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Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Steve McConner wrote ...
Ash: The whole point of the SLR is that it is current limited by design. You can happily short the output and pull arcs off it. The Mazzilli is actually worse in that respect.
.
I appreciate your point Steve, but you can't vary the current from an SLR H-bridge, as far as I'm aware. You can't use it for a variable current supply. With other topologies you can vary the output current with PWM.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
You can't use PWM with a Mazzilli circuit either. It's current-fed, so it self-destructs as soon as you turn both FETs off.
The average current output of the SLR can be regulated by changing the pulse density, but that may not be any good in some applications. The industry standard way is a buck converter in the DC link, which is also what you need for the Mazzilli.
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Steve McConner wrote ...
You can't use PWM with a Mazzilli circuit either. It's current-fed, so it self-destructs as soon as you turn both FETs off.
I did mention that above, That's what attracted me to push-pull.
Steve McConner wrote ...
The average current output of the SLR can be regulated by changing the pulse density, but that may not be any good in some applications. The industry standard way is a buck converter in the DC link, which is also what you need for the Mazzilli.
Thanks for the advice. I'll look into buck converters.
EDIT: It was suggested in the chatroom that I could use an interruptor.
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
Proud Mary wrote ...
Antonio wrote ...
What is in the video? This is the right way to make long sparks. Or at least was by 1854:
I did say carefully 'ignored by all but a few,' and perhaps I was thinking of you, Antonio.
The video is of a 1908 Edison cylinder recording of "Oh, oh, Antonio" by Miss Florrie Forde:
Kkkkkkk (laughing)
Talking more seriously, I am trying to find out the destination of that giant machine. Looking at Google Books I can see that it belonged to a certain Edwin Clark by 1862. After this I could not find anything. I am trying to locate some other large machines of the XIX century too, as this:
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
The Royal Polytechnic Institution, once the home of your second machine, seems to have had quite a chequered past:
The Polytechnic became known for its spectacular magic lantern shows, pioneered by Henry Langdon Childe (d 1874), and a new theatre was added in 1848. John Henry Pepper (1821-1900) was appointed lecturer and analytical chemist in that year. He was its most famous showman, also expanding the teaching role of the Polytechnic, which began evening classes in 1856 under the auspices of the Society of Arts. By the 1870s these were formalised under the Polytechnic College. By 1841 the Institution was calling itself the Royal Polytechnic, probably due to the patronage of Prince Albert. Expansion gradually gave way to financial difficulty, reflecting a long-standing tension between education and the need for profit. A fatal accident on the premises in 1859 caused the first company to be wound up and a new one formed. Various regeneration schemes were considered, but in 1879 a fire damaged the roof, precipitating the final crisis. By 1881 the Royal Polytechnic Institution had failed, the assets sold at auction and the building (no 309 Regent Street) put up for sale. It was purchased by the philanthropist Quintin Hogg (1845-1903), and the RPI succeeded by his Young Men's Christian Institute
Registered Member #3429
Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288
Steve McConner wrote ...
Because they (we?) have no life?
Xray doesn't understand, because if he wants some enormous flaming arcs he can just grab an X-ray transformer from the heap in the corner. Using the forklift if necessary.
Or, working with HV for a living, he sees it as a powerful tool to be respected, rather than an exciting and dangerous toy.
Because they "have no life?". Well, that probably is the case for some. But in most cases, I know and completely understand that people experience high voltage as an educational, rewarding, exciting, and FUN hobby.
As for me, personally, I have spent countless hours building Tesla Coils, Jacob's ladders, and various other forms of hv power supplies. In most cases they had no practical application except to make awesome sparks and arcs.
Anyhow, I was surprised and pleased at the response that I got from my philosophical question! The eclectic range of replies extend all the way from: "Because we can." to, a technical discussion about how to improve the ZVS circuit. But I think the best answer came from Steve McConner in his reply to Dr. kv where he said: "Dr. kV: That is the idea. Kids nowadays have no attention span, and a huge host of multimedia gadgets competing for it. If the race of engineers isn't to die out, we have to bribe them with cool looking arcs, to force them to learn stuff. " WELL STATED, STEVE!
My thanks to all who have contributed to this topic!
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ZVS philosophical question
