Inverter question for Jim Weir

[B2431]

Could you figure a way to convert the automobile inverters for laptops to 400z?
How about the LCD inverters?

Dan, U.S. Air Force, retired

[[email protected]]

I would take this to mean the other way.... modifying an automotive inverter to
put out 400Hz output. I'm guessing this would be to power some funky avionics requiring
400Hz from a 14V plane. If it's a PWM output, it probably wouldn't even be all that hard
to do, since it's still 120v. I don't think it'd be a good idea for a plane though.
Consumer-grade stuff doesn't quite have the robustness and interference requirements to
make it adequate on a plane.

-Cory

karel adams > wrote:

: "B2431" > schreef in bericht
: ...
:> Could you figure a way to convert the automobile inverters for laptops
: to 400z?

: if I understand your question allright,
: you are wondering how a commercial automobile converter
: can be used to power a laptop off the 400hz 3phase
: electrical power available in larger planes?

: well i suppose you first rectify the 400 Hz into DC
: using diodes that will withstand the currents involved
: (between 5 and 10 amps maximum, I should reckon)
: then you reduce whatever DC voltage results to some 12-15 volts
: then you feed this into the car inverter
: don't forget to include some inductances (=chokes)
: and ceramic C's to reduce HF-disturbance

: KA



--
************************************************** ***********************
* The prime directive of Linux: *
* - learn what you don't know, *
* - teach what you do. *
* (Just my 20 USm$) *
************************************************** ***********************

[Jay]

I'm trying to understand what you want to do. You want 400Hz power in
your DC plane? What is it you trying to power?

(B2431) wrote in message >...
> Could you figure a way to convert the automobile inverters for laptops to 400z?
> How about the LCD inverters?
>
> Dan, U.S. Air Force, retired

[Jim Weir]

I love it when people without a clue jump on your questions that you asked me.

It can be done. I'm not sure how trivial the mod would be, but if you are
talking about powering 115v/400Hz. gyros, as I recall you will need three phase.

So the answer to question one is yes, I can probably figure out a way. I'm not
sure how detailed the answer will be, or whether the answer will travel from one
model to another or be specific to that model.

Now, what is an LCD inverter?

Jim


(B2431)
shared these priceless pearls of wisdom:

->Could you figure a way to convert the automobile inverters for laptops to
400z?
->How about the LCD inverters?
->
->Dan, U.S. Air Force, retired

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Tarver Engineering]

"Jim Weir" > wrote in message
...
> I love it when people without a clue jump on your questions that you asked
me.
>
> It can be done. I'm not sure how trivial the mod would be, but if you are
> talking about powering 115v/400Hz. gyros, as I recall you will need three
phase.

No.

[richard riley]

On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:

:I love it when people without a clue jump on your questions that you asked me.
:
:It can be done. I'm not sure how trivial the mod would be, but if you are
:talking about powering 115v/400Hz. gyros, as I recall you will need three phase.

Most of the 115v/400 hz gyros out there are 3 phase, but not all. I
have one that isn't - it's not working and it's not worth rebuilding.
I'd guess 90% or more are three phase.

I've also just found a guy in England that makes 12v to
115v/400hz/3phase inverters, 1.5 lbs, with a .5 amp 24v DC output as
well. Not cheap at 225 uk pounds. Chris Quayle,
lightwork(at)aerosys(dot)co(dot)uk

[Tarver Engineering]

"richard riley" > wrote in message
...
> On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:
>
> :I love it when people without a clue jump on your questions that you
asked me.
> :
> :It can be done. I'm not sure how trivial the mod would be, but if you
are
> :talking about powering 115v/400Hz. gyros, as I recall you will need three
phase.
>
> Most of the 115v/400 hz gyros out there are 3 phase, but not all. I
> have one that isn't - it's not working and it's not worth rebuilding.
> I'd guess 90% or more are three phase.

Most airplane instrumentation is devided by phase, gyros being one of the
most critical pieces of instrumentation for IFR operations.

