On Thu, 6 Aug 2020 03:57:22 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
>Cydrome Leader is an IDIOT wrote:
>
>================================
>
>
>> >>
>> >> > So I ran it for a few hours with 10 amps DC in the primary. Temp rise
>> >> > was about 26C in free air. I think people design transformers for
>> >> > equal copper loss in the primary and secondary, so temp rise would
>> >> > double when loaded in the system.
>> >>
>> >> What about the heat generated by losses in the secondary?
>> >
>> >
>> > ** Doubles the temp rise - as JL just claimed.
>>
>> It sounded like the double the heat assumption was from the 50% of losses
>> being in the iron, when the transformer is used with AC.
>
>** You on drugs ??
I am!
--
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
Reply by ●August 8, 20202020-08-08
On Sat, 8 Aug 2020 05:54:48 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:
>jlarkin@highlandsniptechnology.com wrote:
>> On Thu, 6 Aug 2020 06:57:07 +0000 (UTC), Cydrome Leader
>> <presence@MUNGEpanix.com> wrote:
>>
>>>jlarkin@highlandsniptechnology.com wrote:
>>>> On Wed, 5 Aug 2020 01:21:10 -0700 (PDT), Phil Allison
>>>> <pallison49@gmail.com> wrote:
>>>>
>>>>>Cydrome Leader is Funny:
>>>>>
>>>>>=======================
>>>>>>
>>>>>> > So I ran it for a few hours with 10 amps DC in the primary. Temp rise
>>>>>> > was about 26C in free air. I think people design transformers for
>>>>>> > equal copper loss in the primary and secondary, so temp rise would
>>>>>> > double when loaded in the system.
>>>>>>
>>>>>> What about the heat generated by losses in the secondary?
>>>>>
>>>>>
>>>>>** Doubles the temp rise - as JL just claimed.
>>>>>
>>>>>
>>>>>> > https://www.dropbox.com/s/ylm8dc1e14dwv7y/P900_Xfmr_Thermal.jpg?raw=1
>>>>>> >
>>>>>> > https://www.dropbox.com/s/5b55ybfoq2pkp9v/P900_Xfmr_Thermal_2.jpg?raw=1
>>>>>>
>>>>>> You can even see on the label (looks sort of like a Noratel) the input is
>>>>>> 266VA and output is rated 240VA. So depending on power factor at full
>>>>>> load, it could be upto 26 watts of loss, although I doubt a toroid that
>>>>>> size would have such a poor efficiency. The iron losses will surely be
>>>>>> less than 50% on a toroid. Maybe the maker can tell you the ratio?
>>>>>>
>>>>
>>>> This transformer was made for us by Amgis. I specified it so I know
>>>> the ratios: 1 : 1.4 : 1.4 : 1.4 : 1.4. We have a relay board that
>>>> switches the secondaries to get four output voltage ranges.
>>>
>>>Are these ratios exact or is there a fudge factor for losses at rated
>>>load?
>>
>> Exact turns ratio. We know the other parameters: wire resistance, mag
>> inductance, leakage inductance, SRF, saturation. We plug all that into
>> the system Spice model.
>
>How did that work out? Did you give rought specs and the then the
>manufacture provided full expected specs?
Pretty much. I specified the voltages, power levels, turns ratio,
frequency range, and suggested a stock Hammond part as being about the
right size and mounting. The Hammond part guided me as to what was
reasonable; I didn't have to do any real magnetics calculations, just
scale that transformer a little. They responded with a more detailed
spec with resistances, inductances, wire colors, things like that.
That looked good so I told them to go.
>
>> Just curious. Retired transformer designer friend seemed to spend a
>>>bit of his time trying to get "the facts" from customers to make designs
>>>that would actually work under load. The stubborn customers would get full
>>>production runs of stuff that met specs, but didn't work for the
>>>application.
>>>
>>>>>** PF has no effect - VA is all that matters, effectively just the RMS current. Iron losses are a watt or so per kg or iron. I mag is tiny.
>>>>>
>>>>>So 20 watts copper loss, 6 watts for iron.
>>>>>
>>>>>Regulation about 8%.
