Re: DC to AC Converter

To: tesla-at-pupman-dot-com
Subject: Re: DC to AC Converter
From: "Jim Lux" <jimlux-at-earthlink-dot-net> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Thu, 25 Mar 1999 20:46:44 -0700
Approved: twf-at-verinet-dot-com



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> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: DC to AC Converter
> Date: Wednesday, March 24, 1999 8:17 PM
> 
> Original Poster: gweaver <gweaver-at-earthlink-dot-net> 
> 
> I would like to have a converter to run my small portable TC from a car
> battery. Does anyone have a good circuit drawing for a converter that is
> small, simple, light weight, that really works. I need 750 watts, 120 VAC
> from 12 VDC 60 Hz.
> 
> I got a circuit from the web that uses two 2N3055 transistors that claims
to
> produce 250 watts output, but maximum output is really 60 watts and I
need a
> 1 lb. heat sink on each transistor.  I built a circuit using 10
transistors,
> 10 pounds of aluminum heat sinks, 500 watt transformer, and misc parts.
It
> produces 360 watts output, measures 12" by 12" by 16" and weights about
35 lbs.
> 
> Wal Mart has a 250 watt unit for $65.00 that weights about 2 lbs. 
> 
> I have some SCR's rated 400 amps 600 volts.  Is there a way to use an SCR
to
> build a converter? 
> 
> Gary Weaver
> 

Much better to buy the unit than build it, particularly if you get over a
few hundred watts. However, why bother going to 120VAC, why not build a HV
inverter that goes right from 12V to 15 kV. Presumably, you don't care
about frequency and how sinusoidal the waveform is? This would be much
easier, and would save the losses in the chain of inverter and hv
transformer. 

My Xray power supply uses two big SCR's in a 500 Hz inverter to do
essentially this: 100 V battery power to 100kV. The design is a bit tricky
though, and depends on the magnetic properties of the transformer, etc.