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Lambda
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Quote: Originally posted by quicksilver  |
... I did finally find a scrapyard with electronics and was overjoyed to find that I now can buy some things without working with eBay. And you all
are absolutely correct as the above ss relays did sell fo about $9USA. The best thing is to go when the proprietor is at lunch as I got another
powerfully switchable (this time a company called QSI that was bought out by Lamda) that pumped 150A. ... |
@quicksilver,
I am pleased to read about you successes at the Scrapyard ! 
Working with eBay can be a Pain in the Rear, for not only are You dependent on the Reliability of the
Dealer, but the Guys working for the Postal Services in My Country Holland, Steal like Raves !! And the Postal Services refuse to refund
Stolen Goods, for they don't employ Thieves. I have lost a substantial $ and € amount of Goods in this way 
And when dealing with the Scrapyard, by leaving the Proprietor out of the Equation, indeed can lead to a substantial reduction in Price. A
Crate of Beer also works pretty well too 
Taking a Beautiful Girlfriend along will also Impress them !
A LAMBDA Power Supply is indeed a Top Notch Modern Marvel, ... how could anyone
expect anything less ? And where have I heard that Wonderful Name before ?
More Info on Power Supplies and Triacs:
DC Power Supply Handbook
Introduction:
This handbook is designed to aid that understanding by providing complete information on the operation, performance, and connection of regulated power
supplies. The handbook is divided into six main sections: Definitions, Principles of Operation, AC and Load Connections, Remote Programming, Output
Voltage and Current Ratings, and Performance Measurements. Each section contains answers to many of the questions commonly asked by users, like:
- What is meant by auto-parallel operation?
- What are the advantages and disadvantages of switching regulated supplies?
- When should remote sensing at the load be used?
- How can ground loops in multiple loads be avoided?
- What factors affect programming speed?
- What are the techniques for measuring power supply performance?
In summary, this is a book written not for the theorist, but for the user attempting to solve both traditional and unusual application problems with
regulated power supplies.
DC Power Supply Handbook (Agilent Technologies AN 90B - 1978, Rev. 2000) 126s.pdf
Attachment: DC Power Supply Handbook (Agilent Technologies AN 90B - 1978, Rev. 2000) 126s.pdf (1.1MB)
This file has been downloaded 731 times
Triac Control by Pulse Transformer
Introduction:
Among the many ways to drive a triac the pulse transformer is one of the easiest. By applying some simple rules it can be used to design an efficient
triac triggering circuit without reduction of the commutation capability of the triac.
Why use a Pulse Transformer?
The use of pulse transformers in triac triggering circuits offers many advantages:
- Galvanic insulation between the power and gate drive circuit (a few kV).
- Gate drive circuit with a few components.
- Choice of the gate current polarity (triggering in the 2nd and 3rd quadrants for SNUBBERLESS triacs).
- Optimization of gate signal (single pulse or train of pulses).
- Possibility to drive several triacs with only one drive circuit
Triac Control by Pulse Transformer (STMicroelectronics AN436 - Rev.D2A-3575 - April 2004) 9s.pdf
Attachment: Triac Control by Pulse Transformer (STMicroelectronics AN436 - Rev.D2A-3575 - April 2004) 9s.pdf (66kB)
This file has been downloaded 575 times
Thyristor Theory and Design Considerations Handbook
Thyristor Theory and Design Considerations Handbook (ON Semiconductor - HBD855-D - Rev.1 - November 2006) 240s.pdf
iFile.it Download Link (2.48 MB):
http://ifile.it/zmie1la
No Password Required !
Pink Floyd - Money ("Pulse" Tour):
http://www.youtube.com/watch?v=6RqwLWR42nE&feature=relat...
Enjoy !
Lambda
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quicksilver
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Thanks for posting those!
The only place I found pulse transformers that were sold a a decent price was:
HTTP://amazing1.com
I DID find a Neon sign shop that was going out of business awhile back when I was making Tesla coils and got about 300lbs of HV transformers. Here we
have a "club" of people that experiment with high voltage stuff but it's in the city and I have to drive about an hour to get there. but many of these
guys have their doctorate in electronic engineering and have made stuff I can only dream of putting together.
I also trip into this forum, which has a wealth of info.
http://4hv.org/news.php
[Edited on 2-3-2010 by quicksilver]
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densest
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The amazing1 transformers are not what you want. You want "gate drive" or "SCR/thyristor trigger" transformers with a turns ratio of 1:1. "Photoflash"
trigger transformers have a high turns ratio and deliver low current at very high voltage.
