200vdc 1A supply, adjustable 180-220vdc

[Herman Botha]

Hi Hevans

I take it that is H Evans?

That was indeed a nice trip down memory lane. Took me right back to the 5Y3's and 6v6GT's of many moons ago. And to the thrill of my first very well working amp of round about 1962. Shortly before that, silicon was something you made glass with! What a miracle when the selenium bridge rectifiers hit the market. And the nice smell of old cabbage when one of those emitted smoke rather than DC. And sometimes the accompanying mini-landmine of a fat electrolytic exploding.

I would not now use valves any more, but those were the days.

I feel sure that the LM317HV approach will do it, and a few of those could drive everything. The situation is that my son owns an high end audio shop in George, South Africa and he sells only expensive stuff. He uses for himself mostly things like Pass Labs, T&A from Germany and lately the nice valve amps from the Czech Republic made by Kr Audio. The latter makes tubes (BIG bottles) by hand and are quite exceptional. You can see his site a here:
Tweak.co.za. I actually did the site for him. Now, he also started a high end Juice by day and cocktails by night cocktail bar, and this is where all the led work gets done.

The Home automation system running his shop, the cocktail bar and all is by Vantage Controls from the States, and in the end boils down to relay modules activating relays by pulse, in the order of 36vdc and below.

Everything is up and running and the "grand opening" will be soon. Why we are still onto the leds issue is simply because we could not yet get them to behave just as we would like them to, in terms of colour (or color) your end of the world. Transitions from one scene to another was also not quite as we would like it.

We will now take the approach of separate PSU's based on the series regulators you guys suggested. I have often used the low voltage types in many applications.

Thanks again for you helpful inputs. You seem to be 1944 vintage, myself 1948.

Herman

 

[hevans1944]

Yep, H. Evans it is. Born Sunday, June 25, 1944 at high-noon local time in Welch WVA. More information available if you Google my amateur radio call sign: AC8NS.

 

[Herman Botha]

I am no longer active, used to be ZR6HBA and was member of and even chaired the Pretoria Amateur Radio Club for a year or two. Never did the CW exam, but had morse down pat. Not fast, about 15-20wpm.
Just google http://www.parc.org.za. Even built a morse encoder/decoder about 16 years ago.. Still playing around on 2 meters now and then. Actually spent my life in law as public prosecutor Asst DA your end. and later and for 22 years as legal guy for the National Parks Board of SA, now SANPARKS. Electronics was a life long hobby. Built all imaginable gadgets, least of all not all the DJ'ing equipment when my sons were that age. Amps, mixing consoles, speakers, sound to light, a little bit of laser, etc etc.

This is becoming a social chat. Someone, may be the moderators, will object. Look at dollhouse.co.za, click english and contact, and there you can find me. I made these, for a shop my wife had, but stopped now and only make on demand. Woodwork was the other life long hobby and my CNC router machine is still a joy.

Herman

 

[(*steve*)]

This is becoming a social chat. Someone, may be the moderators, will object

We're pretty social around here. Anyway, its your thread -- I'd be more concerned if some other person was still hanging out for an answer. If it gets really social, we can easily split it off into another thread.

 

[Herman Botha]

I

f it gets really social, we can easily split it off into another thread.

Thanks Steve, being the newby around I do not want to break the rules or style!

 

[hevans1944]

I

Thanks Steve, being the newby around I do not want to break the rules or style!

Well, as long as you don't adopt my long-winded style I think we'll be okay. And there is the Off-Topic Members Lounge where almost anything is okay.

But, back on-topic: If I can clear the junk off my electronics workbench in the basement and find some "spare time" I will breadboard a circuit using an op-amp to drive the ADJ terminal of an LM318 I bought recently for another project.

I was helping a fellow in England design the control for the hydraulics on his front-end loader. He was going to use three joysticks to control the hydraulic solenoid control valves, but may have decided to just wire the solenoids to toggle switches. This project is more than a year old, maybe closer to two years... I will have to go back and review my correspondence with him. It involved using op-amps to "read" the joystick potentiometers, convert their bipolar outputs into direction control signals for each of two hydraulic control valves on each movement axis, and then using the LM318 as sort of a power amplifier to drive each valve, a relay being used to select which valve according to joystick position. I always like to breadboard before building the real deal, but didn't have the capability to do that.

I might get into the same difficulty trying to help with your project, but I will give it a try. Probably start out with less voltage than 240 V just to test "proof of concept" instead of rushing forward to maximum smoke. Or "press to MECO" as the astronauts riding the candles from Cape Canaveral put it. Press, indeed, as if they had any control of the outcome. I'll go slow and use a Variac while monitoring voltages, currents, and heat. I still need to investigate how to prevent disaster if the output is shorted to ground. That may not even be possible, given the voltages and currents involved, but I will look into it after getting the main thing to work.

 

[Herman Botha]

But, back on-topic: If I can clear the junk off my electronics workbench in the basement and find some "spare time" I will breadboard a circuit using an op-amp to drive the ADJ terminal of an LM318 I bought recently for another project.

