How did Tesla create such high frequency currents?

[Strangeline]

I've read his book and he talks about AC current frequencies of incredibly high magnitudes. How was this achieved? Surely he did not just spin his dynamo really, really fast.

 

[Drakkith]

How high did he go? Does your book say?

 

[CWatters]

Perhaps..

http://www.mentallandscape.com/Tesla1.htm

His first experiments were with a unique new high frequency alternator [5]. This was made up of a steel disk 30 inches in diameter with 384 poles like the teeth of a cog that had zigzag windings on them. This disk revolved within a fixed ring that had 384 inductor poles. When this machine was turned at 3000 rpm, it produced about 200 volts at 9600 to 10,000 Hz. Tesla was the first man to work with such a device [6]. Later machines of somewhat different design produced up to 30,000 Hz.

It continues with a description of his later work including a spark gap LC transmitter. Basically this is a resonant circuit that is hit with an impulse to make it "ring" at the resonant frequency.

 

[Dickfore]

10 kHz is still in the acoustic domain (for sound). Why is this "such high frequency" according to you? When you say something is very large, or very small, you must tell us what physical quantity of the same kind you are comparing it with.