>>>>>
>>>>>Toriods are very simple.
>>>>>
>>>>>
>>>>>.... Phil
>>>>
>>>> Unloaded, the AC operating primary current is essentially zero, so I
>>>> don't think core loss is significant.
>>>>
>>>> As an alternator simulator, voltage increases with frequency, which
>>>> keeps Imag low on the low end.
>>>>
>>>> It's a weird application. We specialize in weird.
>>>
>>>Was amgis friendly about making samples?
>>
>> Not free samples, but I didn't ask for that. We placed a PO that
>> included a few first-articles for verification, with the rest shipped
>> on approval.
>
>Sounds reasonable.
I'd used them before, and the production requirement was real, so that
was a good way to work with them.
--
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
Reply by Phil Allison●August 8, 20202020-08-08
Cydrome Leader is a retarded NUT case wrote:
===========================================
> >
> > ** You on drugs ??
> >
> >
> > ** My god you are stupid.
> >
> > Max heat loss happens at max load, always.
>
> Wow, you're finally catching up.
>
** I'm way ahead of morons lie you.
> Now go ahead and re-read my comment about
> the sillyness of VA in and VA out ratings on small toroidal transformers.
** You never made any.
.... Phil
Reply by Cydrome Leader●August 8, 20202020-08-08
legg <legg@nospam.magma.ca> wrote:
> On Thu, 6 Aug 2020 16:41:03 -0700 (PDT), Phil Allison
> <pallison49@gmail.com> wrote:
>
>>legg wrote:
>>
>>==========
>>
>>
>>> For windings, it's a 'fill factor'.
>>>
>>> If you check the ratio of copper vs air in the inner
>>> diameter of a toroid, as the fill approaches a certain
>>> percentage, you'll see a diminishing return for agravated
>>> difficulty in fabrication.
>>
>>** Cost is everything in manufacture.
>>
>>But as here like to consider what physics allows, it is clearly a fact that filling a toroidal with as much copper as possible maximises the VA for a given core.
>>
>>This IS the practice for all other types of core shape.
>>
>>Most toroidals are low and flat - again not optimum but liked by many customers. Same goes for R-cores and U cores which result in low height products.
>>
>>
>>
>>.... Phil
>
> Those last few turns also have the longest length
> per turn, further diminishing their 'return'.
>
> The 'practice' is to assume a fill factor of less
> than 80%, to allow for insulation, wire shape and
> cover. For mains voltage wall thickness, creepage
> spacing, and bobbin tolerancing, it's even worse.
>
> Toroids depend upon 3xlayer film overlapping weave for
> reinforced layering and core or outer wrap, though
> some cores use fitted caps at the expense of efficiency.
>
> Low and flat toroids are a 'style' (at the expense of
> efficiency) - the most efficient physical ratio being
> roughly 2.2:1 / OD:H.
>
> High frequency stuff . . . .
>
> RL
> Cydrome Leader is an IDIOT wrote:
>
> ================================
>
>
>> >>
>> >> > So I ran it for a few hours with 10 amps DC in the primary. Temp rise
>> >> > was about 26C in free air. I think people design transformers for
>> >> > equal copper loss in the primary and secondary, so temp rise would
>> >> > double when loaded in the system.
>> >>
>> >> What about the heat generated by losses in the secondary?
>> >
>> >
>> > ** Doubles the temp rise - as JL just claimed.
>>
>> It sounded like the double the heat assumption was from the 50% of losses
>> being in the iron, when the transformer is used with AC.
>
> ** You on drugs ??
>
>
>> Even if you
>> double the primary resistive loses to account for the secondary, the core
>> is still being left out. That's how I read it.
>
> ** JL neglected it as he knows it is trivial.
>
>
>>
>> As for the PF has no effect statement, I've never really understood the
>> point on the VA in and VA out ratings on some toroidal transformers.
>> Isolation transfomers are usually marked in a more sensible way like
>> "input 120VAC 8.4A, output 120VAC 8.0A". While these are safe use ratings,
>> it still doesn't answer the question about efficiency at no to full load.
>> You can only guess the worst case heat losses.
>>
>
> ** My god you are stupid.
>
> Max heat loss happens at max load, always.
