The transformerless supply question

[Ian Rogers]

Do not bring the forum down to this level!!! Keep it on topic... Verbal abuse will not be tolerated...

 

[tvtech]

Yes sir, I have lots to learn - and loving every minute of it!
I don't see a problem troubleshooting the TLPSU. Plugged into my Isolation Transformer would give it isolation.

If you follow the whole X2 cap thing.....even with an Isolation Transformer you can still get shocked.

tvtech

 

[KeepItSimpleStupid]

Oh, I did recently invest in an isolation amplifier. I haven't powered it up yet.

 

[rc3po]

Hi

Any Transformer that is going to fit into an enclosure (see Avatar) that is :L=100mm, W=60mm,H=30mm will have to be SMPS in order for there to be any space left for the battery, electronics and so on. As a TV tech that deals with SMPS repairs every day of my working life......I wanted to stay away from any SMPS type circuitry.

I needed extreme electrical reliability with the circuitry having to handle periodic Mains surges of anything up to 300VAC + that kills SMPS's stone dead. (Think small generators on farms that have been known to "run away" and blow up everything until they can be switched off, or our notoriously bad electricity supply in rural areas and townships/squatter camps here that causes anything SMPS to eventually fail or blow up). I needed something that could handle this kind of electrical abuse without any drama.

So in 2009 I started investigating the X2 capacitor to see how it would handle the job as a Mains current limiter. I needed 120mA constant current at a regulated 10VDC which would take care of both charging the battery and powering the LED's.

One VERY important lesson I learned whilst using a cap in this way is NEVER LOOSE THE LOAD. If for some or other reason this happens you are going to have a lot of drama on your plate. The supply voltage from the cap will go sky high and destroy your project and possibly shock you too if you are poking your fingers around inside when it happens. (This happened in the development phase where I was using breadboard...and a wire going to the head (load) came loose. The Electrolytic smoothing cap exploded and the Regulator went to heaven etc). I never got physically shocked but I was still shocked at how quickly all blew up in front of me.

So, learning from this, I decided to put everything on a PCB. The only way I could accommodate everything safely was the board had to be double sided.

So, I designed the first double sided board always keeping in mind creepage distances etc. To cut a long story short, everything worked as expected with the first prototype boards. No nasty surprises.

But as any of you know that has designed or built anything from scratch.....fine tuning is very important.

So the board went through two revisions. Little things here and little things there. One of the parts built into the last revision is a 5W Zener that clamps the output from the Bridge and in so doing aids the series Regulator in staying a bit cooler when overload times come.

So, on the 9th and 10th of June last year 2013, with this little guy in it's ABS casing and 3mm Polycarbonate lens and a small hole drilled to accommodate the heat sensor onto the Regulator and sealed from prying fingers....it was put to the test.

I initially wanted to see if it could handle 400VAC for 30 seconds. I would of been happy with that. So the test began at 400VAC...

30 Seconds came and 30 Seconds went. No problem. I said to my friend "lets try 1 Minute and see what happens". No problem.
Lets try 2 Minutes. No problem.

Ended up a in a 5 Minute run at 400VAC. All good.

So being the kind of person I am and wanting to prove that all my hard work in this was worth the while I said " we are going to do another run @ 400VAC for 5 Minutes". Same result. No problems.

And then the final run @ 400VAC 5 Minutes later while this baby is still recovering. Same result. All OK. This is my personal unit that is exactly the same as the other testing units out there....and still to this day has shown no signs of the abuse I put it through last year in June.

So lets look at stuff here:

1. I agree that Transformerless power supplies can be dangerous to people that do not understand them.
2. I agree that they are bad news for people that are merely hobbyists playing around with a potential shock hazard.
3. I agree that they are bad news for people that won't listen. And then leave in a huff.

BUT:

They are excellent for certain applications ( like mine). Will I ever release a kit that people can put together on their own = NO
Will I ever show the details of my design on a Forum or the NET = NO.
Will I encourage Newbies to try this on their own = NO.
Will I release a a fully built, tested and sealed unit....already done. I have orders. And I am not hasty for money. People that have this little Guy for testing swear by it. They find uses I never dreamed of.

