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Switch-Mode Transformer

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axro

New Member
Is it possible to take a transformer out of a SMPS and use it to make a linear power supply?
 

Hero999

Banned
A SMPS transformer works at 20kHz to 200kHz, a mains transformer works at just 50Hz to 60Hz.

If you connect an SMPS transformer directly to the mains, it will saturate and blow up or take out the fuse or circuit breaker (whichever happens faster).
 

axro

New Member
A SMPS transformer works at 20kHz to 200kHz, a mains transformer works at just 50Hz to 60Hz.

If you connect an SMPS transformer directly to the mains, it will saturate and blow up or take out the fuse or circuit breaker (whichever happens faster).
Is there anything else that can be done with a SMPS transformer?

Are Switch-mode PSU's out of the realm of the hobbiest? I rarely see any Switch mode transformers and it's difficult to find schematics for it on the net.
 
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Hero999

Banned
Is there anything else that can be done with a SMPS transformer?
Yes, it can be re-wound and used as an inductor or transformer in your own supply.

An example might be to power a fluorescent tube from a car battery.

Are Switch-mode PSU's out of the realm of the hobbiest?
Mains power SMPSes really are out of the realm of the hobbyist for safety reasons but DC-DC converters aren't.
 

axro

New Member
Thats kind of disappointing. Seems like most of the salvage equipment I have is switch-mode, so I have alot of transformers that I can't do anything useful with.
 

bountyhunter

Well-Known Member
Is it possible to take a transformer out of a SMPS and use it to make a linear power supply?
It depends what frequency range it was designed for. Most switcher Xformers are designed to run at frequencies of 50kHz and up so they are useless at 60 Hz.
 

bountyhunter

Well-Known Member
In what way are they different?
The core material and design is such that they have low loss at very fast switching frequencies, but they also saturate VERY rapidly (and at relatively low flux densities) so they can't be used at low frequencies like an iron core transformer can.
 

tcmtech

Banned
Most Helpful Member
Mains power SMPSes really are out of the realm of the hobbyist for safety reasons
That depends on your level of hobby! ;)

My hobbies use killowatts more often than watts.:eek: :D
DCP01788.JPG

20 Kw Grid tie inverter under costruction if your wondering. 100 - 400 VDC input 240 VAC output with direct line connect too! All recycled parts as well! :D :)

Those little SMPS transformers have loads of alternative uses if you know how to use them. Use a basic switch mode driver IC and you can do all sorts of stuff with them. Skills alowing of course! :)
 

pfofit

Active Member
Love that bench.

If you ever clean up, you'll never find anything.

Well, at least that's what happens to me.
 

RCinFLA

Well-Known Member
It takes a bit of learning to build switch mode power supplies. Unlike 60 Hz transformers which you can pretty much assume same silicon-iron core material, switch mode transformer core material can be a wide range of material depending on frequency of switching and type of switcher.

If you want to get into it, here is a source for cores.

Ferrite: E Cores
 

bountyhunter

Well-Known Member
That depends on your level of hobby! ;)

My hobbies use killowatts more often than watts.:eek: :D
I always hated that stuff. The closest I came to dying was when I had to design a traveling wave tube supply that was about 10kV but with serious knock down power. TWT supplies have to deliver big peak currents so they all have a huge poly film storage cap on the output. That SOB unloaded on me one day and knocked me ten feet backwards into a wall. I developed a heart arrhythmia soon after and I still think it was because of it. Real nice company to work for: when I got sick, they fired me.
 
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Hero999

Banned
Were you a union member? You should have sued.
 

bountyhunter

Well-Known Member
Were you a union member? You should have sued.
Engineers have no unions, you are at the mercy of sudden termination for no cause. That was before the ADA, but a serious illness probably doesn't qualify as a disability anyway. It was a really rotten thing to do, but I was actually relieved since the diagnosis of cardiomyopathy was pretty grim and I was happy to be able to get more rest and try to get better. Which I did, no thanks to those dip sticks. No worries, Joe Varozza and his buddies will have the front rows of seats reserve for them on the express bus to hell.
 
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