What to do with a couple of giant thyristors? - Page 1
Forum section: electronics / projects

author: ElektroQuark
author_rank: Unknown
timestamp: May 13, 2015, 06:31:30 am
content: I have a couple of used but perfectly working thyristor modules likeTHESE.Any ideas of what to do with them?A giant reflow oven?

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 13, 2015, 06:58:07 am
content: Paper weights?

author: ElektroQuark
author_rank: Unknown
timestamp: May 13, 2015, 06:59:43 am
content: Maybe, 640grams each.

author: technix
author_rank: Super Contributor
timestamp: May 13, 2015, 07:32:29 am
content: They are capable of some very heavy duty high current switching, 800V/300A or the like. Maybe put one in the mains line of your house and roll the heaviest duty home automation ever?

author: ElektroQuark
author_rank: Unknown
timestamp: May 13, 2015, 07:38:09 am
content: The link in the first post works now.It's a 1600V and 309A baby.Useless for me.

author: technix
author_rank: Super Contributor
timestamp: May 13, 2015, 08:01:45 am
content: Quote from: EdoNork on May 13, 2015, 07:38:09 amToo bad they are too heavy to be sent internationally, or I would say that since it is half controlled half bridge rectifier someone may find it useful.If you are interested, they can be used in a high current SMPS design. With properly rated inductors, you can get 12V/250A out of it and that will be able to drive a hell lot of motors if you have a CNC conversion project.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 13, 2015, 08:08:32 am
content: Also probably not enough to do big pulses like quarter shrinkers, if you were wondering. Maybe some light duty couple kJ magnetoforming kinds of things, but make sure the inductance is always high enough to keep them OK.Tim

author: technix
author_rank: Super Contributor
timestamp: May 13, 2015, 11:02:11 am
content: Quote from: EdoNork on May 13, 2015, 07:38:09 amActually, just too bad it is not the gate turn-off type or you can run a electric truck on it. Two of them, if GTO, can safely drive 1.5kV/200A motor in a H-bridge configuration VFD and that means 300kW per motor.

author: Psi
author_rank: Super Contributor
timestamp: May 13, 2015, 11:56:08 am
content: maybe its the start of a crazy powerful solid state tesla coil driver

author: Isad
author_rank: Frequent Contributor
timestamp: May 13, 2015, 06:36:20 pm
content: Quote from: Psi on May 13, 2015, 11:56:08 amWell this is what i was gona say but somone thought before me.Would love to see that thing.

author: SeanB
author_rank: Super Contributor
timestamp: May 13, 2015, 06:43:29 pm
content: Grab some decent 1F audiophool car capacitors, and make yourself a spot welder for battery terminals and such spot welded joints. A lot easier than trying to mount a hockey puck SCR without having to buy the massively expensive mounting kit.

author: calexanian
author_rank: Super Contributor
timestamp: May 13, 2015, 10:31:55 pm
content: How about a ring launcher. Those are fun. Or a magnetizer. Capacitive charge spot welder perhaps.

author: technix
author_rank: Super Contributor
timestamp: May 14, 2015, 12:57:19 am
content: Quote from: SeanB on May 13, 2015, 06:43:29 pmSince those are half controlled half bridges, get two of them into a high current supercap charging SMPS units rated for 10V/300A and run 4 or 5 of them in parallel so you can discharge those supercaps at 1.5kA maximum. That means you can get a maximum instantaneous power of 15kW.

author: ElektroQuark
author_rank: Unknown
timestamp: May 14, 2015, 05:59:04 am
content: Some interesting ideas. A spot welder...

author: SL4P
author_rank: Super Contributor
timestamp: May 14, 2015, 06:23:51 am
content: "we're going to need bigger wire"

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 14, 2015, 06:28:43 am
content: Could be a good start for a DIY EV "supercharger".

