WTB: 115V 400Hz 3ph output Power Supply - Page 1
Forum section: electronics / general

author: danielbriggs
author_rank: Regular Contributor
timestamp: November 13, 2022, 11:06:55 pm
content: Hi all,I have a piece of aircraft gear I would very much like to run up, and it requires a higher frequency AC supply, which I don't currently have at my disposal.I'm after 115V 400Hz, 3ph supply.I don't have 3ph at home, so narrowing the selection even further, would need to run off a 1ph supply (UK Mains 50Hz, 230V). [Are power supplies like this even a thing?]The spec from the datasheet of the item is:QuoteThe DC I can generate easily from my existing supplies.However, there is a PSU module from the aircraft system I don't currently have, which generates some other rails.If I can locate the correct aircraft part, and the above 115V 3ph 400Hz supply, we're good to go, if not it looks like I'll need to also generate:275V DC6.3V 400Hz 3ph26.0V AC 400Hz 1ph23.5V AC 400Hz 1phWhich I think can be done with some transformers for the AC, and rectification for the 275V DC.If anyone has any good solutions for the above, please let me know (or even reccomendations of manufactuers what sort of test gear to look for) that would be appreciated.Elgar / Behlman etc.?Ideally variable voltage and freq, and possibly currently limiting, so it's not just useful for this one project, but fixed 115V / 400Hz supplies considered if sufficiently low enough cost to justify.I don't have £1,000's to spend, so any reasonably priced options would be greatly welcomed.I have found some suitable 1ph 400Hz variable supplies, but I've drawn a blank for the 3ph output types.Thanks in advance.Dan

author: FFY00
author_rank: Contributor
timestamp: November 14, 2022, 12:48:50 am
content: Hi Dan,Looks like you want a VVVF, like this onehttps://www.ebay.com/itm/234465615825Cheer,Filipe

author: FFY00
author_rank: Contributor
timestamp: November 14, 2022, 12:57:27 am
content: Actually nevermind, I don't think you can set a constant voltage and frequency.

author: Kean
author_rank: Unknown
timestamp: November 14, 2022, 08:11:25 am
content: Some 1ph programmable AC supplies can be linked to operate in 3ph mode - e.g. the ITECH IT-M7700. But the cost for 3 of those, even at the lowest power rating, will easily be over your budget.The power requirements are a pretty important spec, and I am surprised they aren't listed.You might be lucky to find something used, especially if you have any contacts in the industry, but even 1ph programmable AC PSUs aren't all that common and thus not cheap. It might even be cheaper to design and build something yourself using a custom signal generator design and some off-the-shelf audio amplifiers.

author: james_s
author_rank: Super Contributor
timestamp: November 14, 2022, 08:35:33 am
content: Are you open to building something? AC power supplies like the ones made by Elgar and California Instruments are expensive and even the single phase models are very heavy, I have one that I just about broke my back lugging around. They are essentially a big audio amplifier with a step-up transformer on the output. Depending on the nature of the device you're trying to run, you may be able to get away with using capacitors as a static phase converter once you have a 400Hz source to work with.There are inverters that are used in some aircraft and for bench testing avionics so you could look for one of those. Anything aircraft related tends to be expensive though.

author: Zero999
author_rank: Super Contributor
timestamp: November 14, 2022, 09:42:06 am
content: If this website is correct, you have 200V phase-to-phase, 115V phase to neutral. I wonder if a variable frequency drive designed for drive a motor would do? The duty cycle would need to be set to give 200V out, rather than close to the 230V mains voltage and it would need a filter to convert the PWM output into a sine wave.https://www.powerstream.com/400hz-tutorial.htm

author: danielbriggs
author_rank: Regular Contributor
timestamp: November 14, 2022, 01:23:24 pm
content: Thanks everyone for your replies; all really good options I'll look into.Perhaps now at the risk of being in the wrong category (although I'm still looking for solutions to buy), if I were to go down the DIY or "cobbled together" route.What's everyone's thoughts on:3x of these? FPA2000-50W but in dual channel differential mode, giving me up to 140V @ and just enough current headroom?https://fr.aliexpress.com/item/4000883746888.html?gatewayAdapt=glo2fraI have a Siglent SDG2122X (technically a SDG2042X liberated) and would be open to getting a 2nd, and sync all the outputs together to get 3x phases 120˚ apart.The amplifiers would also be useful for another project involving piezos, so I'm not totally going down a "single use" bit of test kit route, if you think those amps would be up to running a 3ph 400Hz small motor? Or do those amps not like driving such loads? Forgive me I don't have much experience with using them.If the above would work, it would have the side effect of a 4th channel sync'd up with a 4th amplifier to generate the 26V AC 400Hz 1ph without the need for finding specific transformers or a variac etc. should I not be able to locate the orginal plane PSU module.Thanks again in advance.Dan

author: themadhippy
author_rank: Super Contributor
timestamp: November 14, 2022, 01:29:14 pm
content: Quoteyea they areQuote

author: jpanhalt
author_rank: Super Contributor
timestamp: November 14, 2022, 01:49:24 pm
content: Have you considered an automotive alternator without the rectifying diodes? A brief search ("Quora") indicated 400 Hz is easily obtained, and the current produced is 3-phase (https://en.wikipedia.org/wiki/Alternator_(automotive) )Unfortunately, too many years have passed since I was a child. In those days, motor-generator sets from "war surplus" stores were plenty and cheap. I had one. I brief search found nothing. Even Surplus Sales of Nebraska's 400 Hz motors are more than $400.

author: Stray Electron
author_rank: Super Contributor
timestamp: November 14, 2022, 02:39:49 pm
content: "I don't have 3ph at home, so narrowing the selection even further, would need to run off a 1ph supply (UK Mains 50Hz, 230V). [Are power supplies like this even a thing?]"Yes, and they've been discussed on this forum several times. The Elgar 251 will do what you want but it's large and heavy. (But if you can find one local to you they can usually be had cheap if you can pick it up yourself since they're not in high demand and shipping is expensive.) The good thing is that they're pretty common in MIL support companies and are readily found surplus. Other companies make similar devices, look up "Variable AC Source" or "Elgar 251" on this forum and you'll find more advice about them. You can also search the internet and or Ebay with the same terms. Manuals for the Elgar 251 and other models can be found online. Go get one and read up on what's available.

author: danielbriggs
author_rank: Regular Contributor
timestamp: November 14, 2022, 03:20:13 pm
content: Quote from: Stray Electron on November 14, 2022, 02:39:49 pmThanks! Looks like a possible solution; but I'd need two of them it seems for motor delta wiring.There's one on eBay currently in the UK; so will keep an eye out for the availability of a 2nd and that duo is one possible solution; thanks for the tip.All the best,Dan

author: KaneTW
author_rank: Frequent Contributor
timestamp: November 14, 2022, 03:43:15 pm
content: Run a VFD in 1-phase mode and attach a sine-wave filter?* Not a recommended solution, but relatively cheap compared to a proper AC PSU

author: zrq
author_rank: Frequent Contributor
timestamp: November 14, 2022, 05:15:05 pm
content: The power requirement is not that high, so if some DIY is acceptable, some signal generator, 3x class D audio amplifiers and step up transformers (reversed power transformers) may work for you.