All I am saying is that Transformerless power supplies are out there. Many of them. And they are crazy over the top reliable if built the correct way.

And thanks to ETO and Mods and all to get this off my chest forever

See this link here: https://www.electro-tech-online.com...he-public-domain-at-last.136196/#post-1146578

Regards
tvtech

Umm...., isn't that what "surge protectors" are for? TV Tech, I'm not trying to be a troll, I just really don't understand your position on this topic... I have 2 surge protectors everything is plugged into in case of voltage spikes.
A few months ago when we had a thunderstorm come through, a voltage spike from a lightening strike popped the breaker in one of my surge protectors. I went ahead and turned the other one off and disconnected them from the wall until the storm passed. Then I plugged them back in, and all was well.
Now, if this comment is unacceptable, then I give up!

 

[tvtech]

Surge protectors are not able to handle frequent surges. They themselves fail and leave the circuit they are supposed to protect....well unprotected.

If you are trying to design something properly...rather rely on circuitry that can handle overload situations repeatedly..instead of designs that protect weak circuits.

Hopefully this makes sense.

tvtech

 

[rc3po]

If you follow the whole X2 cap thing.....even with an Isolation Transformer you can still get shocked.

tvtech

Yes, but I won't be connected to mains ground...

 

[tvtech]

Yes, but I won't be connected to mains ground...

Correct but you you can still get belted if the load is lost on the supply you are trying to fix...

Whilst I feel sorry for you....I am around 51 Years now...also feel totally battered.

Thing is a Forum is a place to discuss things and respect the powers that be. Do not disrespect Moderation or some of the amazing people that take on that very hard task. Maybe you have to learn still. I don't know.

I have given you more dislikes.....if you can deal with that then we can talk.

Sit back and reason

Think about stuff. I really don't dislike you nor does anyone here in spite of you pushing Moderation to the limit. Any other Forum out there would have probably thrown you away. Luckily ETO has Moderators that don't take things up personally.

Referring to this thread: https://www.electro-tech-online.com/threads/performance-electric-cars.140421/page-6

Stay well,
tvtech

 

[rc3po]

Correct but you you can still get belted if the load is lost on the supply you are trying to fix...

Whilst I feel sorry for you....I am around 51 Years now...also feel totally battered.

Thing is a Forum is a place to discuss things and respect the powers that be. Do not disrespect Moderation or some of the amazing people that take on that very hard task. Maybe you have to learn still. I don't know.

I have given you more dislikes.....if you can deal with that then we can talk.

Sit back and reason

Think about stuff. I really don't dislike you nor does anyone here in spite of you pushing Moderation to the limit. Any other Forum out there would have probably thrown you away. Luckily ETO has Moderators that don't take things up personally.

Stay well,
tvtech

Well he was baiting me, which a moderator shouldn't do. I did get a little carried away though and I will apologize to him.
Back to the subject, yes it's true, we can get shocked with an isolation transformer. Mine is rated at 5Amps. That's a lot better than the Amps mains ground could give me.
Hey I don't want to argue, Ok?

 

[tvtech]

Lovely stuff!!

We can all get along nicely together if we simply try.

Hey, I am too old to argue too

Regards,
tvtech

 

[MrAl]

Hi,

Back on topic...

One of the first things they teach in electronics classes is how to measure voltage. They always say "keep one hand in your pocket" or something like that.

When it comes to power supplies there are many dangers. Capacitors blow up, transistors blow up and spew metal in various directions. The person entering ths field as a hobby for the first time has no idea what the dangers are, so we simply must tell them. This is especially true with voltages above maybe 15 volts or so.

We cant stop people from doing this as a hobby, and when they see an offline power supply they naturally get curious because it does not need a transformer, which is sometimes hard for them to get. So the best thing to do is tell them about the dangers and make it very clear, and then proceed with some circuit theory.

It wont help to avoid the subject...that could be worse because then they might experiment on their own without any guidance at all.

Any site that wants to talk about hobbies that might be dangerous should just post a disclaimer that appears when the member first signs up and possibly a sticky thread too.

