| Author | Message | ||
     DanielFrengel |
howdy, i just finished building the vandegraff generator, and everything spins and stays where its supposed to, but theres no static electricity in the can. Ive checked the brushes, played with the pulley (taken it off ) and i have no idea whats wrong. any help? | ||
| Simon Quellen Field (Sfield) |
Try a different brand of rubber band. Some are slightly conductive, and won't work. Grease and dirt are also slightly conductive, and so everything should be clean. Use a good ground such as a cold water pipe for the wire coming from the bottom can. Make sure the brushes don't touch the rubber band. | ||
| danielfrengel |
thanks alot, i havent tried it yet (in college for the summer, doing more thana full time load) when i can pull it together i'll make another go at it for the weekend and let ya know how it goes. I also think part of the problem was one of the parts, it didnt look like it was made from the same PVC stuff so i bought another one that looks alot better. anywho, no more substitutions and i'll try your advice. ALSO, i live in alabama, you think the humidity might have a role in this? | ||
| Simon Quellen Field (Sfield) |
Humidity will definitely have an effect. Try it in an air-conditioned building. | ||
| DanielFrengel |
i replaced the part, tried different rubber bands and connected it to a good ground. Nothing happened. does glueing the styrofoam cup in place have an effect on the electricity or is it just to hold it in place? I have no idea why it wont work. Also, i did it in an air conditioned building, but its still pretty humid everywhere you go in alabama in the summer time. | ||
| Simon Quellen Field (Sfield) |
Let's ask the group. Does anyone have experience doing static electricity experiments in humid places? | ||
| DanielFrengel |
Howdy Mr. Field. Its me again, to thank you for the help you gave me i wanted to give you this link. i would have put it on the ideas for new toys but i didnt know if youd see it or not so i decided to do it here. http://www.discoverchemistry.com/dcv2-docroot/student/fun_stuff/electric_pickle/ it looked like a fun idea. Also, another design for a more advanced Generator is at http://www.fortunecity.com/greenfield/bp/16/vandegra.htm#Entire%20Parts%20List%20:. If i am absebt mindedly unsulting yoru intellegence with these links i apologize  | ||
| Anonymous |
where is the link for the van de graff generator I can't find it on the homepage. | ||
| Simon Quellen Field (sfield) Senior Member Username: sfield Post Number: 270 Registered: 12-2004 |
Try Fun with High Voltage. | ||
| Kevin H Unregistered guest |
Will the generator (mini PVC one) make a constant spark like a tesla coil if a grounded object is very close or will it just spark intermittantly? Is there any way to make constant sparks of lightning/static??? | ||
| Simon Quellen Field (sfield) Senior Member Username: sfield Post Number: 385 Registered: 12-2004 |
The VDG will generate sparks whose recovery time is dependent on the capacitance of the top surface and the voltage of the spark. To increase the repetition rate, make the spark shorter or the can smaller. Either one will make the spark less impressive. If you want an arc, go with the Tesla coil. | ||
| Anonymous |
To reduce the effects of humidity, you can replace the belt of a Van de Graff generator with sealed pipe of dry air. The motor at the bottom can be replaced with an air pump but instead of pumping air your circulating it through the pipe. The pipe will leave the air pump; going up into the metal dome (still enclosed in pipe,) then comes down and goes back into the air pump. This circle makes 2 columns of pipe in the shaft of the generator (assume the left column is leaving the air pump, and the right column is the entering the air pump). The pipe should be non-conductive in all areas except where it enters and exits the metal dome at the top. In the middle of the shaft where the 2 columns of pipe are, each column should have electrodes inserted into them. The electrodes should be placed so that when a DC source is connected to them, it generates an arc inside the column. Both columns should have it's own electrodes that have reversed voltage polarity (ie if the left hand column's electrodes are powered with a DC source that’s + -, the right hand should be the same magnitude but - +.) What this does is allow isolated air to be ionized as it flows up to the dome via the spark gap. The ionized air delivers its charge to the metal dome as it enters and exits at the top. As it flows down, it meets the second arc of reversed poles and de-ionizes any molecule that might have not transferred charge to the dome. The air pump re-circulates this air and the process happens again -- much like the belt. The difference is that the air never wears out and delivers charge much more rapidly than a belt ever could. Also, because the pipes are sealed, the effects of humidity on the system are greatly diminished. A warning though, this takes a lot of time to complete and requires some background on electricity (mainly in setting up the spark gaps and their voltage levels.) | ||
| Josh (Unregistered Guest) Unregistered guest Posted From: 72.235.129.42 |
What would be the humidity % ? Where I live it never goes below 70%. Thanks | ||
| mike (Mike11298) Junior Member Username: Mike11298 Post Number: 7 Registered: 10-2006 |
under 40% is best, if it is 96%, you need to use an air conditioned room. TIP: You know those little silica gel things you find in everything? place one or two at the bottom of your generator to aid in drying the column. Moisture in the column can be dried with a hair drier. |