Mechanical INS are three phase, but they have battery back up.

[clare @ snyder.on .ca]

On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:

>I love it when people without a clue jump on your questions that you asked me.
>
>It can be done. I'm not sure how trivial the mod would be, but if you are
>talking about powering 115v/400Hz. gyros, as I recall you will need three phase.
>
>So the answer to question one is yes, I can probably figure out a way. I'm not
>sure how detailed the answer will be, or whether the answer will travel from one
>model to another or be specific to that model.
>
>Now, what is an LCD inverter?
>
>Jim
>
>
(B2431)
>shared these priceless pearls of wisdom:
>
>->Could you figure a way to convert the automobile inverters for laptops to
>400z?
>->How about the LCD inverters?
>->
>->Dan, U.S. Air Force, retired
>
>Jim Weir (A&P/IA, CFI, & other good alphabet soup)
>VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
>http://www.rst-engr.com


I think by LCD inverter he's talking about the "exciter" for the CCF
backlights used on LCD laptop screens. Aprox 400cps, but far from
accurate, and very low current.

[Tim Ward]

"Tarver Engineering" > wrote in message
...
>
> "richard riley" > wrote in message
> ...
> > On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:
> >
> > :I love it when people without a clue jump on your questions that you
> asked me.
> > :
> > :It can be done. I'm not sure how trivial the mod would be, but if you
> are
> > :talking about powering 115v/400Hz. gyros, as I recall you will need
three
> phase.
> >
> > Most of the 115v/400 hz gyros out there are 3 phase, but not all. I
> > have one that isn't - it's not working and it's not worth rebuilding.
> > I'd guess 90% or more are three phase.
>
> Most airplane instrumentation is devided by phase, gyros being one of the
> most critical pieces of instrumentation for IFR operations.
>
> Mechanical INS are three phase, but they have battery back up.

Cool! Where do they get those 3-phase batteries?

Tim Ward

[Tarver Engineering]

"Tim Ward" > wrote in message
...
>
> "Tarver Engineering" > wrote in message
> ...
> >
> > "richard riley" > wrote in message
> > ...
> > > On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:
> > >
> > > :I love it when people without a clue jump on your questions that you
> > asked me.
> > > :
> > > :It can be done. I'm not sure how trivial the mod would be, but if
you
> > are
> > > :talking about powering 115v/400Hz. gyros, as I recall you will need
> three
> > phase.
> > >
> > > Most of the 115v/400 hz gyros out there are 3 phase, but not all. I
> > > have one that isn't - it's not working and it's not worth rebuilding.
> > > I'd guess 90% or more are three phase.
> >
> > Most airplane instrumentation is devided by phase, gyros being one of
the
> > most critical pieces of instrumentation for IFR operations.
> >
> > Mechanical INS are three phase, but they have battery back up.
>
> Cool! Where do they get those 3-phase batteries?

Perhaps weir can provide you with a schematic for a three phase batter
charger.

[Jerry Wass]

clare, @, snyder.on, .ca wrote:

> On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:
>
> >I love it when people without a clue jump on your questions that you asked me.
> >
> >It can be done. I'm not sure how trivial the mod would be, but if you are
> >talking about powering 115v/400Hz. gyros, as I recall you will need three phase.
> >
> >So the answer to question one is yes, I can probably figure out a way. I'm not
> >sure how detailed the answer will be, or whether the answer will travel from one
> >model to another or be specific to that model.
> >
> >Now, what is an LCD inverter?
> >
> >Jim
> >
> >
> (B2431)
> >shared these priceless pearls of wisdom:
> >
> >->Could you figure a way to convert the automobile inverters for laptops to
> >400z?
> >->How about the LCD inverters?
> >->
> >->Dan, U.S. Air Force, retired
> >
> >Jim Weir (A&P/IA, CFI, & other good alphabet soup)
> >VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
> >http://www.rst-engr.com
>
> I think by LCD inverter he's talking about the "exciter" for the CCF
> backlights used on LCD laptop screens. Aprox 400cps, but far from
> accurate, and very low current.