 

[ronv]

Hi,

Back on topic...

One of the first things they teach in electronics classes is how to measure voltage. They always say "keep one hand in your pocket" or something like that.

Good advice that I always tried to follow. That and no ties around machinery, and no rings when working with high current.

When I was a kid I was into ham radio. My transmitter had a 3000 volt 500 ma power supply. One day the knuckle of my right hand got to close to the plate connection of the output tube. I know this because when my eyes opened I found myself in my comfortable chair with my finger and my right knee still smoking. Took forever to heal. Glad it wasn't both hands!

 

[tvtech]

Wrong thread. Post deleted.

 

[large_ghostman]

TVtech

In the recently revised rules for the forum, we have the following statement on safety:

***************************************************************************************************************************************
Safety
Safety is important to everyone.
Ultimately you and you alone are responsible for your own safety regarding any circuit, device, or system you are working on.
Keep in mind that some members here may be as highly skilled and experienced as others are incompetent and careless.
That means that no one but you, the end user, can see and accordingly judge the potential dangers that others' advice or suggestions may hold for you, based on your present skill sets and knowledge of what you are attempting to do.
If you are not sure if something someone says is safe or legal, ask follow-up questions and do more research before attempting it. It is ultimately your responsibility to determine whether or not a solution is safe and legal. Use the information you get here at your own risk and to the best of your own judgment.
***************************************************************************************************************************************

In my opinion that covers the "liability issues".
As you comment, there is at least one popular electronics forum which forbids discussion of automotive topics and transformerless power supplies, that is their perogative to do so.
Is it helpfull? Probably not.

And yet the same forum is currently let a certain recently banned member from here, openly discuss what are clearly avionic circuits, and despite them being told and indeed concluding the same themselves, are turning a blind eye and trying to help the person fault find them!!!


Funny old world!
And people still dont understand why I find it so hard to grasp certain rules and procedures! I am a logical thinker and simplistic person, I live in a complex and contradicting world. No wonder I struggle at times to fit in

 

[large_ghostman]

I like old radio's and TV's, I dont have many (6 or 7), but I have tinkered with them all and restored to working, except one that is.
Some have the live antenna socket at the back, some of the radio's have live metal box's inside the wooden case. At first I thought this was mad and I am glad this isnt done anymore, then I started to meet people like said avionics tech above.
This got me thinking... Maybe today there is more stupid people around because we have lowered the chances for natural selection

 

[tvtech]

I like old radio's and TV's, I dont have many (6 or 7), but I have tinkered with them all and restored to working, except one that is.
Some have the live antenna socket at the back, some of the radio's have live metal box's inside the wooden case. At first I thought this was mad and I am glad this isnt done anymore, then I started to meet people like said avionics tech above.
This got me thinking... Maybe today there is more stupid people around because we have lowered the chances for natural selection

LOL

Its OK LG. I was on "that other Forum" for a while and lost interest. Huge double standards.

It's not OK to discuss modifying cars....but perfectly OK to discuss repairing Aircraft electronics

Crazy.

Regards,
tvtech

 

[JimB]

LG wrote:

And yet the same forum is currently let a certain recently banned member from here, openly discuss what are clearly avionic circuits, and despite them being told and indeed concluding the same themselves, are turning a blind eye and trying to help the person fault find them!!!
Funny old world!

It is indeed a funny old world.
I doubt that the "recently banned member" is actually working on equipment which will be installed into an aircraft which will fly.
However, it could of course be that he is a completely competent guy who does work on such equipment in a safe and satisfactory manner, but who gets his jollies from winding up other competent guys with his charade of incompetence.

I considered it a possibility that he is actually a "charity case".
He works as a go-fer in a small workshop which actually does repair avionics equipment, and in his dowtime they let him play with scrap equipment in a corner of the workshop. As an extension of this playing he comes on to the internet forums asking questions which the workshop guys cannot be bothered to answer, or more likely he just cannot grasp.

And people still dont understand why I find it so hard to grasp certain rules and procedures! I am a logical thinker and simplistic person, I live in a complex and contradicting world. No wonder I struggle at times to fit in.