This is one case where it is usually cheaper, easier, and safer to get new parts from a distributor. You can get guaranteed 1500VRMS isolation for $4
or less and guaranteed characteristics.
For large, heavy, relatively low tech items like big iron transformers surplus is definitely the way to go, but this isn't the part to go "unknown
specs" on. If you don't get it right you will get random flickery outputs and/or shorted driver circuitry, and for these pulse transformers new parts
are cheaper than any surplus supplier I've found!
The biggest problem with buying these from anyone is that they're rarely classified correctly in online shopping sites. You almost have to start at a
manufacturer (google gate OR scr OR thyristor transformers) and find their distributors.
One part that looks good is Pulse Engineering P0584NL. It is $4 each from www.mouser.com. Murata has a line, etc. Newark/Farnell also stocks some pulse/gate drive transformers but their search engine is pretty useless.
If anyone wants some help picking the right transformer send a PM.
I know people have been trashing Mouser as a supplier. For small items like resistors, capacitors, transistors, etc. they are often
the cheapest distributor - I've bought 100s of parts there after comparison shopping. They will ship any way you choose and are quick - usually 1 day
from order to shipping. They also gave me a credit account 
You can wind your own if you don't care about safety or you're willing to put 2 layers of transformer insulating tape and 10mm spacings between wires,
etc... a small toroid (1cm) and 2 x 10 turns of #30 wire should do it. Don't use RFI/interference suppressing material because that would kill the
pulse! There's an article on how to design one http://powerelectronics.com/passive_components_packaging_int... for the masochistic.
For a 25A SCR a pulse 3 microseconds long at 5V should trigger it reliably as long as the SCR is above 0C. It might take 4-6us if it's -40C. A huge
(300A) SCR will take 7V for 30microseconds.
Using an excessively long pulse or high drive voltage will not help. The transformer will "saturate" i.e. cannot hold any more energy and suddenly
look like a short circuit to the driving electronics and its output will drop to zero. Pulse transformers are rated in "volt-seconds" or
"volt-microseconds": the voltage applied times the length of the pulse. Small transformers cost about $0.10 per volt-microsecond, so a $3 or $4 unit
should be plenty if the drive circuit provides a short (2-4 microsecond) , high current (100-200mA) pulse at 5V.
[Edited on 2-3-2010 by densest]
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quicksilver
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NO, I know what you're saying. Mouser IS fine for some stuff. I just wouldn't buy their variacs :-)
Thanks for the tip!
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watson.fawkes
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| Quote: Originally posted by densest | | You can wind your own if you don't care about safety or you're willing to put 2 layers of transformer insulating tape and 10mm spacings between wires,
etc... a small toroid (1cm) and 2 x 10 turns of #30 wire should do it. Don't use RFI/interference suppressing material because that would kill the
pulse! There's an article on how to design one http://powerelectronics.com/passive_components_packaging_int... for the masochistic. |
Masochistic? That
article's well written. The comment on bifilar/trifilar winding is particularly useful, as it would tend to lower the maximum fields in the
core somewhat.
I'm confused about what you said, though. How do you get 10mm spacing on a 10mm (1cm) toroid? I suspect typo. Can't you get adequate isolation between
primary and secondary with a high-quality insulation on the wires? If you need 10 kV isolation, I suppose it gets easier to use an air gap, but
where's the trade-off point?
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densest
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@watson.fawkes - yes, I confused "safety" with "basic" insulation requirements: I think 1.6mm is enough for 1500VRMS - reasonably safe if the
triac/SCRs are directly connected to the mains.
Bifilar/trifilar windings are really useful in many cases. If you want to isolate control circuits from nasty mains voltages or switching spikes, the
increased interwinding capacitance has to be taken into consideration. Enough could leak backwards to upset CMOS logic or microcontrollers, etc. You
always have to trade isolation for parasitic capacitance and efficiency 
Personal safety using the equipment can usually be ensured with a GFCI in the mains.
Keeping the logic happy is important. I learned many years ago that while most ICs have good protection on their inputs, they are quite vulnerable to
high energy transients on their outputs which far too often exit through the ICs inputs to the previous stages. So I worry a lot about the design where the 3V/5V logic meets the power line.
I have a piece of a power line inverter (probably from something like a 50-100 KV DC system) comprised of stacked high voltage SCRs. The trigger
transformer is unique. Each SCR has a secondary wound on some toroids spaced for high voltage. The primary is a straight wire in a thick insulating
tube passed through the center of the toroids. Lousy coupling, but at 20KV/mm, the system is set up for 100KV. I use the assembly as a hat rack. 
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12AX7
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Cute.