Wow, you're finally catching up. Now go ahead and re-read my comment about
the sillyness of VA in and VA out ratings on small toroidal transformers.
Reply by Cydrome Leader●August 8, 20202020-08-08
jlarkin@highlandsniptechnology.com wrote:
> On Thu, 6 Aug 2020 06:57:07 +0000 (UTC), Cydrome Leader
> <presence@MUNGEpanix.com> wrote:
>
>>jlarkin@highlandsniptechnology.com wrote:
>>> On Wed, 5 Aug 2020 01:21:10 -0700 (PDT), Phil Allison
>>> <pallison49@gmail.com> wrote:
>>>
>>>>Cydrome Leader is Funny:
>>>>
>>>>=======================
>>>>>
>>>>> > So I ran it for a few hours with 10 amps DC in the primary. Temp rise
>>>>> > was about 26C in free air. I think people design transformers for
>>>>> > equal copper loss in the primary and secondary, so temp rise would
>>>>> > double when loaded in the system.
>>>>>
>>>>> What about the heat generated by losses in the secondary?
>>>>
>>>>
>>>>** Doubles the temp rise - as JL just claimed.
>>>>
>>>>
>>>>> > https://www.dropbox.com/s/ylm8dc1e14dwv7y/P900_Xfmr_Thermal.jpg?raw=1
>>>>> >
>>>>> > https://www.dropbox.com/s/5b55ybfoq2pkp9v/P900_Xfmr_Thermal_2.jpg?raw=1
>>>>>
>>>>> You can even see on the label (looks sort of like a Noratel) the input is
>>>>> 266VA and output is rated 240VA. So depending on power factor at full
>>>>> load, it could be upto 26 watts of loss, although I doubt a toroid that
>>>>> size would have such a poor efficiency. The iron losses will surely be
>>>>> less than 50% on a toroid. Maybe the maker can tell you the ratio?
>>>>>
>>>
>>> This transformer was made for us by Amgis. I specified it so I know
>>> the ratios: 1 : 1.4 : 1.4 : 1.4 : 1.4. We have a relay board that
>>> switches the secondaries to get four output voltage ranges.
>>
>>Are these ratios exact or is there a fudge factor for losses at rated
>>load?
>
> Exact turns ratio. We know the other parameters: wire resistance, mag
> inductance, leakage inductance, SRF, saturation. We plug all that into
> the system Spice model.
How did that work out? Did you give rought specs and the then the
manufacture provided full expected specs?
> Just curious. Retired transformer designer friend seemed to spend a
>>bit of his time trying to get "the facts" from customers to make designs
>>that would actually work under load. The stubborn customers would get full
>>production runs of stuff that met specs, but didn't work for the
>>application.
>>
>>>>** PF has no effect - VA is all that matters, effectively just the RMS current. Iron losses are a watt or so per kg or iron. I mag is tiny.
>>>>
>>>>So 20 watts copper loss, 6 watts for iron.
>>>>
>>>>Regulation about 8%.
>>>>
>>>>Toriods are very simple.
>>>>
>>>>
>>>>.... Phil
>>>
>>> Unloaded, the AC operating primary current is essentially zero, so I
>>> don't think core loss is significant.
>>>
>>> As an alternator simulator, voltage increases with frequency, which
>>> keeps Imag low on the low end.
>>>
>>> It's a weird application. We specialize in weird.
>>
>>Was amgis friendly about making samples?
>
> Not free samples, but I didn't ask for that. We placed a PO that
> included a few first-articles for verification, with the rest shipped
> on approval.
Sounds reasonable.
Reply by Jasen Betts●August 8, 20202020-08-08
On 2020-08-07, dagmargoodboat@yahoo.com <dagmargoodboat@yahoo.com> wrote:
> On Wednesday, August 5, 2020 at 7:38:00 PM UTC-4, John Larkin wrote:
>> On Wed, 5 Aug 2020 23:32:02 +0200, Piotr Wyderski
>> <peter.pan@neverland.mil> wrote:
>>
>> >jlarkin@highlandsniptechnology.com wrote:
>> >
>> >> I think people design transformers for
>> >> equal copper loss in the primary and secondary
>> >
>> >BTW, what is the source of this and similar rules of thumb (e.g. equal
>> >copper and core losses)? Logic says that one should always design for
>> >minimal total losses, given the economic constraints.
