saps - 27-6-2005 at 16:14
Can I get my Van der graff generator to produce a negative electric field by changing the composition of its rollers???
Oxydro - 27-6-2005 at 16:33
Yes, you can, but I would suggest you look at a different source, since we deal more with chemistry here. Maybe http://forum.4hv.org/ would be good.
Also, try looking on: http://amasci.com/emotor/statelec.html -- he has a lot on such things.
PS -- maybe not just the rollers but the belt also will have to be changed.
saps - 27-6-2005 at 16:34
thank you
neutrino - 27-6-2005 at 18:06
Why would the belt have to be changed? IIRC, the only thing you need to change was the composition of the rollers and the electrical connections.
Oxydro - 27-6-2005 at 18:23
Um, I'm currently (no pun...) not up to speed on static and such, but the idea was that it is the difference in the triboelectric (?) potentials
between the two touching surfaces. So the belt will be either one that ends up negative, and the roller the opposite, or vice versa. The greater the
difference the better, so a belt set up for positively charging the terminal will not be efficient for charging it negatively.
Ah, on another look... it depends. Normally a neutral (steel, etc) upper roller is used, so it would be just the difference between the belt and the
roller that generate charge. Think of it like a battery - a magnesium/zinc cell won't generate much compared to a zinc/copper cell, for instance.
But in other cases, an active upper roller (opposite to the bottom one) is used and in that case, I don't think the belt really matters. If there
is less triboelectric potential difference between the belt and the roller at the bottom, there will simply be more at the top, and vice versa.
saps - 28-6-2005 at 08:28
What msterials would be best for making the ultimate charge negative?
Marvin - 28-6-2005 at 12:08
Remove the friction system (probably just a metal bar against the belt). Spray negative charge onto the base of the belt with a good home ioniser or
the charging system/corona wire from an old photocopier.
Van De Graff
saps - 22-7-2005 at 19:26
Does Robert Van De Graff's generator still have a valid patent or could companies utilize his technology like they do with that of generic
drugs??
Please stop posting new threads all the time! It's the 2nd I merged today!
[Edited on 23-7-2005 by chemoleo]
saps - 22-7-2005 at 20:00
but could i just change the rollers and/or belt and not use the corona wire? I was just thinking that maybe swithching the material's position on
the triboelectric series would do the job.
Cyrus - 22-7-2005 at 20:32
I've been "in the process" of building a vandegraaff generator for the last few years... anyhow I think teflon and nylon rollers are
plenty far apart on the triboelectric series, so I got solid teflon and nylon rollers machined for me. (from ebay, ouch that was expensive, but
someone machined them for free.)
saps - 22-7-2005 at 20:37
and the combination would create a negative charge on the sphere?
saps - 23-7-2005 at 07:28
all VDGs have a negative and a positive terminal, right?
neutrino - 23-7-2005 at 08:02
yes
saps - 23-7-2005 at 10:51
And both terminals emit the same amount of charge??
neutrino - 23-7-2005 at 12:58
By the law of conservation of charge, yes. If one terminal looses a certain number of electrons, the other has to gain that same number.
saps - 24-7-2005 at 07:21
Could i use the van der graff's charge to pick up dust and other objects??
moose sniffer - 24-7-2005 at 10:33
I believe that you would have to make sure that all of the objects you were picking up had an oposite charge. But how to do that? I dont know
moose sniffer - 24-7-2005 at 10:35
you might be able to use an ionizer
E.b.Chemoleo: Please edit your post next time rather than doubleposting...
[Edited on 24-7-2005 by chemoleo]
Ionizers
saps - 24-7-2005 at 11:02
could i use an ionizer to negatively or positevly charge dust?