Installation
3-16
Part 1618871−01
2020 Nordson Corporation
Spray Gun Current Path
See Figure 3-8. All electrical circuits need a complete path for current to
make its way back to the source. Electrostatic spray guns emit current
(ions) and therefore require a complete circuit. Some of the current emitted
by the spray gun is attracted to the spray booth, but most is attracted to the
grounded parts moving through the booth. The current attracted to the
parts flows through the part hangers to the conveyor and to the building
ground, back to the controller through a ground braid and back to the spray
gun through the spray gun driver board. The current attracted to the booth
is returned through the booth ground to the controller and back to the spray
gun.
It is very important to provide a complete circuit for the spray gun current. A
break in the circuit conductors (conveyor, booth, braided ground cables,
controller) can cause voltage to build up on the conductors up to the
maximum output of the spray gun voltage multiplier (up to 100 kV). The
voltage will eventually discharge in a high frequency arc, which can cause
damage to the controller electronics (spray gun driver board and power
supply).
Spray Gun Current Path
Ground Braid
Ions
Engage
Figure 3-8 Electrostatic Current Path
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