10
Understanding static
electricity
© Electrostatic Solutions Ltd 2 February 2006
www.electrostatics.net
Where does electrostatic charge
come from
• Every material is made up of charge
– Negative electrons
– Positive atomic nuclei
• These charges are normally present in
balance, and their effects cancel
– If there is a local imbalance we may see
static electricity effects
• charge transferred between materials
in contact
– electrons flow from one material to the
other
• materials separate and take equal and
opposite polarity (positive and
negative) charge
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© Electrostatic Solutions Ltd 2 February 2006
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