Don't worry, it can only get worse as you go through life and gain experience.

A couple of examples from my career.

Many years ago, while working as an Instrument Technician I repaired a temperature controller for a furnace. A simple thing, a thermocouple drove a moving coil meter, a flag on the meter pointer intrupted a lightbeam and a photocell operated a relay to turn off the heater.
The faulty controller was in the workshop, I fixed it, and it was neededback on the furnace asap. So I took it to the furnace.
Now, I could do whatever I liked to that controller while it is in the workshop, but I could not connect it back up to the furnace, oh no, that is an electricians job.
So, along comes the electrician. He only has one hand! He is a mono-dexter!
So I, stand there, holding up the controller, while he deftly inserts the wires into the terminal block and tightens the screws, all done one handed.


Different time, different place, different company.
We had to set up a test rig to simulate a system that was mis-behaving.
Part of this test rig was a number of PCs running our own proprietary software.
At the time we were at best starved of resources (the PCs), so instead of buying a bunch of them (about 5) and making them available for general use in the office when the test was over, you could not imagine the solution which the management dreamed up...

... As it was the Houston (Texas) office who wanted the test done, they would supply the PCs.
As it happened, they had just upgraded their desktop PCs from 386s to 486s (yes it was that long ago), so they boxed up five of the old 386 PCs and sent them to the UK for us to use for the test.
It gets better...
So that we in the UK did not have to pay tax, VAT etc on these PCs, when the test was over, they were put back into the crate and sent back to the USA.

So whether some apparent half wit on some internet site is or is not trying to fix avionics, and what any random internet site considers should not be discussed, be it automotive electronics, avionics or nuclear reactor control systems, is just down in the noise floor of life.

Try not to worry about it.

JimB

An after thought.
Good persons who strive to help the "recently banned member" deserve a place in heaven. (good grief! did I just say that?).
For me, I have posted to help out that person, but never again.
I would not waste my time and effort on such a fools errand.

 

[MrAl]

Hi,

I just thought of something that happened to me regarding safety.

Way way back before transistors were popular, we only had tube radios and amplifiers. My interest in electronics back then was not much different than today so i naturally wondered about how they worked. One big difference though is that they used HUGE dc buss voltages. I mean 400 or 500vdc power rails, not plus and minus 15 volts. Needless to say one day in the basement i accidentally touched a 400vdc supply rail (dont remember exactly what i was doing at the time other than just playing around with a tube amplifier). I think it knocked me out for a few seconds, but obviously im still around to tell about it.

The real point of this post though is that way back then we had no forums, we only had electronic magazines (and i dont think i subscribed to one yet at that time), so there was no one to really ask about this stuff. I could have been killed that day, even though there were no forums, so that tells me that forums cant be a cause of danger. If i had a forum at the time i might have been able to ask about that and im sure members would have came back with a thousand cautions about the danger of the 400vdc power rail, and that might have saved me from a very very nasty shock. I got a bad shock and that's just because of my human nature, and that's the way people are.

I can only conclude that forums can help people with regard to safety because people tend to do risky and/or dumb things sometimes mostly because they are not aware of the dangers involved. Forums help people become aware of the dangers and i think that's important.

 

[large_ghostman]

LG wrote:

It is indeed a funny old world.
I doubt that the "recently banned member" is actually working on equipment which will be installed into an aircraft which will fly.
However, it could of course be that he is a completely competent guy who does work on such equipment in a safe and satisfactory manner, but who gets his jollies from winding up other competent guys with his charade of incompetence.

I considered it a possibility that he is actually a "charity case".
He works as a go-fer in a small workshop which actually does repair avionics equipment, and in his dowtime they let him play with scrap equipment in a corner of the workshop. As an extension of this playing he comes on to the internet forums asking questions which the workshop guys cannot be bothered to answer, or more likely he just cannot grasp.



Don't worry, it can only get worse as you go through life and gain experience.

A couple of examples from my career.

