Here's another way, found on ebay. Looks to be maybe 20yrs old now. (geez, that's NOT so far back as to be called "old" is it??)
http://www.ebay.com/itm/High-Voltage-Capacitor-Charging-Power-Supply-1-7-kv-1-kw-/301422095495?pt=LH_DefaultDomain_0&hash=item462e282c87takes 3ph input...
"Input power goes through a 15 amp breaker to a 3 phase full wave rectifier. This DC power feeds two SCRs in push-pull that drive a transformer. The SCRs are fired by a circuit that accepts an external low voltage signal to control the output voltage. The transformer has 4 identical isolated secondary windings that go to individual full wave bridge rectifiers. The rectifier outputs are wired in series to provide the module’s actual output voltage. There are also 2 opto-isolated low voltage inputs that appear to be for interlock/enable functions. The red pilot light on the front panel may be for fault indication."
Control circuitry is on the bottom, FYI. Not shown in the image.