author: TerraHertz
author_rank: Super Contributor
timestamp: May 14, 2015, 07:05:47 am
content: Crowbar overvoltage protection directly on your household mains supply?Or put it on the upstream side of the main fuses in your meterbox, and give the entire neighborhood the benefit of crowbar overvoltage protection.No seriously! The first version at least is not a bad idea.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 14, 2015, 09:18:20 am
content: Quote from: TerraHertz on May 14, 2015, 07:05:47 amNah, they're not that big. And the semiconductor fuses you'd need to put in front of them wouldn't handle enough I^2t to start heavy loads (every time the neighbor's AC starts, you have to go out and replace the $20/ea fuses..).They would be enough to switch one or a few houses on and off, which could be used for active transient or fault protection (i.e., detect fault current during one half cycle, leave it open circuit on the following cycle). But that'd be a fairly special purpose use (maybe handy for lighting circuits, or a data center, or something?).Obviously, with a 1:3 transformer tacked on there, the capacity is a lot more useful (720V instead of 240V), but that would be kind of expensive (and the fuses and nearby switchgear moreso).SCRs are the most robust of switching semiconductors, but they're hardly indestructible. Short circuits (and faults and blowing fuses) are also a few orders of magnitude more destructive than you might expect from the usual "pop"!It's also rather disappointing to have a $100 transistor that's good for all these damn amps, but to safely use it, you need $2,000 of support components and a controller. The reality of course is, semiconductors are a surprisingly small part of total cost, even in big switching applications.Tim

author: ElektroQuark
author_rank: Unknown
timestamp: May 14, 2015, 09:30:49 am
content: Nah.Definitly I will try to sell them.They are rated at about 200€ each.Would be 50€ plus shipping a fair price?

author: technix
author_rank: Super Contributor
timestamp: May 14, 2015, 10:05:00 am
content: Quote from: T3sl4co1l on May 14, 2015, 09:18:20 amSince its rating is 1.6kV/300A, try run the crowbar at 1.2kV (5x 240V mains) or 1.44kV (6x 240V mains) probably is a better idea. That is 360/432kW we are talking about and it would be a more economic neighborhood crowbar since the current is smaller.Why my gut feeling for this thread is we are about to tread megawatt power soon?

author: TerraHertz
author_rank: Super Contributor
timestamp: May 14, 2015, 10:45:36 am
content: Quote from: T3sl4co1l on May 14, 2015, 09:18:20 am"not that big" ?Itsm = 9500A for 10 mS according to the data sheet. I was thinking of these (maybe in parallel) across the A and N lines just after the main circuit breaker in the fuse box. With a circuit to turn them on if the instantaneous mains voltage went over say 500V for more than 1/4 cycle. In the literal 'crowbar protection' manner, relying on the circuit breaker to take the punishment.The background: some people think the MSM articles being put out about 'possible terrorist EMP attack/solar CME event' are propaganda primers for a deliberate widespread power grid overvoltage event, intended to destroy pretty much all grid-connected electronics. Conspiracy theory stuff, feel free to tune out if not into that kind of thing.So I was thinking that something like these might make an effective countermeasure, to at least have your own electronics not fried. Assuming you had a backup power system for afterwards.Hmm... I have 3-phase power here. With only two of those, to get guaranteed crowbar tripping of the 3-phase CB regardless of any possible phase faults, they'd have to be delta connected on two edges of the delta-connection triangle. That idea doesn't make me feel comfortable, but I can't put my finger on why it would be bad. Since plenty of motors use delta connection. Much higher dI/dt? But those triacs have really enormous dI/dt. Should survive repeated trips. As for an instance of the worst case scenario, it would only happen once.

author: Artlav
author_rank: Frequent Contributor
timestamp: May 14, 2015, 11:30:47 am
content: Quote from: TerraHertz on May 14, 2015, 10:45:36 amHuh? CME is not supposed to produce an overvoltage. It would just saturate the big transformers on the grid by inducing DC currents in ground return, causing them to blow up in the worst case.I would be more worried about a zero wire burning off in a three phase system, causing phase imbalance and 300+V in the unlucky phase's homes.That actually happens occasionally around here.

