On 5/8/21 12:00 PM, cctalk-requ...@classiccmp.org wrote:
Message: 8 Date: Fri, 7 May 2021 21:59:08 + From: W2HX
To: Andrew Back , "General
Discussion: On-Topic and Off-Topic Posts"
Subject: RE: 400 Hz Message-ID:
Content-Type: text/plain; charset="utf-8" I will a
On 05/07/2021 06:55 PM, Fred Cisin via cctalk wrote:
Hmmm. If they ever use single phase, instead of 3 phase,
. . .
A4 (A above middle C) is nominally 440Hz, but not
everybody agrees.
NY Phil uses 442, Boston uses 441, and many argue for 432.
But, 400 would be A-flat. With a constant A fla
On 5/7/21 4:55 PM, Fred Cisin via cctalk wrote:
> Hmmm. If they ever use single phase, instead of 3 phase, . . .
>
> A4 (A above middle C) is nominally 440Hz, but not everybody agrees.
> NY Phil uses 442, Boston uses 441, and many argue for 432.
>
> But, 400 would be A-flat. With a constant A f
Hmmm. If they ever use single phase, instead of 3 phase, . . .
A4 (A above middle C) is nominally 440Hz, but not everybody agrees.
NY Phil uses 442, Boston uses 441, and many argue for 432.
But, 400 would be A-flat. With a constant A flat droning in the
background, . . .
aircraft.
73 Eugene W2HX
-Original Message-
From: cctalk On Behalf Of Andrew Back via cctalk
Sent: Wednesday, May 5, 2021 11:26 AM
To: cctalk@classiccmp.org
Subject: Re: 400 Hz
On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
Were the higher frequencies used because it directly effected
-
From: cctalk On Behalf Of Andrew Back via cctalk
Sent: Wednesday, May 5, 2021 11:26 AM
To: cctalk@classiccmp.org
Subject: Re: 400 Hz
On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
> Were the higher frequencies used because it directly effected the
> amount of time / duration in (fra
First, thank you to everyone who replied and gave me things to think
about and learn from.
On 5/5/21 9:26 AM, wrco...@wrcooke.net wrote:
Hope this helps.
Yes, indeed, very much. Thankfully, your description happened to mesh
with the weird way that my brain processes things and your message
Applying a square wave of 15kHz has harmonics up to 100kHz and more.
That means, that the current in these is more than 100 times bigger - BAM!
Additionally, output devices with really fast switching times can trigger
reflections back from the load, and these can potentially expose these
devi
Dr. Erik Baigar via cctalk wrote:
I've heard that. But why? It's not like the electronics we're
talking about actually runs on AC.
(a) Input filters often contain caps...
https://uk.tdk-lambda.com/content/faq/130796117766108286_FilterFAQ_how%20Image%201.jpg
With 50Hz or 60Hz they create a l
k
Note that VFDs are designed to run motors exclusively. They
approximate a sine wave with pulse width modulated 400 V pulses. DON'T
EVER try to run electronic gear with a VFD, at least without a massive
Yes, that is what I suggested; these filters are called "Sinus Filters"
in the field o
> On May 5, 2021, at 12:22 PM, Jon Elson wrote:
>
> On 05/05/2021 10:37 AM, Paul Koning via cctalk wrote:
>> Incidentally, a way to get three phase power at a frequency of your choice
>> is to use a "variable frequency drive". That's basically a high power solid
>> state inverter intended to
On 05/05/2021 10:37 AM, Paul Koning via cctalk wrote:
Incidentally, a way to get three phase power at a
frequency of your choice is to use a "variable frequency
drive". That's basically a high power solid state inverter
intended to drive three-phase motors with a chosen
frequency resulting in
..not to forget, that the 400Hz equipment was readily available
from powering aircraft on the ground before the engines take
over. So although not cheap, they where cheaper than a custom
design at an arbitrary new frequency
On 05/05/2021 10:07 AM, Grant Taylor via cctalk wrote:
I have found the Motor Generator thread to be fascinating
and enlightening. But it has made many a reference to the
400 Hz or other frequency much higher than mains line
frequency. Despite the comments about the frequency, I'm
still conf
> Incidentally, a way to get three phase power at a frequency of your
> choice is to use a "variable frequency drive".
Please be careful with this! Have quite some experience in building
three phase inverters from such small boxes for my various avionics
projects.
(1) The normal ones rect
On 5/5/21 8:37 AM, Paul Koning via cctalk wrote:
> Incidentally, a way to get three phase power at a frequency of your
> choice is to use a "variable frequency drive". That's basically a
> high power solid state inverter intended to drive three-phase motors
> with a chosen frequency resulting in
On 5/5/21 8:37 AM, Paul Koning via cctalk wrote:
> Incidentally, a way to get three phase power at a frequency of your choice is
> to use a "variable frequency drive". That's basically a high power solid
> state inverter intended to drive three-phase motors with a chosen frequency
> resulting
..not to forget, that the 400Hz equipment was readily available
from powering aircraft on the ground before the engines take
over. So although not cheap, they where cheaper than a custom
design at an arbitrary new frequency
> On May 5, 2021, at 11:25 AM, Andrew Back via cctalk
> wrote:
>
> On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
>
>> Were the higher frequencies used because it directly effected the amount
>> of time / duration in (fractions of) seconds between peaks of rectified
>> (but not yet smoo
On 5/5/21 8:07 AM, Grant Taylor via cctalk wrote:
> I have found the Motor Generator thread to be fascinating and
> enlightening. But it has made many a reference to the 400 Hz or other
> frequency much higher than mains line frequency. Despite the comments
> about the frequency, I'm still confus
On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
> Were the higher frequencies used because it directly effected the amount
> of time / duration in (fractions of) seconds between peaks of rectified
> (but not yet smoothed) power?
Haven't read the rest of the thread and so at the risk of being
> On May 5, 2021, at 11:07 AM, Grant Taylor via cctalk
> wrote:
>
> I have found the Motor Generator thread to be fascinating and enlightening.
> But it has made many a reference to the 400 Hz or other frequency much higher
> than mains line frequency. Despite the comments about the frequ
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