However, I think the auto inverters for laptops are probably the 150-to 600+
watt 12 DC to 120 AC inverters that plug into the cig lighter socket & let you use
a laptop, shaver, whatever uses house current.
I made a HIGH POWERED strobe light that took about 450-500 vdc to pump
up the flash caps--Thought about winding toroid for transistor oscillator power
supply----But, then I let the Chinks do it--just used a 250 watt inverter and a
simple
voltage tripler circuit to power it... Jerry

[B2431]

>From: "Tim Ward"
>Date: 2/11/2004 9:58 PM Central Standard Time
>Message-id: >
>
>
>"Tarver Engineering" > wrote in message
...
>>
>> "richard riley" > wrote in message
>> ...
>> > On Wed, 11 Feb 2004 12:28:32 -0800, Jim Weir > wrote:
>> >
>> > :I love it when people without a clue jump on your questions that you
>> asked me.
>> > :
>> > :It can be done. I'm not sure how trivial the mod would be, but if you
>> are
>> > :talking about powering 115v/400Hz. gyros, as I recall you will need
>three
>> phase.
>> >
>> > Most of the 115v/400 hz gyros out there are 3 phase, but not all. I
>> > have one that isn't - it's not working and it's not worth rebuilding.
>> > I'd guess 90% or more are three phase.
>>
>> Most airplane instrumentation is devided by phase, gyros being one of the
>> most critical pieces of instrumentation for IFR operations.
>>
>> Mechanical INS are three phase, but they have battery back up.
>
>Cool! Where do they get those 3-phase batteries?
>
>Tim Ward
>
>
Beat me to it, ya bum. :)

Dan, U.S. Air Force, retired

[B2431]

>Jim Weir
>From: Jim Weir

>
>I love it when people without a clue jump on your questions that you asked
>me.
>
>It can be done. I'm not sure how trivial the mod would be, but if you are
>talking about powering 115v/400Hz. gyros, as I recall you will need three
>phase.

Someone gave me a neat trick using a cpacitor off one leg to trick the
instrument into thinking it's the third phase.

>So the answer to question one is yes, I can probably figure out a way. I'm
>not sure how detailed the answer will be, or whether the answer will travel
from
>one model to another or be specific to that model.

This is an example of the type of inverter I have in mind:
http://cgi.aol.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3459345456&category
=42167
>
>Now, what is an LCD inverter?

Example:
http://cgi.aol.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3457538717&category
=42187

>
>Jim
>
>
Dan, U.S. Air Force, retired

[clare @ snyder.on .ca]

On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward" >
wrote:

>

>> Mechanical INS are three phase, but they have battery back up.
>
>Cool! Where do they get those 3-phase batteries?
>
>Tim Ward
>
Same place they get the AC batteries, I suspect.

[Tarver Engineering]

<clare @ snyder.on .ca> wrote in message
...
> On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward" >
> wrote:

> >> Mechanical INS are three phase, but they have battery back up.
> >
> >Cool! Where do they get those 3-phase batteries?

> Same place they get the AC batteries, I suspect.

It has more to do with the DC accelerometers and designing for reliability.

Back when 707s ruled the world there were mag amps for operational
amplifiers and mica capacitors were what could survive comertial operations
and storage. A three phase DC source with a battery is how clean DC power
could be made reliably.

[frank]

Silly, they just use 3 little batteries instead of 1 big one.

[Tim Ward]

"Tarver Engineering" > wrote in message
...
>
> <clare @ snyder.on .ca> wrote in message
> ...
> > On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward" >
> > wrote:
>
> > >> Mechanical INS are three phase, but they have battery back up.
> > >
> > >Cool! Where do they get those 3-phase batteries?
>
> > Same place they get the AC batteries, I suspect.
>
> It has more to do with the DC accelerometers and designing for
reliability.
>
> Back when 707s ruled the world there were mag amps for operational
> amplifiers and mica capacitors were what could survive comertial
operations
> and storage. A three phase DC source with a battery is how clean DC power
> could be made reliably.

