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Registered Member #1232
Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881
That is certainly quite compact power electronics!
On a practical note, whilst it is clearly functional, I doubt it complies with US or European safety or EMI standards. Often it is not getting high power density that is the problem in power electronics, but finding space for input and output filtering components to meet approvals standards! These tend to form a significant volume and weight of products designed for EU markets.
From a safety point of view, exposed transistor leads carrying 100 Amps, no mains switch/circuit breaker and a plastic enclosure close to the welding head don't look good!
Registered Member #99
Joined: Thu Feb 09 2006, 06:10PM
Location: florida, usa
Posts: 637
Looks to be right up our ally here at 4hv! Haha! I like the exposed transistor leads as well! So what if some of the sparking metal gets inbetween the transistor leads? BOOM makes for a good story! EMI? Oh well! Deny everything if something nasty gets back into the mains from that inverter!
Registered Member #2028
Joined: Mon Mar 16 2009, 08:13PM
Location: Norway
Posts: 319
Yeah... right...
A duty factor of 25% at 100A is just sad, but yet i think it sounds too inbelievable. Look at that tiny heatsink? The welder obviously works, i doubt the images are fake, but a welder also need some arc stability. Small/cheap welders are generally difficult to use.
And i bet that digital display will be unreadable after some showers of weld splatter
But then again, that is amazingly compact electronics.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
What's that smell? BS probably!
I'd guess that the "ground clip" wire just goes straight through the plastic box to the electrode, and it clips onto the output of a real arc welder under the table for demo purposes. The mains power cord probably just runs the display.
Why do I think this smells of BS? Well, if you were designing the world's smallest inverter, would you start by wasting 30% of the internal volume on a big chunky set of 7-segment LED displays, when you can now buy wafer-thin LCDs and OLEDs even in hobby stores?
I would also expect to see a stack of aluminium core PCBs with force cooling by a fan, not a Radio Shack plastic box and heatsink.
Registered Member #902
Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040
Steve McConner wrote ...
What's that smell? BS probably!
I'd guess that the "ground clip" wire just goes straight through the plastic box to the electrode, and it clips onto the output of a real arc welder under the table for demo purposes. The mains power cord probably just runs the display.
Why do I think this smells of BS? Well, if you were designing the world's smallest inverter, would you start by wasting 30% of the internal volume on a big chunky set of 7-segment LED displays, when you can now buy wafer-thin LCDs and OLEDs even in hobby stores?
I would also expect to see a stack of aluminium core PCBs with force cooling by a fan, not a Radio Shack plastic box and heatsink.
I have to agree... and that would explain so much "secrecy" listed in the details (I used Google to translate) - and Steve makes a very good point regarding the use of the LED type display, which makes no sense whatsoever... also, even at a 25% duty cycle that transistor would need some serious cooling, and having a passive heat sink attached to a plastic box would produce some serious hazards to the casing, and components inside so I have to call BS on this as well... while I would be happy for such a thing, I need to see some harder evidence then this.
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Matchbox size welding inverter