author: technix
author_rank: Super Contributor
timestamp: May 14, 2015, 11:45:47 am
content: Quote from: TerraHertz on May 14, 2015, 10:45:36 amThat is about 10kA for 10ms. Mains input is 240V and that gives a 2.4MW pulse and blow off 24kJ energy. I don't know if a circuit breaker can take that impulse.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 14, 2015, 01:21:17 pm
content: Ah yeah, that might not be so bad then.Your average magnetothermal panel breaker will take some time to open, even under short circuit conditions. I don't remember just how slow. Um...Looking at a typical Type C breaker's time curve, it looks like fault current would probably clear in under 2 cycles. So it should be pretty fast, and the Itsm rating won't be too inappropriate.Key figure is surge current. For residential 120/240V circuits, I think it's on the order of 2kA typical. So that probably would work out quite well.I would NOT recommend it for industrial purposes, where the typical interrupt rating for 480V fuses is in the 100kA rangeTim

author: technix
author_rank: Super Contributor
timestamp: May 14, 2015, 02:11:36 pm
content: Quote from: T3sl4co1l on May 14, 2015, 01:21:17 pmOkay we are knee deep in this 48MW talk now. That is some fearful power and even s 10ms pulse we are talking about 480kJ energy...

author: technix
author_rank: Super Contributor
timestamp: May 14, 2015, 02:42:59 pm
content: Another idea, Marx generator. That switched bank of caps can give you one hell of a bang.20 of those 1uF microwave caps (US$1/each) charged to 1500V each, one control pulse down the control wires, you get a 30kV 22.5 joules pulse and blow the ass out of something.Or you can use camera flash caps (usually 330V rated with a capacitance of 800uF), five of them in series to withhold 1500V, and 20 strings of 5 caps in series, 100 caps in total, that can kick out 3.6kJ at 30kV. That will definitely blow a few things, and catch the eyes of Photonicinduction

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 15, 2015, 09:07:47 am
content: Quote from: technix on May 14, 2015, 02:11:36 pmNot necessarily. At the fractional cycle level, the line inductance is significant (even at 50/60Hz), so to some extent you're just cycling reactive energy back to the utility. A large amount of fault current will be dissipated as power in the wiring though (which is, of course, what the fuses are there for).240V at 2kA is peak 480kVA, but that won't be exactly kW, for this reason. The energy is much smaller, in fact you can calculate the reactive energy if you know the power factor (or reactive power) and line frequency. 1 VAR / (2*pi*F) = 1 J, I think. If the line is 10% inductive, then the dissipated power would be about 480kW and the reactive power 48kVAR, for all of 127J energy (not a terrifically big spark inside the fuse/breaker that has to clear it, but certainly a loud pop if you're nearby!). The dissipated energy for 1 cycle would be 8kJ, but spread over a lot of heavy wire, this won't result in much temp rise.If the SCR drops a maximum of 5V under that current, it's dissipating 10kW until the fuse/breaker opens. Which isn't too bad for a device of sufficient size. (Averaged over 1 second, that's only 167-333W for a surge of one or two cycles duration.)Tim

author: DanielS
author_rank: Frequent Contributor
timestamp: May 15, 2015, 01:25:44 pm
content: Quote from: technix on May 14, 2015, 02:42:59 pmI do not think you would be able to do that with this SCR since 30kV applied to a 100µH coil would exceed the SCR's 250A/µs max di/dT by orders of magnitude. This SCR is intended for either resistive or heavily inductive loads, applications with relatively limited current change rate.

author: sean0118
author_rank: Frequent Contributor
timestamp: May 15, 2015, 03:07:29 pm
content: Quote from: Psi on May 13, 2015, 11:56:08 amGo all out, make it asingingtesla coil driver. I wonder how many dB you could get it too?

author: KerryW
author_rank: Regular Contributor
timestamp: May 15, 2015, 03:34:23 pm
content: A pulsed doppler RADAR?Excimer LASER?

author: technix
author_rank: Super Contributor
timestamp: May 15, 2015, 05:23:08 pm
content: Quote from: DanielS on May 15, 2015, 01:25:44 pmNot really as there will be 20 of those SCRs in series to withhold this 30kV.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 15, 2015, 09:46:21 pm
content: By the way, there is such a thing as magnetic pulse compression (the name just screams sci-fi, but that might betray itsuse in particle accelerators). This doesn't get you more energy (indeed you'll lose a lot to losses), but shortens the rise time considerably, useful for RF/EMP generation, or for physics, peak power, beam deflection and laser drive stuff).Tim