RE: 48kW DRSSTC

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

> the only thing that has
> me stumped is how I
> am going to control a 200 amp voltage double without
> a heavy transformer/variac.

*ahem* SCRs :-)

I used SCR controlled rectifiers in my OLTC2 and in my
new DRSSTC. The DC link voltage can be varied from
zero to 100% without a variac.

This approach isn't ideal: the controlled rectifier
has lousy power factor at less than 100% output
voltage. Adding inductance in the line improves things
but at the cost of voltage droop under load, and extra
size and weight.

But it's fairly easy to build and get working- it's
just a giant lamp dimmer after all- and SCRs are
almost indestructible. They (along with diodes) are
the only semiconductors you can actually protect with
fuses. Also, at full output voltage, the power factor
is no worse than an ordinary diode rectifier.

This is my original 4kW voltage doubler with 240V, 30A
in and variable 0-600V DC out. Note that us "Limeys"
call SCRs "thyristors".

http://www.scopeboy.com/tesla/ol2psu.html

Steve Conner
http://www.scopeboy.com/