34 3. Countermeasures against Static Electricity
Prevents static electricity from being generated. q Proper selection of materials that come into contact with each other (Utilizing the triboelectric series) w Reduction of the contact area Generation of static electricity increases as the contact area increases. Equipment designs with less contact area are required. e Reduction in the frequency with which objects come into contact with each other Static electricity accumulates when objects come into contact with each other repeatedly. Reduce the frequency with which objects come into contact with each other to reduce the generation of static electricity. r Control of capacitance Static electricity voltage fluctuates with capacitance. Capacitance needs to be controlled to prevent static electricity from increasing unnecessarily. S d Static electricity voltage and capacitance
Static electricity voltage Static electricity voltage can be calculated using the formula below. Voltage (V) = Quantity of Electric Charge (Q) / Capacitance (C) When the quantity of electric charge is constant, the voltage fluctuates with capacitance. Example: When capacitance decreases, voltage increases.
Capacitance (C) The capacity to store static electricity between two objects. The capacitance between flat plates increases in proportion to the area (S) and decreases when the distance (d) between the flat plates becomes larger. Example: The static electricity voltage of a workpiece on the table increases when the workpiece is lifted with a lifter because the capacitance becomes smaller.