Hi all,
I was investigating the possibility to use an inverter from rectified single
phase
220V main (about 300V DC) to 3 phase 110V 400 Hz for an HF linear
(max. 4 KW input) that was used on an aircraft.
The problem is not so simple.
I found that some converters and uninterruptible power supply have a square
wave output. While this will not be important for a computer or monitor
(the computer/monitor power input is directly rectified), it will be of great
importance when powering other equipment type.
Someone had a great surprise when a lighting bulb exploded and the soldering
iron had overheated when connected to that supply.
This can happen also with all directly connected R consumers, as the effective
voltage value is equal to the peak of the square output (in my case the tubes
filaments could be burned).
Some newer generation uninterruptible PS have also square output but at
reduced duty factor (just verified one with the scope).
I saw also an inverter diagram, and the output wave on the wave drawing was
square.
Please note that some inverters and converters used in the industry are designed
for powering high inductance loads, and in this case, the square output come
close to sinusoid (the output is for current, as I remember).
Others are using inductances for obtaining the same effect.
I saw the specs for an another newer type of PS and was specified the sinusoidal
output wave. I hadn't the possibility for verify on the scope yet.
73,
Traian
Peter Chadwick wrote:
> Bill asked:
>
> >Recall the discussion of running a 3 phase power supply
> >off of single phase mains?
>
> The model engineering people running 3 phase motors use either
> capacitive splits (so not true 3 phase) or inverters, or (a very few), motor
> generators.
>
> My inverter (for the mill and the lathe) can be bought for about $250 over
> here,
> and
> will provide variable frequency drive (thus variable speed) for a 1hp machine
> -
> it's
> about 850 watts continuous output. It's in a box about 6 inches by 5 inches by
> 3 inches. Output powers up to abt 3kW are available from large units.
>
> 73
>
> Peter G3RZP
>
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