Charge transfer in an electrostatic generator operating in nitrobenzene

It has been proposed that the output current of an electrostatic generator might be increased by using a polar liquid as the insulating medium. The paper describes preliminary experiments carried out with a multipole generator whose rotor consisted of a glass disc of 20cm diameter. Nitrobenzene (¿r=36.7) was purified in a closed-circuit system until its resistivity was greater than 106¿m, and was then used in the generator. It was found that a positive or negative charge could be injected at the excitation terminals of the machine. The charge-collection efficiency at the output terminals was of the order of 70¿80%. A composite electrode is described which suppressed unwanted charge injection at the inductor electrodes. Short-circuit currents were measured as a function of the speed and excitation voltage. Results, both for singlepole and multipole conditions, were in fair agreement with the simple theory for this type of generator. Some suggestions for further work are given.