https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 How does the mass of a transformer scale with frequency? I want to make a 120v 400 Hz power supply. I might boost my 48v up to 200DC and use an isolated h-bridge out to the load, or we could put the bridge down at 48v and boost with a biggish transformer. I'll have lots of air flow, so maybe I can push things some too. -- I yam what I yam - Popeye
magnetics question
Started by ●April 6, 2022
Reply by ●April 6, 20222022-04-06
On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote:> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 > > How does the mass of a transformer scale with frequency? > > I want to make a 120v 400 Hz power supply. I might boost my 48v up to > 200DC and use an isolated h-bridge out to the load, or we could put > the bridge down at 48v and boost with a biggish transformer. > > I'll have lots of air flow, so maybe I can push things some too.Weight is almost linear with power, and inversely with frequency. When I needed a 115V 400Hz for DO-160 aviation equipment development, I ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier module, and an extra mains transformer (used in reverse) for the 115V output. Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX with some resistors) to create the required brownout and dropout profiles. The customer was so amused they ordered some for their production and test line (until then, they used a gigantic motor + 400Hz dynamo in the basement to get 400 Hz). Arie
Reply by ●April 6, 20222022-04-06
On Wed, 6 Apr 2022 18:24:49 +0200, Arie de Muijnck <eternal.september@ademu.com> wrote:>On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote: >> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 >> >> How does the mass of a transformer scale with frequency? >> >> I want to make a 120v 400 Hz power supply. I might boost my 48v up to >> 200DC and use an isolated h-bridge out to the load, or we could put >> the bridge down at 48v and boost with a biggish transformer. >> >> I'll have lots of air flow, so maybe I can push things some too. > >Weight is almost linear with power, and inversely with frequency. > >When I needed a 115V 400Hz for DO-160 aviation equipment development, I >ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): >Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier >module, and an extra mains transformer (used in reverse) for the 115V >output. >Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX >with some resistors) to create the required brownout and dropout >profiles. The customer was so amused they ordered some for their >production and test line (until then, they used a gigantic motor + 400Hz >dynamo in the basement to get 400 Hz). > >ArieI think so... for a given core, power scales linearly with frequency. A simple scribble with a 4-winding transformer suggests that. Thanks John -- I yam what I yam - Popeye
Reply by ●April 6, 20222022-04-06
On 6.4.22 19.33, jlarkin@highlandsniptechnology.com wrote:> On Wed, 6 Apr 2022 18:24:49 +0200, Arie de Muijnck > <eternal.september@ademu.com> wrote: > >> On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote: >>> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 >>> >>> How does the mass of a transformer scale with frequency? >>> >>> I want to make a 120v 400 Hz power supply. I might boost my 48v up to >>> 200DC and use an isolated h-bridge out to the load, or we could put >>> the bridge down at 48v and boost with a biggish transformer. >>> >>> I'll have lots of air flow, so maybe I can push things some too. >> >> Weight is almost linear with power, and inversely with frequency. >> >> When I needed a 115V 400Hz for DO-160 aviation equipment development, I >> ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): >> Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier >> module, and an extra mains transformer (used in reverse) for the 115V >> output. >> Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX >> with some resistors) to create the required brownout and dropout >> profiles. The customer was so amused they ordered some for their >> production and test line (until then, they used a gigantic motor + 400Hz >> dynamo in the basement to get 400 Hz). >> >> Arie > > I think so... for a given core, power scales linearly with frequency. > A simple scribble with a 4-winding transformer suggests that. > > Thanks > > JohnYou have to be prepared for larger core losses due to the higher frequency if you use the same core material. The higher frequency core materials are bulkier for the same power due to the smaller permeability. I'd use a 400 Hz transformer. -- -TV
