Electronics Lab Philippines

Looking for an isolation transformer

Looking for an isolation transformer
« on: September 22, 2019, 09:38:56 AM »
I am struggling to find an isolation transformer to buy. I would like to have an isolation transformer because I need to use the oscilloscope to measure a device-under-test which is directly powered by the mains. And I want to avoid creating a ground loop with my oscilloscope probes, which would destroy the oscilloscope.
The isolation transformer shall have a 230V input and a 230V or 220V output. 500W is more than enough. And it should come in a case, such that I could use it on my bench.

I was hoping to find something around a price of ~P3,000.
I once found a step-down transformer which also offers a 220V outlet. At TrueValue. And I bought it. But when I opened the case, I found that it was an auto-transformer. Which means that there is no secondary winding (only a primary one), and hence no galvanic isolation between input and output.
Now I am thinking whether I could simply purchase one of these AVRs they are selling in all DIY shops in the Philippines. As long as they have 2 separated windings (a primary one and a secondary one), that should be enough to qualify as an isolation transformer. I would just need to check if the secondary side outlet has its ground isolated from the primary side ground. And if necessary, cut off that connection. But unfortunately it's impossible to find any schematics or any information in the user manual or on the internet, whether a specific AVR model truly has 2 separated windings or not.

Any other ideas?

Offline >>>^żżż^<<<

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Re: Looking for an isolation transformer
« Reply #1 on: September 23, 2019, 04:47:40 AM »
gawa ka na lang boss
http://www.elab.ph/index.php?topic=52236.0 TF?
http://www.elab.ph/index.php?topic=41860 ? ? ? DIY traffo Test Build Uli
http://www.elab.ph/index.php?topic=33717  I2c / spi programmer
http://www.elab.ph/index.php?topic=37150.0 Lcr esr makikigulo rin ba kayo ??? Test Build
http://www.elab.ph/index.php?topic=29963.0 Esr collection na malamig
http://www.elab.ph/index.php?topic=25854.0 Basic C++ Programming Tutorials by Prof Asimo
We only live once,treasure those we love, make friends not enemies and keep our family closer. And we will be at peace.
FISH

Offline labgruppen

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Re: Looking for an isolation transformer
« Reply #2 on: September 23, 2019, 02:22:41 PM »
I am struggling to find an isolation transformer to buy. I would like to have an isolation transformer because I need to use the oscilloscope to measure a device-under-test which is directly powered by the mains. And I want to avoid creating a ground loop with my oscilloscope probes, which would destroy the oscilloscope.
The isolation transformer shall have a 230V input and a 230V or 220V output. 500W is more than enough. And it should come in a case, such that I could use it on my bench.

I was hoping to find something around a price of ~P3,000.
I once found a step-down transformer which also offers a 220V outlet. At TrueValue. And I bought it. But when I opened the case, I found that it was an auto-transformer. Which means that there is no secondary winding (only a primary one), and hence no galvanic isolation between input and output.
Now I am thinking whether I could simply purchase one of these AVRs they are selling in all DIY shops in the Philippines. As long as they have 2 separated windings (a primary one and a secondary one), that should be enough to qualify as an isolation transformer. I would just need to check if the secondary side outlet has its ground isolated from the primary side ground. And if necessary, cut off that connection. But unfortunately it's impossible to find any schematics or any information in the user manual or on the internet, whether a specific AVR model truly has 2 separated windings or not.

Any other ideas?

you could inquire from R.O.K.S... they accept made to order transformers.. they might also have surplus ones that fit your needs..

Offline congressman

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Re: Looking for an isolation transformer
« Reply #3 on: September 25, 2019, 09:50:11 PM »
mag diy ka na lang po. micro wave transformer 220v in 220v out.
2 coil series/ in....2coil series/ out
Peace!

Offline bravokilo

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Re: Looking for an isolation transformer
« Reply #4 on: October 05, 2019, 07:32:22 AM »
Buy two large 220 in and 12,24, 0r even 48V out. Back to back the traffos. ()connect the secondaries). One 220 is in and he oher , out.

Offline bravokilo

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Re: Looking for an isolation transformer
« Reply #5 on: October 05, 2019, 09:32:23 AM »
At Deeco, the biggestt isolaed traffo is 24 V at 12 amps. 12x24=VA. may be small if you need 500 W. You can hae one made. If you have a step down 110V, they can make that isolated by splitting in the center, one half at 110V will primary and the other secondary. Then use a step up to power you 220v device. Reverse the P and S in anoher stepdown traffo.


Offline >>>^żżż^<<<

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Re: Looking for an isolation transformer
« Reply #6 on: October 24, 2019, 07:03:53 PM »
DIY ko malaki rin gastos baka 3 to 5k hanggang ngayon di parin tapos.  ;D
http://www.elab.ph/index.php?topic=52236.0 TF?
http://www.elab.ph/index.php?topic=41860 ? ? ? DIY traffo Test Build Uli
http://www.elab.ph/index.php?topic=33717  I2c / spi programmer
http://www.elab.ph/index.php?topic=37150.0 Lcr esr makikigulo rin ba kayo ??? Test Build
http://www.elab.ph/index.php?topic=29963.0 Esr collection na malamig
http://www.elab.ph/index.php?topic=25854.0 Basic C++ Programming Tutorials by Prof Asimo
We only live once,treasure those we love, make friends not enemies and keep our family closer. And we will be at peace.
FISH

Offline bravokilo

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Re: Looking for an isolation transformer
« Reply #7 on: December 04, 2019, 11:31:34 PM »
???, hi,magkano kaya 2000 watts?Gusto lagyan yun water heater sa banyo.

Offline congressman

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Re: Looking for an isolation transformer
« Reply #8 on: December 05, 2019, 11:54:10 PM »
natry ko jan sa shower heater ko yung microwave transformer. apat na secondary coil. primary at secondary ginawa ko baligtaran pwede. dalawang e core.magkasaklob.
imbento ko umubra. na try ko din sa electric stove.
Peace!

Offline >>>^żżż^<<<

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Re: Looking for an isolation transformer
« Reply #9 on: December 06, 2019, 08:00:16 PM »
???, hi,magkano kaya 2000 watts?Gusto lagyan yun water heater sa banyo.

mga 1.6k sa core tapos 2.5k sa copper plus accessories transformer pa lang. Kung commercial baka 10k -15k na iyan. Di ako sure
http://www.elab.ph/index.php?topic=52236.0 TF?
http://www.elab.ph/index.php?topic=41860 ? ? ? DIY traffo Test Build Uli
http://www.elab.ph/index.php?topic=33717  I2c / spi programmer
http://www.elab.ph/index.php?topic=37150.0 Lcr esr makikigulo rin ba kayo ??? Test Build
http://www.elab.ph/index.php?topic=29963.0 Esr collection na malamig
http://www.elab.ph/index.php?topic=25854.0 Basic C++ Programming Tutorials by Prof Asimo
We only live once,treasure those we love, make friends not enemies and keep our family closer. And we will be at peace.
FISH