I know I'm going to hate myself for asking, but what is "three phase DC"?
How do you determine the phase angle of DC?

Tim Ward

[Tarver Engineering]

"Tim Ward" > wrote in message
...
>
> "Tarver Engineering" > wrote in message
> ...
> >
> > <clare @ snyder.on .ca> wrote in message
> > ...
> > > On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward" >
> > > wrote:
> >
> > > >> Mechanical INS are three phase, but they have battery back up.
> > > >
> > > >Cool! Where do they get those 3-phase batteries?
> >
> > > Same place they get the AC batteries, I suspect.
> >
> > It has more to do with the DC accelerometers and designing for
> reliability.
> >
> > Back when 707s ruled the world there were mag amps for operational
> > amplifiers and mica capacitors were what could survive comertial
> operations
> > and storage. A three phase DC source with a battery is how clean DC
power
> > could be made reliably.
>
> I know I'm going to hate myself for asking, but what is "three phase DC"?
> How do you determine the phase angle of DC?

Three phase is easy to convert to DC.

[B2431]

>From: "Tarver Engineering"
>
>
>"Tim Ward" > wrote in message

>>
>> "Tarver Engineering" > wrote in message
>> ...
>> >
>> > <clare @ snyder.on .ca> wrote in message
>> > ...
>> > > On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward" >
>> > > wrote:
>> >
>> > > >> Mechanical INS are three phase, but they have battery back up.
>> > > >
>> > > >Cool! Where do they get those 3-phase batteries?
>> >
>> > > Same place they get the AC batteries, I suspect.
>> >
>> > It has more to do with the DC accelerometers and designing for
>> reliability.
>> >
>> > Back when 707s ruled the world there were mag amps for operational
>> > amplifiers and mica capacitors were what could survive comertial
>> operations
>> > and storage. A three phase DC source with a battery is how clean DC
>power
>> > could be made reliably.
>>
>> I know I'm going to hate myself for asking, but what is "three phase DC"?
>> How do you determine the phase angle of DC?
>
>Three phase is easy to convert to DC.
>

Tim, you should know better than to ask. As you can see he twists his answer so
he won't have to admit he made a mistake when he said "a three phase DC
source."

Dan, U.S. Air Force, retired

[Tarver Engineering]

"B2431" > wrote in message
...
> >From: "Tarver Engineering"
> >
> >
> >"Tim Ward" > wrote in message
>
> >>
> >> "Tarver Engineering" > wrote in message
> >> ...
> >> >
> >> > <clare @ snyder.on .ca> wrote in message
> >> > ...
> >> > > On Wed, 11 Feb 2004 19:58:40 -0800, "Tim Ward"
>
> >> > > wrote:
> >> >
> >> > > >> Mechanical INS are three phase, but they have battery back up.
> >> > > >
> >> > > >Cool! Where do they get those 3-phase batteries?
> >> >
> >> > > Same place they get the AC batteries, I suspect.
> >> >
> >> > It has more to do with the DC accelerometers and designing for
> >> reliability.
> >> >
> >> > Back when 707s ruled the world there were mag amps for operational
> >> > amplifiers and mica capacitors were what could survive comertial
> >> operations
> >> > and storage. A three phase DC source with a battery is how clean DC
> >power
> >> > could be made reliably.
> >>
> >> I know I'm going to hate myself for asking, but what is "three phase
DC"?
> >> How do you determine the phase angle of DC?
> >
> >Three phase is easy to convert to DC.
> >
>
> Tim, you should know better than to ask. As you can see he twists his
answer so
> he won't have to admit he made a mistake when he said "a three phase DC
> source."