In this case the business must be fully operational at or before the end of the month. Hence, we will be using what we have now. That is. a couple of supplies made up by using toroidals and bridge rectifiers and a nice cap each. We came close to the voltages by having toroidals made with secondaries at different levels so that the outputs are close to what we need. It does not give us the fine tuning for exact colors, but we came close. This project may be required once the place is up and running and "tweaking" is needed. My son, owner of the business, is a serious perfectionist and things must be just right. I would never expect though that you go through the trouble of making something to solve this. In the end we might be able to simply use potential dividing, as what we have to drop will be relatively low numbers, and we should not be building heaters.

There are a few other things that you could help with, in stead. I'll get around to those and let you know. You will find those more interesting as well. For instance, with the very high end audio, and grid power being not all too reliable these days, we have outages and on/of/on/off situations when power is switched back on. Some surges and high spikes too, in many cases. Bad, bad news for the high end stuff, We have worked quite a bit towards a unit that will monitor grid voltages, switch off in cases of over or under voltages or total loss of supply, and switch the equipment back on sequentially once power is restored, but only after a predetermined delay and voltages found to be stable at the correct levels. It could also be handy for things like fridges, that do not particularly favor intermittent supplies. That is a project that has gone on a couple of years already!

These days, I install domestic alarm systems and CCTV, obviously using IP stuff and giving people remote access to their CCTV systems when away from home. That takes up quite a bit of my time, and then also: " I aint what i used to be" 16 hour workdays are becoming a bit tough.

Enough rambling Have a good day!

 

[hevans1944]

Well, if you need it right now, I can't be of much help... I have Hamvention® to attend this weekend, grass to cut, junk to sort out and throw away before moving to Florida... Yada, yada, yada.

But I am curious to know how you control the intensity of the LED colors using just relays. Do the relay contacts select different voltage windings, or winding taps, on your toroid transformers to determine the rectified output voltage to your LED strips? Maybe relay contacts select different divider resistors in your voltage regulator? Insert power-dissipating resistors in series with the LED strips? Please elucidate.

A device that monitors power-line outages needs to distinguish between surges and sags, which are common even on the best distribution systems. They are typically caused either by lightning strikes or sudden changes in grid load, like factories adding or shedding massive amount of power in the morning during start-up and in the evening during shut-down. A good grid distribution system will monitor and prepare for and anticipate these events, but sags and surges still happen. Can't do much about it without going to a lot of expense, but usually sags and surges are excessive, they can be ignored or taken into account during power supply design. Things with motors are a whole different story. Motors especially don't like large voltage sags, overheating considerably.

A little microprocessor could be programmed to monitor the power line and disconnect power under the appropriate conditions, running on a back-up battery if line power truly vanishes for multiple cycles. As you mentioned, the program would restore power after good line power is detected for several hundred cycles, perhaps also counting how many times these power fail/power restore events occur in a specified interval, aborting the power-off/power-on sequence if too many interruptions occur over a specified period of time. Obviously you don't want it to continuously cycle power off and on for things like fridges that have compressors. So the choice of when to turn off and when to turn back on may be specific to what is being controlled. Maybe a μP per device.

It would also be nice to have a choice of automatic fault clearance and restoration of power, or manual reset to clear faults after power has been observed by a human to have been restored. I am sometimes fooled by that though, especially when some idiot downs a power line pole in the neighborhood. Power goes out. Some minutes later power comes back on. Still later (as the line crews do their thing) power goes out again. At this point I quit trying to get all the computers in the house to re-boot and either go to bed (if at night) or get in my car and drive around to see what's going on. A few years ago we had fallen high-tension lines burning trees in the neighborhood. Pretty spectacular to watch. With manual reset, you can squarely place the blame for refrigerator compressor burn-out on the person who reset the system.

The high-priced alternative of course is a back-up UPS that powers everything all the time. In case of an extended power failure the UPS needs to fire up a diesel motor-generator set before the UPS batteries are depleted and automatically transfer the UPS power source from mains to MG set. Hospitals (the better ones) use this arrangement, but I am guessing it is way beyond the means available to a cocktail/juice bar. Here in the States you will find Preppers who love this idea. Some actually implement it, probably placing the MG set and its fuel and the UPS and its lead-acid batteries in the same underground vault used to store their ammo, weapons, food, and potable water supply for an extended siege after civilization breaks down. I am not a member of that group, so if the SHTF I guess I will die along with everyone else who is not "prepared." In the meantime, I am sure we can work something out that won't break the bank and still provide a modicum of safety for all that high-end audio/visual equipment. Let us know your requirements.

Hop

 

[Herman Botha]

Hi again

My day has started, it is 8 am and the chill is beginning to bite a bit. Lots to do today. I will get back about this topic, later today. It being 02:00 your end, you will probably only receive this in a few hours from now, unless you also have the habit of getting up in the middle of the night. I am not a good sleeper.

You have obviously hit the nail on the head with many of your comments. We have considered pics, but I cannot say that I trust them implicitly. I will send some more info.

Herman

 

[hevans1944]

I love PICs. Reliability is not an issue with them AFAIK. Going to bed now.

 

[Herman Botha]

The leds are up and running now. Not quite the way we like, but OK for the grand opening. Thus, the power supply is on hold for a bit.

I know very little about pics, and unknown is untrusted, probably. I do not even know how to really rectify this by getting started and learning more.

Herman