>> >
>> > Best regards, Piotr
>>
>> I don't think transformers are usually designed for equal core and
>> copper losses. This one runs cold at full AC voltage but no load.
>>
>> They are designed for equal primary and secondary copper losses at
>> full load, I think.
>>
>> Cooling depends on surface area. You get more surface area by adding
>> more copper, and that relationship is not linear (the volume-surface
>> thing, like mice and elephants) so core loss might require a lot of
>> expensive copper.
>
> I'm intrigued by the matrix transformer concept: two transformers
> with primaries in series and secondaries in parallel have both 1/4th
> the i^2*r losses each, and more dissipation surface per watt compared
> to a single giant lump of copper buried in steel.
It seems to me that you'd get most of those benefits buy just using a
single transforer of twice the mass. I think you may be counting
some of the gains twice.
--
Jasen.
Reply by legg●August 7, 20202020-08-07
On Fri, 7 Aug 2020 17:15:53 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
>legg wrote more absurd crap:
>
>============================
>
>>
>> >> For windings, it's a 'fill factor'.
>> >>
>> >> If you check the ratio of copper vs air in the inner
>> >> diameter of a toroid, as the fill approaches a certain
>> >> percentage, you'll see a diminishing return for agravated
>> >> difficulty in fabrication.
>> >
>> >** Cost is everything in manufacture.
>> >
>> >But as here like to consider what physics allows, it is clearly a fact that filling a toroidal with as much copper as possible maximises the VA for a given core.
>> >
>> >This IS the practice for all other types of core shape.
>> >
>> >Most toroidals are low and flat - again not optimum but liked by many customers. Same goes for R-cores and U cores which result in low height products.
>>
>>
>> Those last few turns also have the longest length
>> per turn, further diminishing their 'return'.
>>
>
>** What utterly stupid garbage.
>
>One fills the available space by using the heaviest gauge wire possible - not by increasing the turns - that is already set by the core cross section, voltage and frequency.
>
>Yo have no point to make and just post bullshit for the sake of having the last word and big noting your pathetic self.
>
>FOAD you ridiculous ass.
>
>
>..... Phil
If the MLT drops 20%, You get the same loss with 20% reduction
in copper x-section.
Not so?
RL
Reply by Phil Allison●August 7, 20202020-08-07
legg wrote more absurd crap:
============================
>
> >> For windings, it's a 'fill factor'.
> >>
> >> If you check the ratio of copper vs air in the inner
> >> diameter of a toroid, as the fill approaches a certain
> >> percentage, you'll see a diminishing return for agravated
> >> difficulty in fabrication.
> >
> >** Cost is everything in manufacture.
> >
> >But as here like to consider what physics allows, it is clearly a fact that filling a toroidal with as much copper as possible maximises the VA for a given core.
> >
> >This IS the practice for all other types of core shape.
> >
> >Most toroidals are low and flat - again not optimum but liked by many customers. Same goes for R-cores and U cores which result in low height products.
>
>
> Those last few turns also have the longest length
> per turn, further diminishing their 'return'.
>
** What utterly stupid garbage.
One fills the available space by using the heaviest gauge wire possible - not by increasing the turns - that is already set by the core cross section, voltage and frequency.
Yo have no point to make and just post bullshit for the sake of having the last word and big noting your pathetic self.
FOAD you ridiculous ass.
..... Phil
Reply by Tabby●August 7, 20202020-08-07
On Friday, 7 August 2020 22:09:56 UTC+1, John Larkin wrote:
> On Fri, 7 Aug 2020 13:51:22 -0700 (PDT), dagmargoodboat@yahoo.com
> wrote:
> >On Friday, August 7, 2020 at 11:03:04 AM UTC-4, jla...@highlandsniptechnology.com wrote:
Years ago I discovered from hipot testing transformers that it was too easy for them to suddenly not withstand as much voltage any more. The 1 person manufacturing line swore nothing had been changed.
NT