Reply by ●April 6, 20222022-04-06
On 2022-04-06 18:33, jlarkin@highlandsniptechnology.com wrote:> On Wed, 6 Apr 2022 18:24:49 +0200, Arie de Muijnck > <eternal.september@ademu.com> wrote: > >> On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote: >>> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 >>> >>> How does the mass of a transformer scale with frequency? >>> >>> I want to make a 120v 400 Hz power supply. I might boost my 48v up to >>> 200DC and use an isolated h-bridge out to the load, or we could put >>> the bridge down at 48v and boost with a biggish transformer. >>> >>> I'll have lots of air flow, so maybe I can push things some too. >> >> Weight is almost linear with power, and inversely with frequency. >> >> When I needed a 115V 400Hz for DO-160 aviation equipment development, I >> ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): >> Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier >> module, and an extra mains transformer (used in reverse) for the 115V >> output. >> Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX >> with some resistors) to create the required brownout and dropout >> profiles. The customer was so amused they ordered some for their >> production and test line (until then, they used a gigantic motor + 400Hz >> dynamo in the basement to get 400 Hz). >> >> Arie > > I think so... for a given core, power scales linearly with frequency. > A simple scribble with a 4-winding transformer suggests that. > > Thanks > > JohnYes, which is exactly why switching PSU's are now the standard. The cost saving in iron (ferrite) and copper and capacitors, and all transport costs, far outweighs (pun intended) the cost of the semiconductors. And why airplanes use 400 Hz - the tiny transformers I had designed in in the product were amusing, 8 times smaller than the usual 50 hz versions. Arie
Reply by ●April 6, 20222022-04-06
On 2022-04-06 18:44, Tauno Voipio wrote:> On 6.4.22 19.33, jlarkin@highlandsniptechnology.com wrote: >> On Wed, 6 Apr 2022 18:24:49 +0200, Arie de Muijnck >> <eternal.september@ademu.com> wrote: >> >>> On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote: >>>> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 >>>> >>>> How does the mass of a transformer scale with frequency? >>>> >>>> I want to make a 120v 400 Hz power supply. I might boost my 48v up to >>>> 200DC and use an isolated h-bridge out to the load, or we could put >>>> the bridge down at 48v and boost with a biggish transformer. >>>> >>>> I'll have lots of air flow, so maybe I can push things some too. >>> >>> Weight is almost linear with power, and inversely with frequency. >>> >>> When I needed a 115V 400Hz for DO-160 aviation equipment development, I >>> ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): >>> Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier >>> module, and an extra mains transformer (used in reverse) for the 115V >>> output. >>> Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX >>> with some resistors) to create the required brownout and dropout >>> profiles. The customer was so amused they ordered some for their >>> production and test line (until then, they used a gigantic motor + 400Hz >>> dynamo in the basement to get 400 Hz). >>> >>> Arie >> >> I think so... for a given core, power scales linearly with frequency. >> A simple scribble with a 4-winding transformer suggests that. >> >> Thanks >> >> John > > > You have to be prepared for larger core losses due to the > higher frequency if you use the same core material. > > The higher frequency core materials are bulkier > for the same power due to the smaller permeability. > > I'd use a 400 Hz transformer. >Which is why I used (Amplimo) toroids - they are good until several kHz. Arie
Reply by ●April 6, 20222022-04-06
