What to do with a huge-ass TRIAC? - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: November 01, 2018, 01:04:40 pm
content: When I went to my usual passive component supplier for some supplies, she gave me a usedBTA41-800B 800V 41A TRIACas a bonus out of blue.What can I do with that?

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 01, 2018, 01:17:04 pm
content: It would work great to control a large heating element. In fact, that's probably the biggest use case for large triacs.

author: technix
author_rank: Super Contributor
timestamp: November 01, 2018, 01:19:59 pm
content: Quote from: NiHaoMike on November 01, 2018, 01:17:04 pmI cannot see me getting a 32kW heating element any time soon... That thing can switch 32kW of power.

author: Wolfgang
author_rank: Super Contributor
timestamp: November 01, 2018, 01:29:17 pm
content: It could be used as a crowbar.

author: capt bullshot
author_rank: Super Contributor
timestamp: November 01, 2018, 01:30:46 pm
content: TO-243 - that's a neat small oneAnyway, most probably at the upper end of your typical Triac rated current range.SCRs can do more, and way better suited as a crowbar than a triacImagine discharging a 900V / 500uF cap through some innocent compents (such as your triac), this SCR does a good execution job here (use it as the discharge switch).

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 01, 2018, 01:34:47 pm
content: The 800V rating gives plenty of margin for spikes on a 240V supply and after a 20% derating on the current, a more realistic max load would be about 7.5kW.As for another use, maybe switching the primary of a large transformer used for spot welding?

author: Messtechniker
author_rank: Frequent Contributor
timestamp: November 01, 2018, 01:37:59 pm
content: I'd put it in my collection of trannies and alike for subsquent use at the old pensioners home when I grow old. There, to have some fun, explode a small tranny every weekday and on sundays a larger one. Will frighten the life out of the "wardens". Keep the large TRIAC for X-mas.....Don't forget to maintain a largish LION battrey fully charged for this purpose.

author: capt bullshot
author_rank: Super Contributor
timestamp: November 01, 2018, 01:40:41 pm
content: Quote from: NiHaoMike on November 01, 2018, 01:34:47 pmYes, one can find a triple of them in a typical three phase powered hot water boiler, rated at total 18 ... 24kW.

author: technix
author_rank: Super Contributor
timestamp: November 01, 2018, 01:41:10 pm
content: Quote from: NiHaoMike on November 01, 2018, 01:34:47 pmI think I can get a few supercaps for relatively cheap, and this thing can tank 400A pulses no longer than 50ms... And I do have a few 19.5V 3A mains switch power supply (a genuine Dell laptop power brick and two bare board style power modules) for charging the caps through a switch mode constant current regulator.Quote from: capt bullshot on November 01, 2018, 01:30:46 pmWhat is the ratings on that one? Megawatt scale?Quote from: Messtechniker on November 01, 2018, 01:37:59 pmBrrr...

author: capt bullshot
author_rank: Super Contributor
timestamp: November 01, 2018, 01:51:55 pm
content: Quote from: technix on November 01, 2018, 01:41:10 pmhttp://ixapps.ixys.com/datasheet/mcd200-16io1.pdf216A DC continuous / 1600V, 8kA surge. More interesting for capacitor discharging is the I2t value, this gives you some hint how much energy this thing can absorb in a single pulse. Sometimes a limit for "explosive disintegration" is specifiedAt best a "medium size" for real power electronics ... Might be used for the line rectifier of a 300kW inverter / VFD.QuoteNaah, not brrr, rather have fun, fun, fun

author: technix
author_rank: Super Contributor
timestamp: November 01, 2018, 01:57:32 pm
content: Quote from: capt bullshot on November 01, 2018, 01:51:55 pmHow to understand that I2t value?

author: capt bullshot
author_rank: Super Contributor
timestamp: November 01, 2018, 02:02:15 pm
content: Quote from: technix on November 01, 2018, 01:57:32 pmSame as for fuses. We call it "Schmelzintegral" in German, it's the integral of current² over time flowing through the device. If the specified value is exceeded in a single pulse / short enough time, the device fails / the fuse trips.Usually the I²t for fuses is larger than for (comparable) semiconductors, so the semiconductor device protects the fuse. The fuse is still there, to limit collateral damage.