If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #54503
Joined: Sun Feb 22 2015, 10:35PM
Location: New Zealand
Posts: 288
Justin wrote ...
nzoomed wrote ...
I just finished assembly and everything seems all sweet - for now anyways. Except i think i did one stupid thing... :(
After switching on my UD board (had it on for about 30 seconds) i noticed smoke coming from one of the GDT MOSFETS (pretty sure it was U3)
Anyway, i quickly switched it off and then realised that i had not connected the phase jumpers to the board!
I expect this was the cause, as i suspect this prevents any negative bias when idle causing them to take off and oscillate heavily? It has been fine after connecting them and nothing is hot to touch.
Question is, will it be OK, or have i cooked it? It doesnt look burnt and nothing has melted that i can see, it did not even smell from the smoke.
I wont be able to fully test it until i get my MIDI controller (next week hopefully)
But if anyone can point out to me what components are likely to be damaged, that would be great, as i will order some spares.
I have two outputs if the first one doesn't work anyway, so not all is lost.
If the magic smoke escapes, all hope is lost.
Only one of the MOSFETS smoked and was the only one that felt hot.
There are two outputs on the board itself and the other pair should still work hopefully. I think the smoke was more from solder flux on the MOSFET's joints, rather than the MOSFET itself anyway.
Not too long ago I made a add-on board for the UD2 boards and a bunch of people were asking me about it so I thought I'll post something.
Most solid state coils which use the UD2 driver invariably require the use of a large bus capacitor. This capacitor (usually several thousands of uF) looks like a short across the mains at first turn on, which can cause fuse blows / breaker trips. The solution was usually to use a large heavy variable transformer or a separate pre-charge circuit such as a phase angle controller to limit in-rush current.
I wanted a simple, reliable solution to this problem, and this led to the development of the pre-charge board. This board pre-charges the bus cap via a power resistor for an adjustable time (couple of seconds), and then bypasses it once the capacitor is charged, preventing in-rush current. I also added a few other features such as safe and automatic bus-cap discharge once power is turned off. Also, the board allows a standard IEC input jack, basic EMI filtering and also adds a thermal-cut-off capability via an external thermistor and plugs into the UD2.7's UVLO trip allowing the driver to be turned off in such a fault condition. The result is a nice little companion to the UD2 board.
Some people were asking for it so I've some leftover ones which I thought I'll offer here:
Finally, I was going to do another final round of assembled UD2 boards so if you happened to be interested in any boards, do drop me an email at loneoceans [at] gmail [dot] com since I'll be doing a round of component orders soon.
How about using a current inrush limiting resistor? I have used
EPCOS/TDK B57127P509M301
I suppose if required you could use several smaller resistance larger current versions if necessary.
Dan
That is correct, a simple way is to use a NTC which I've done so in the past and it can work just fine within some limitations
But they do have a few drawbacks including the fact that they do not work if for some reason power is turned off, the cap bank is discharged and the coil turned on while the NTC Is still hot, among other reasons. Likewise, another simple way is to use a variac, but that's big and heavy to lug around, so I made the board to address this and to add a bunch of other features too. It seemed like just using a resistor was a simple and reliable way to get this to work :)
Registered Member #54503
Joined: Sun Feb 22 2015, 10:35PM
Location: New Zealand
Posts: 288
Hi Loneoceans. I was thinking about gate voltages when i was working on my coil and was wondering if this may be a good feature to add to a future driver (i know you said you will look at designing a completley new driver rather than updating UD 2.7)
You will probably say its a waste of time, and it could very well cause other problems, but what i propose is a variable gate voltage (VGV) feature that will run the gate voltages at a minimum of say 20V (or user preset), but slowly increase the gate voltages as the current increases on the primary up to a maximum limit of either 24V, or again user preset.
I know this is not really an issue with CM300 bricks which are pretty robust, but different IGBT's could potentially benefit from this and could perhaps give more reliability.
For example, you should get away with 20V on the gates if you are running up to around 800A or so on a CM300, but ideally for better switching, this is increased to 24V, which the driver could automatically increase when it detects higher current over a preset threshold.
Perhaps rather than a variable gate voltage, it would probably make a more simple design to just switch the gate voltage up to 24V or so once the driver detects higher current.
Im interested to know if such a design would be a good addition to a driver, or would it cause more issues with phase lead and ringing etc when the voltage switches?
Registered Member #46164
Joined: Wed May 07 2014, 08:16AM
Location: California, USA
Posts: 89
So I found out the hard way that if the UVLO pot (R29) is turned too far in the wrong direction(like say if you soldered it in that way) it feeds up to 16.4V into the LM8365 and kills it.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Universal Driver 2.7 Rev C