On a sunny day (Wed, 06 Apr 2022 08:53:22 -0700) it happened jlarkin@highlandsniptechnology.com wrote in <2fdr4hdk4ni4l5ds6vb97hkgtvbiufs47u@4ax.com>:>https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 > >How does the mass of a transformer scale with frequency?When I wind some transformer I usulally look at the no load primary inductance so it is high eneough not to drain power, Then for that L and the given Core material I get number of turns Many of thsoe core sellers specify a core size for a given power. The load current, number of turns and wire diameter will give you weight of the coils. That weight is to be added to the core material for total 'mass' if that is what you mean.>I want to make a 120v 400 Hz power supply. I might boost my 48v up to >200DC and use an isolated h-bridge out to the load, or we could put >the bridge down at 48v and boost with a biggish transformer.Why not balanced with 2 transistors and a transformer 48 to 120 V ___________ T1 ______ ||( )||( 48 V +--- ||( 120 V ______)||( T2 ||(__________ Dunno how accurate it needs to be, replace the T1 T2 with thyristors, tune it with a big cap and make it self-oscillating? ___________ T1________________ ||( | )||( === 48 V +--- ||( 120 V _|______________)||( T2 ____ ||(__________ feedback ____) || Or use the almost all knowing google: https://www.google.com/search?q=48V+DC+to+120V+AC+400Hz++circuit+diagram select 'images' for circuits.>I'll have lots of air flow, so maybe I can push things some too.Yes was storm here too
Reply by ●April 6, 20222022-04-06
On a sunny day (Wed, 6 Apr 2022 18:24:49 +0200) it happened Arie de Muijnck <eternal.september@ademu.com> wrote in <t2kesh$3t5$1@dont-email.me>:>On 2022-04-06 17:53, jlarkin@highlandsniptechnology.com wrote: >> https://www.dropbox.com/s/jnb3jmw8rcmdeir/XfmrScatter.JPG?raw=1 >> >> How does the mass of a transformer scale with frequency? >> >> I want to make a 120v 400 Hz power supply. I might boost my 48v up to >> 200DC and use an isolated h-bridge out to the load, or we could put >> the bridge down at 48v and boost with a biggish transformer. >> >> I'll have lots of air flow, so maybe I can push things some too. > >Weight is almost linear with power, and inversely with frequency. > >When I needed a 115V 400Hz for DO-160 aviation equipment development, I >ordered a 100W amplifier set from Amplimo (https://www.amplimo.nl/): >Mains transformer (toroid 115/230V in), rectifier, capacitors, amplifier >module, and an extra mains transformer (used in reverse) for the 115V >output. >Added a 400 Hz oscillator with a timer controlled gain control (4051 MUX >with some resistors) to create the required brownout and dropout >profiles. The customer was so amused they ordered some for their >production and test line (until then, they used a gigantic motor + 400Hz >dynamo in the basement to get 400 Hz). > >ArieYes, that is how I make 60 Hz here in 50 Hz land, 100 W audio amp 60 Hz from PC signal generator in 50 Hz mains transformer connected the other way around. Not very efficient, but nice sinewave and no harmonics. A simple raspberry followed by a low pass could drive that (raspi audio out is some PWM I think, sure has RF on it).
Reply by ●April 6, 20222022-04-06
In article <t2ki95$afi$1@dont-email.me>, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>Yes, that is how I make 60 Hz here in 50 Hz land, >100 W audio amp 60 Hz from PC signal generator >in 50 Hz mains transformer connected the other way around. >Not very efficient, but nice sinewave and no harmonics. >A simple raspberry followed by a low pass could drive that >(raspi audio out is some PWM I think, sure has RF on it).It's pretty easy to connect a $10-or-so I2S audio DAC board to a Pi, rather than using the on-board audio DAC. The ones I've been using (based on Ti/Burr-Brown PCM-series DAC chips) put out a pretty clean waveform - one can add a very simple low-pass to block noise up above a few hundred kHz if necessary.
Reply by ●April 6, 20222022-04-06
Arie de Muijnck wrote:> Yes, which is exactly why switching PSU's are now the standard. The cost > saving in iron (ferrite) and copper and capacitors, and all transport > costs, far outweighs (pun intended) the cost of the semiconductors.Their regulation capability is far better than that of the more conventional PSUs.> And why airplanes use 400 Hz - the tiny transformers I had designed in > in the product were amusing, 8 times smaller than the usual 50 hz versions.But why 400 then? A typical scaling factor would be 10, so 500Hz should be expected. Instead, they have selected the odd value of 8. Backward compatibility with an arbitrarily selected frequency back in the medieval times? Best regards, Piotr