[Jim Weir]

Tim, I thought you had been around long enough to know this. Perhaps not.
There is a very special killfile called a Tarverfile. Put this idiot into it.

Jim


"Tim Ward" >
shared these priceless pearls of wisdom:

->I know I'm going to hate myself for asking, but what is "three phase DC"?
->How do you determine the phase angle of DC?



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[RU ok]

On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:

>Tim, I thought you had been around long enough to know this. Perhaps not.
>There is a very special killfile called a Tarverfile. Put this idiot into it.
>
>Jim
>
>
>"Tim Ward" >
>shared these priceless pearls of wisdom:
>
>->I know I'm going to hate myself for asking, but what is "three phase DC"?
>->How do you determine the phase angle of DC?
>
>
>
>Jim Weir
++++++++++++++++++++++++++++++++++++++++

You mean the alternator on my car isn't
three phase furnishing DC to charge the battery"?

FWIW...
Just because you know what somebody said,
doesn't mean you understand what they meant. <g>


Barnyard BOb - unofficial devil's advocate

[Tarver Engineering]

"Jim Weir" > wrote in message
...
> Tim, I thought you had been around long enough to know this. Perhaps not.
> There is a very special killfile called a Tarverfile. Put this idiot into
it.

Yes Tim, otherwise you won't be captive to Weir's massive ignorance.

[Tarver Engineering]

"RU ok" > wrote in message
...
> On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:

<snip of senile old fool>

> You mean the alternator on my car isn't
> three phase furnishing DC to charge the battery"?

Yes, it is.

[Big John]

Tarver

I beg to differ.

When you burn out a rectifier in your alternator (like I have on
numerous occasions) then you are only putting out Two Phase to your
battery and system.


Big John


On Fri, 13 Feb 2004 08:03:34 -0800, "Tarver Engineering"
> wrote:

>
>"RU ok" > wrote in message
...
>> On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:
>
><snip of senile old fool>
>
>> You mean the alternator on my car isn't
>> three phase furnishing DC to charge the battery"?
>
>Yes, it is.
>

[Tarver Engineering]

"Big John" > wrote in message
...
> Tarver
>
> I beg to differ.
>
> When you burn out a rectifier in your alternator (like I have on
> numerous occasions) then you are only putting out Two Phase to your
> battery and system.

The diodes are in the three phase alternator.

A two phase alternator would be an inherently unbalanced load.

[Big John]

Tarver

Yep.

So.<G>

Charged battery and ran load ok until I could get repaired.

Big John



On Fri, 13 Feb 2004 10:09:13 -0800, "Tarver Engineering"
> wrote:

>
>"Big John" > wrote in message
...
>> Tarver
>>
>> I beg to differ.
>>
>> When you burn out a rectifier in your alternator (like I have on
>> numerous occasions) then you are only putting out Two Phase to your
>> battery and system.
>
>The diodes are in the three phase alternator.
>
>A two phase alternator would be an inherently unbalanced load.
>

[Tarver Engineering]

"Big John" > wrote in message
...
> Tarver
>
> Yep.
>
> So.<G>
>
> Charged battery and ran load ok until I could get repaired.

That is the idea, fail safe.

[clare @ snyder.on .ca]

On Fri, 13 Feb 2004 08:03:34 -0800, "Tarver Engineering"
> wrote:

>
>"RU ok" > wrote in message
...
>> On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:
>
><snip of senile old fool>
>
>> You mean the alternator on my car isn't
>> three phase furnishing DC to charge the battery"?
>
>Yes, it is.
>
It is a 3 phase AC machine - the rectifiers make DC - which is DC no
mater how you slice it and dice it, and no matter what you roll it in.

[Tarver Engineering]

<clare @ snyder.on .ca> wrote in message
...
> On Fri, 13 Feb 2004 08:03:34 -0800, "Tarver Engineering"
> > wrote:
>
> >
> >"RU ok" > wrote in message
> ...
> >> On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:
> >
> ><snip of senile old fool>
> >
> >> You mean the alternator on my car isn't
> >> three phase furnishing DC to charge the battery"?
> >
> >Yes, it is.
> >
> It is a 3 phase AC machine - the rectifiers make DC - which is DC no
> mater how you slice it and dice it, and no matter what you roll it in.