SCRs are an awful lot harder to handle than MOSFETs (or IGBTs). Lossy and slow, you can get a lot more power and efficiency from FETs, with far
smaller transformers because the operating frequency is higher. The same voltage and fault conditions exist (less, actually, since MOSFETs don't stay
on once you trigger them).
Dollars per weber is a curious measure for a pulse transformer. I have some which should be very expensive indeed, then; 2000 turns will easily take
several webers (not uWb!). Seems to me, a more useful measure is wattage, since the current that a given winding can be manufactured for depends on
the available winding window, which is a matter of core size.
Tim
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densest
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@12AX7 - quite true, SCRs and triacs don't want to move in a hurry, have relatively high "on" voltage, and require substantial trigger power. They're
still made in huge quantities because they're cheap, cheap, cheap, rugged, and are fast enough to use in dimmers, small variable speed motors, etc.
For those applications, no transformers are used at all - all isolation is done with insulation or open space and the drive circuits are very very
simple. Did I mention cheap? and easy to make for relatively high voltage operation and surge tolerant. All good for consumer items not needing to be
superbly efficient. Cheap. And easily made on old semiconductor manufacturing equipment in a basement somewhere.
I was using $/wb because (simplified probably too far) a trigger/gate transformer is normally used to drive a moderately high impedance (mostly
capacitive) with a defined waveform and power isn't a limiting factor. Yes, driving a FET/IGBT can require multi-ampere spikes at turn-on and
turn-off, but in between the current approaches zero. So the required performance is often limited by how long the drive can be applied before
saturation and the charge/discharge current, not by power transferred. And most manufacturers specify volt-microseconds, inductance, winding
resistance, and turns ratio as the primary characteristics of the devices. A matter of convenience, really.
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quicksilver
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I have been have OUTSTANDING luck with Power Supplies, High Voltage goodies and bits at this site (which I highly recommend):
http://www.surplussales.com/index.html
Best thing is to talk w/ them on the phone. Their "hook" is free shipping after $100 or equivalent in Euros. They have a GREAT deal of Lamda stuff, -
they seem like they enjoy "dealing"; so many prices may come down a bit.
Los Alamos stuff, & military gear. Some of the high amperage SWITCHING supplies are at $30-40 for a 5Vdc / 30A and great savings on HIGH VOLTAGE
(hard to find) components.... They also have damn good Rack mounted supplies. Some are tested - others are "as is" but all are priced accordingly.
PS - an "as is" was simply a complex multi-switching supply (5vDC @ 150a) that had no manual and in a few hours I learned to set it up (the trim pots
are wax sealed from the lab to match the material printed on the component.
That one was perfect for BIG tanks. Today I cleaned a 5 gal bucket cell which netted me 6 lbs dry KCLO3 with graphite rods and 10days but used perhaps
60a. If I wanted to deal with the graphite - I think that supply could handle a horse water feeder at 200 gal or a serious high volume plating.
[Edited on 16-3-2010 by quicksilver]
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Lambda
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| Quote: Originally posted by quicksilver |
... PS - an "as is" was simply a complex multi-switching supply (5vDC @ 150a) that had no manual and in a few hours I learned to set it up (the trim
pots are wax sealed from the lab to match the material printed on the component. ...
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@quicksilver,
You may be referring to this Power Supply:
Lambda Power Supply - Model (PS) LGS-EEA-5-OVR
Lambda regulated power supply. Over voltage protection. Original price = $1,176.00.
• Input: 105 - 132 vac @ 47 - 440 Hz
• Output: 5v @ 150a @ 40ºC reg. 0.1%, 96a @ 71ºC
• Dimensions: 4-15/16" x 7-1/2" x 16-1/2"
• $795 each
But, ... have You seen this One on the same Web Page which can Pump a Massive 300 Amps at 5 Volts !! It does have a different input Voltage of 230 VAC, instead of 105 - 132 VAC mentioned on the previous Model.
http://www.surplussales.com/PowerSupplies/PowerS-3.html
Jeta Power Supply - Model (PS) CP137
Jeta Model CP137 power supply. No manual, no cords. Not rack mountable. Mfg. P/N: 725-3308-1.
• Input: 230 vac
• Outputs: 1850 watts, V1: 5v @ 300 amps, V2: 12v @ 20 amps V3: 5v @ 10 amps, V4: 12v @ 5 amps
• Dimensions: 12" x 18-1/2" x 5"H
• $125 each
Fine Young Cannibals - The Flame (VHS Remaster):
http://www.youtube.com/watch?v=GHYdaorAKY4
Lambda
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quicksilver
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I don't have a phone camera with me or I'd post it. There's a "QSI" (sold to Lamda) w/ fans that 150a @ $40 It is a "as is". no manual, not material
at all. It was strictly a gamble. But I'LL do that;. I really know little about electronics but I worked as an electrician through the construction
industry and have a very effective way of problem solving.