Many years ago, while working as an Instrument Technician I repaired a temperature controller for a furnace. A simple thing, a thermocouple drove a moving coil meter, a flag on the meter pointer intrupted a lightbeam and a photocell operated a relay to turn off the heater.
The faulty controller was in the workshop, I fixed it, and it was neededback on the furnace asap. So I took it to the furnace.
Now, I could do whatever I liked to that controller while it is in the workshop, but I could not connect it back up to the furnace, oh no, that is an electricians job.
So, along comes the electrician. He only has one hand! He is a mono-dexter!
So I, stand there, holding up the controller, while he deftly inserts the wires into the terminal block and tightens the screws, all done one handed.


Different time, different place, different company.
We had to set up a test rig to simulate a system that was mis-behaving.
Part of this test rig was a number of PCs running our own proprietary software.
At the time we were at best starved of resources (the PCs), so instead of buying a bunch of them (about 5) and making them available for general use in the office when the test was over, you could not imagine the solution which the management dreamed up...

... As it was the Houston (Texas) office who wanted the test done, they would supply the PCs.
As it happened, they had just upgraded their desktop PCs from 386s to 486s (yes it was that long ago), so they boxed up five of the old 386 PCs and sent them to the UK for us to use for the test.
It gets better...
So that we in the UK did not have to pay tax, VAT etc on these PCs, when the test was over, they were put back into the crate and sent back to the USA.

So whether some apparent half wit on some internet site is or is not trying to fix avionics, and what any random internet site considers should not be discussed, be it automotive electronics, avionics or nuclear reactor control systems, is just down in the noise floor of life.

Try not to worry about it.

JimB

An after thought.
Good persons who strive to help the "recently banned member" deserve a place in heaven. (good grief! did I just say that?).
For me, I have posted to help out that person, but never again.
I would not waste my time and effort on such a fools errand.

I did think about the charity case idea, for a while it had merit. Then I thought but in that scenario it would mean they had to let him loose with a broom! So I did a search on the net and nowhere can I find question's like the following

1) I have a broom with 600 bristle's and the guy next to me has 500, WHY, why would you need 600 bristles and can you give me 100 examples of where 600 bristle on my broom is better than 500.

2) In the manual for my broom it says it has an attachment point for a duster, can I use the duster instead of the broom when I sweep up? Should I use the 500 bristles or the 600 bristles head? Why do they have dusters on brooms? when would you use the duster instead on the broom? Can you give me 100 examples of when a duster is better than a broom for sweeping

3) The broom tech next to me say's when sweeping a tiled floor you should always sweep from the back to the front, my manager say's to sweep from the front to the back! How do you sweep on a tiled floor? why do you do it that way?
If I use the duster on the broom should i sweep back to front or front to back? The manual dosnt say anything except sweep the foofing floor, Can you give me 100 examples of when you personally would sweep back to front and front to back. On a tiled floor do you use front to back or back to front??? Have you tried this with the duster?

4) We also have a mop, why should I use the broom instead of the mop? Whats the mop for? what advantage does the mop have over the broom when sweeping the floor? I tried sweeping with the mop and it didnt work, why? The tech next to me always uses the mop and it works for him, why didnt it work for me? Why dosnt the mop have a fitting for a duster?


So in the absence of these question's I decided he didnt work somewhere willing to let him loose with a broom. In the end I decided he was a idiot savant with the savant bit missing.

As for brain dead action's


The council who run my School make a huge thing about all the Schools having a healthy eating policy,on the web site it goes to great lengths to explain chips and burgers are outlawed in Schools and only healthy food is offered.
Then the same council sells licenses to 4 burger van type set ups so they can park OUTSIDE my SCHOOL GATES at lunch time to sell burgers and chips to the kids!

 

[large_ghostman]

I think I covered Mr Al's point in post 34 lol

 

[4pyros]

I considered it a possibility that he is actually a "charity case".
He works as a go-fer in a small workshop which actually does repair avionics equipment, and in his dowtime they let him play with scrap equipment in a corner of the workshop. As an extension of this playing he comes on to the internet forums asking questions which the workshop guys cannot be bothered to answer, or more likely he just cannot grasp.

That would explain alot. Is he still over there? Sometimes I would like to read his stuff for a good chuckle and to remind myself how far I have come.