Actually, no, but I'll let you ponder on the rest of the circuit.

[clare @ snyder.on .ca]

On Fri, 13 Feb 2004 19:43:56 -0800, "Tarver Engineering"
> wrote:

>
><clare @ snyder.on .ca> wrote in message
...
>> On Fri, 13 Feb 2004 08:03:34 -0800, "Tarver Engineering"
>> > wrote:
>>
>> >
>> >"RU ok" > wrote in message
>> ...
>> >> On Thu, 12 Feb 2004 22:28:52 -0800, Jim Weir > wrote:
>> >
>> ><snip of senile old fool>
>> >
>> >> You mean the alternator on my car isn't
>> >> three phase furnishing DC to charge the battery"?
>> >
>> >Yes, it is.
>> >
>> It is a 3 phase AC machine - the rectifiers make DC - which is DC no
>> mater how you slice it and dice it, and no matter what you roll it in.
>
>Actually, no, but I'll let you ponder on the rest of the circuit.
>
PLONK

[Cam]

I suppose if you want to be fussy, the DC will be lumpy every 120 degrees,
but hey, thats what lead acid batteries like being charged by....

Cam..

> >> >> You mean the alternator on my car isn't
> >> >> three phase furnishing DC to charge the battery"?
> >> >
> >> >Yes, it is.
> >> >
> >> It is a 3 phase AC machine - the rectifiers make DC - which is DC no
> >> mater how you slice it and dice it, and no matter what you roll it in.
> >
> >Actually, no, but I'll let you ponder on the rest of the circuit.
> >
> PLONK

[Tarver Engineering]

"Cam" > wrote in message
...
> I suppose if you want to be fussy, the DC will be lumpy every 120 degrees,
> but hey, thats what lead acid batteries like being charged by....

Rectified three phase into a battery makes a quiet DC source.

[Cy Galley]

I believe it is only 60° "lumpiness" as there are 6 diodes in the full wave
rectifying bridge.

"Cam" > wrote in message
...
> I suppose if you want to be fussy, the DC will be lumpy every 120 degrees,
> but hey, thats what lead acid batteries like being charged by....
>
> Cam..
>
> > >> >> You mean the alternator on my car isn't
> > >> >> three phase furnishing DC to charge the battery"?
> > >> >
> > >> >Yes, it is.
> > >> >
> > >> It is a 3 phase AC machine - the rectifiers make DC - which is DC no
> > >> mater how you slice it and dice it, and no matter what you roll it
in.
> > >
> > >Actually, no, but I'll let you ponder on the rest of the circuit.
> > >
> > PLONK
>
>

[Cam]

True.

Cam

"Cy Galley" > wrote in message
news:CNMXb.312257$I06.3161934@attbi_s01...
> I believe it is only 60° "lumpiness" as there are 6 diodes in the full
wave
> rectifying bridge.
>
> "Cam" > wrote in message
> ...
> > I suppose if you want to be fussy, the DC will be lumpy every 120
degrees,
> > but hey, thats what lead acid batteries like being charged by....
> >
> > Cam..

[Peter Gottlieb]

"Tarver Engineering" > wrote in message
...
>
> "Cam" > wrote in message
> ...
> > I suppose if you want to be fussy, the DC will be lumpy every 120
degrees,
> > but hey, thats what lead acid batteries like being charged by....
>
> Rectified three phase into a battery makes a quiet DC source.
>
>

No, not that quiet. Otherwise we wouldn't have "alternator whine." And
there is a "bump" every 60 degrees (full wave rectification). However, due
to the higher frequency of the ripple, 3 phase is easier to filter to make
pure DC. I imagine that's what everyone here means to say?