I got it going and SLOWLY figured out all the idiosyncrasies. $40 for a 150amp switching supply that is MADE for 24/7 use! I was stoked. They also
have quite a few excellent 5Vdc 15a NEW supplies that simply need an enclosure, some are 5v and much higher. An enclosure is not only easy but you can
put more than one fan to create a "flow-through", that's very effective!
On another (somewhat off topic) subject I have a warning for some of you who use Gouging Rods for anodes/cathodes. IF you have prepared your rods
carefully with dilute acids to knock out the remains of copper and iron you may sill get a batch that is off color(beige). That material should
unquestionably be re-crystallized. Unless your batch is white as snow; re-crystallize. With this you take out an insurance policy. An untreated rod
will not last very long where a well treated rod may last more than 2 weeks! But introduced into the brine might be a fuel (especially if that same
rod is used for a long time).
There is a possibility that some other material was left within the the chlorate (or perchlorate) crystals. this may constitute the same as material
as a fuel, intimately mixed in the chlorate! Just like BP, the mix would be extremely intimate and the result could be very serious IF the material
was exposed to any stimulus. Re-crystallized until you have a snow white crystal. Linseed oil, shellac, carbon, etc are all fuels! The mix would be
very intimate similar to a PB mill. I strongly suggest to recrystallize, as ANY fuel with a chlorate is a serious problem. The off white color may be
an indication of some type of fuel. It may also be an indication of a simple color change from filter paper or inks; but why take a chance? This issue
generally takes place in a large cell but regardless, if you believe your resultant material may have something "extra" - do something about it.
If the material is off color when still wet, let it dry and see what takes place. A crystal can "throw off" a dye of sub micron carbon just as it can
retain it. Take a very small sample and test. PURE chlorate with no fuel should not take fire in the same manner as one with a fuel. Friction &
impact will differ also. If it acts quite sensitive - clean it further.
[Edited on 16-3-2010 by quicksilver]
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dann2
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Hello Quicksilver,
| Quote: Originally posted by quicksilver | .......... An untreated rod will not last very long where a well treated rod may last more than 2 weekks!........
[Edited on 16-3-2010 by quicksilver] |
Are you using pH controll with these rods?
Dann2
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quicksilver
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I only used untreated graphite once (those were"bars" of graphite 2"x1/2"x10") and did control ph but they broke down pretty quickly. So I shut down
and from then only used treated rods and with those -Yes; by that I mean I'll maintain 6.5-7 ph. I test at the beginning and at 2 day intervals.
However I'm using a lot of current as compared to what I had previously used. Using the formula you described previously I was pretty low before. I
don't have the numbers in front of me but I had used 3a with 2.5 L which should have been higher. I know that I'm low because with another cell with
Ti/MMO mesh I would get formation within the perforation (of crystals). Kick it up a slight bit and not crystal formation occurs in the perforations.
I believe it helps the rod's longevity (stringent ph monitoring) but I'm not convinced that the rods are consistent in porosity or density.
Opinion-wise I think that anytime enough current is moving through there to maintain 50+ C, the rods' going to "shed". I get enormous yields of
chlorate with graphite and the cost is low but the mess and lack of snow-white crystals (even from a rolling boil to re-crystallize) makes me think
that the extra work is the trade-off.
I'd be curious to try an experiment wherein a dye is placed in the tank prior to cultivation and see whether the crystal forms without it from a
single recrystallization. I pulled one after 10 days and the crystals -appear- beige, but are still moist and I am going to dry these out as the water
from graphite is SO stained that it may be I am looking at dyed water. However I have seen some that unquestionably had not been purified by a single
recrystallization. Those that were stained within the crystal were hyper-sensitive.
edit 3/17/10
well I tried 3 re-crystallization and ALMOST got that yield water-white but it still had some beige in it. I believe that it may be from the linseed
oil. I'm disappointed in it's lack of purity wherein the MMO/Ti material is about as clean as it gets from a single re-crystallization. Of course I'm
going to keep it separate and do a heck of a lot more testing to determine if it's safe. However I am pretty disappointed that such a high yield may
not be the ideal method. I'm going to try another but with a great deal of attention to ph AND I'm going t remove any outer layer of linseed oil even
if it's not obvious (this was not obvious to a greater degree) but better safe then sorry.
[Edited on 17-3-2010 by quicksilver]
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