I used the very document that CrazyEwok is refering to (though at a different address) to make my high voltage and low voltage power supplies so if anyone wants to see the end result that you get from following the instructions in the document, the resulting High Voltage Inverter is at:
 http://rimstar.org/equip/30kv_pwr_supply.htm
and the resulting Low Voltage Power Supply (lower down in the document) is at:
 http://rimstar.org/equip/24v_pwr_supply.htm

The low voltage power supply gets its power from the grid and the high voltage one gets its power from the low voltage one. I use a 3amp variac between the grid and the low voltage power supply and that allows me to have the output of the low voltage one to range from 0-24V and the high voltage one from 1.2kV to 4.6kV (using the FOCUS wire on the multiplier) and from 4kV to 30kV (using the HV wire on the multiplier.)

The fuse on the low voltage power supply is only 1amp but that hasn't limited me yet. I've used them for years with all kinds of arcing and sparking and they've held up perfectly (keep 1amp fuses handy.) I've even used the low voltage one countless times for low voltage things. Just yesterday I wasn't sure if the 6volts worth of batteries in my photo tachometer were running low so I connected it to my low voltage power supply instead. This is a great combination of tools for a little effort in construction.
-Steve
http://rimstar.org   http://wsminfo.org

Sorry i should of been a little more specific. By resistance i mean mechanical resistance. i would of thought that there would of been none to very little resistance from the Van Der Graff but as i read about them i am hearing things about the wheel beeing harder to turn (don't know if this was the author getting tired or actual mechanical resistance)

i fail to see how a belt on 2 rollers could generat a large amount of resistance. Admittedly if the charge difference between the roller and the belt got high enough sure there would be some serious attraction but the whole point of the machine is that it strips the extra charge out of the belt...