3-phase from DC converter?

[Joe in Bendigo]

I require a 3-phase power source of 115VAC @ 400Hz with an output of around
100mA or so. I would like to power this from 12-14V DC.
Does anyone have any suggestions about a circuit I could use - or design one
for me?
The connections to the device I want to run (an ancient attitude gauge or
artificial horizon from a vintage aircraft) is delta configuration
(delta-wound gyro motors) - no centre or common connector.
Cheers,
Joe

 

[Joerg]

Hi Joe,

You could contact some stores that cater to land surveyors. There are
some three-phase 115V 400Hz gyros used in that field, or at least they
used to. Since they often work off grid using a 12V battery there should
be inverters offered. I have seen one a long time ago and since these
gyros use so much power the inverter is kind of large, it was the size
of a brick.

Regards, Joerg

http://www.analogconsultants.com

 

[Joe in Bendigo]

Will try that lead Joerg. Thank you.
Although that sounds like it might be expensive....
Cheers,
Joe

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:_CZCc.1216$XX1.814@newssvr27.news.prodigy.com...

Hi Joe,

You could contact some stores that cater to land surveyors. There are
some three-phase 115V 400Hz gyros used in that field, or at least they
used to. Since they often work off grid using a 12V battery there should
be inverters offered. I have seen one a long time ago and since these
gyros use so much power the inverter is kind of large, it was the size
of a brick.

Regards, Joerg

http://www.analogconsultants.com

 

[Phil Allison]

"Joe in Bendigo"

I require a 3-phase power source of 115VAC @ 400Hz with an output of
around
100mA or so. I would like to power this from 12-14V DC.
Does anyone have any suggestions about a circuit I could use - or design
one
for me?

** A switch mode, 400 Hz three phase inverter for use with avionics was
published in "Electronics World " in the February 1999 issue, p127.

But it ain' t simple.




............ Phil

 

[Paul Mathews]

"Joe in Bendigo" <jhovel@-spam-gmx.net> wrote in message news:<cGVCc.63981$sj4.14558@news-server.bigpond.net.au>...

I require a 3-phase power source of 115VAC @ 400Hz with an output of around
100mA or so. I would like to power this from 12-14V DC.
Does anyone have any suggestions about a circuit I could use - or design one
for me?
The connections to the device I want to run (an ancient attitude gauge or
artificial horizon from a vintage aircraft) is delta configuration
(delta-wound gyro motors) - no centre or common connector.
Cheers,
Joe

Low tech but possibly heavy and inefficient solution: generate three
400Hz signals locked in relative phase to drive 3 'car audio' power
amplifiers (could be switchmode). These power amps drive 3
transformers. The transformers could be 120V/12V types, with the amps
driving the 12V side. Transformer VA rating could be considerably
less than the wattage of your load, since power ratings would be
effectively higher at 400Hz (compared to their 50 or 60Hz VA rating
frequency).

Paul Mathews

 

[Joerg]

Hi Joe,

Will try that lead Joerg. Thank you.
Although that sounds like it might be expensive....


Yes, it could be expensive. But you might also try surplus dealers that

sell discarded mil and industrial gear. With some luck one of them sits
on a stash of those and is eager to let them go. That's where I used to
get the best deals.

Regards, Joerg

http://www.analogconsultants.com

 

[Phil Allison]

"Paul Mathews"

Transformer VA rating could be considerably
less than the wattage of your load, since power ratings would be
effectively higher at 400Hz (compared to their 50 or 60Hz VA rating
frequency).

** The VA rating at 400 Hz will be virtually the same as at 50/60 Hz. The
magnetising current in the primary will reduce at the higher operating
frequency but since this is a small fraction of the rated current ( indeed
small for a toroidal) there is not much overall change.




.............. Phil

 

[N. Thornton]

"Phil Allison" <philallison@tpg.com.au> wrote in message news:<2k6jfgF18mkeaU1@uni-berlin.de>...

"Paul Mathews"

Transformer VA rating could be considerably
less than the wattage of your load, since power ratings would be
effectively higher at 400Hz (compared to their 50 or 60Hz VA rating
frequency).



** The VA rating at 400 Hz will be virtually the same as at 50/60 Hz. The
magnetising current in the primary will reduce at the higher operating
frequency but since this is a small fraction of the rated current ( indeed
small for a toroidal) there is not much overall change.

Youd have to rewind it with less turns of thicker wire to see a power
handling increase.

Regards, NT

 

[Larry]

bigcat@meeow.co.uk (N. Thornton) wrote in message news:<a7076635.0407041344.443ad8c1@posting.google.com>...

"Phil Allison" <philallison@tpg.com.au> wrote in message news:<2k6jfgF18mkeaU1@uni-berlin.de>...
"Paul Mathews"

Transformer VA rating could be considerably
less than the wattage of your load, since power ratings would be
effectively higher at 400Hz (compared to their 50 or 60Hz VA rating
frequency).



** The VA rating at 400 Hz will be virtually the same as at 50/60 Hz. The
magnetising current in the primary will reduce at the higher operating
frequency but since this is a small fraction of the rated current ( indeed
small for a toroidal) there is not much overall change.

Youd have to rewind it with less turns of thicker wire to see a power
handling increase.

Regards, NT

Did you look into the surplus market for a MG unit from places like.
> C & H sales in Cal. Hope it helps