VOLTAGE difference

[moonflower]

I am trying to understand what the effects of a voltage difference would have in the method of electrostatic charge spray painting..

 

[swansont]

What happens to the charged droplets of paint if there is a potential difference vs no difference (or a difference of the wrong sign)?

 

Bonus: What happens to the droplets, with respect to each other, because they are charged?

[moonflower]

If the droplets of paint are charged positive and the object to be charged negative then the positive droplets will be attracted to the object to be painted.

 

if the object to be painted was also charged positive then the spray paint would not be very efficient and i would imagine cause a big mess.

 

Correct?

 

I think im just a bit lost (again) in respects to the definition of voltage difference and what it actually does in this process...

[swansont]

The potential difference (Voltage) tells you the energy per unit charge that you will add to a particle as it moves from one point to another. So you will be adding kinetic energy to the charged droplets; they will feel a force toward the target due to the presence of an electric field. Which means in this case that the paint won't tend to spread out and miss the thing you're painting. (Unless you have it backwards, as you suspected, and then the charges will repel and it won't be very effective at all.)

 

Also, because you've charged the droplets, they'll repel each other and not tend to clump into larger drops, which doesn't look as good.

[moonflower]

so if my question reads, explain how the process works and why a voltage difference must be applied to the system of the nozzle and article during the painting process..

 

A voltage difference would need to be applied to charge each droplet of paint to pick up a positive charge (they do this by loosing negative electrons). The article to be painted is given a high voltage negative charge which will then attract the positively charged droplets.... ???????

 

Is my answer correct? x (thanks so much)

[swansont]

That's the right concept. "high voltage negative charge" isn't really the right way to word it, though. It's a "large negative potential" (assuming the source is at ground, which would be the safest way to do it)

[moonflower]

Brill thanks. xxx