115V, 400Hz Power Supply - Need help - SOLVED!!! THANKS AND CHEERS! - Page 1
Forum section: electronics / general

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 10, 2019, 05:19:17 pm
content: I have an aviation device that requires 115V 400Hz that may pull up to 2A. I know that the multi product calibrator will not supply this. I have a tektronix CFG250, but I believe it is limited in the input voltage. Other than purchasing an AC Power Supply (which is a couple of thousand dollars), does anyone out there have any recommendations on the quickest way to generate such a voltage/frequency/sustainable current.I came across this little bit fromhttp://www.aerospaceweb.org/question/electronics/q0219.shtmlFinally, running a piece of 400 Hz equipment on a 60 Hz electrical system is not advised since it will damage the device. If the same voltage is supplied to the 400 Hz device as to a 60 Hz item, it will cause the metal in the 400 Hz unit to overheat. The end result will almost surely be smoke and possibly a fire. This problem can usually be avoided, however, simplyby reducing the voltage supplied to the device by a ratio of 60/400, or 0.15. A reduction in voltage to 15% of its original value at the same current will allow most 400 Hz devices to operate safely on a 60 Hz electrical system.Is this correct, and if so, what method would you recommend to do something like that.Please - experienced answers only as this piece of equipment will not be subjected to "trial and error". I'm doing my due diligence prior to performing any action.Thanks as always - ya'll are great.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 10, 2019, 07:35:14 pm
content: Signal generator, audio power amp and step-up transformer. Not difficult but you need to choose a decent amp that's robust.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 10, 2019, 08:03:24 pm
content: I suggest hacking a cheap power inverter.

author: Emo
author_rank: Regular Contributor
timestamp: February 10, 2019, 08:23:19 pm
content: HiThe EGS8010/IR2110 units do have a setting for this. So the very affordable inverter circuits on eBay will be able to fullfill your specifications easilyOne of the jumper settings does mention; 0-400Hz adjustable frequency sine-waveEric

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 12, 2019, 05:12:06 pm
content: I think it may be prudent to purchase a dedicated AC Power supply with variable frequencies.Does anyone in the community have a recommendation for a lower tier AC Power supply capable of 115 V, 400 Hz, and can handle a current draw of 2 A. Have used some of the BK models in the past and will be looking at their spec sheets today.

author: tomato
author_rank: Regular Contributor
timestamp: February 12, 2019, 08:44:36 pm
content: Quote from: itsbiodiversity on February 12, 2019, 05:12:06 pmI'm not sure what your budget is, but I have had very good luck with Pacific Power Source (AMX series) AC power supplies.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 12, 2019, 09:31:44 pm
content: Quote from: tomato on February 12, 2019, 08:44:36 pmPPS and/or Elgar brand power supplies. I've used both and they're build to do exactly what you want. No kludges or hodge-podges. The Elgars (my 251 models anyway) have a removable plug in master oscillator the controls the frequency, you can buy fixed frequency oscillators or variable frequency oscillators. The voltage out is set from the front panel or a remote programer option.

author: Yansi
author_rank: Super Contributor
timestamp: February 12, 2019, 09:54:48 pm
content: any 400Hz source (PC sound card, signal gen., ...), any audio power amp with suitable power output (preferably a class D due to much lower dissipation) and a sutable step-up transformer with the right voltage ratio.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 12, 2019, 10:32:08 pm
content: would the tektronix CFG250 i have be able to serve as the 400 hz source (I know it does this range)? it can output 0-20 V p-p and 0-2 v p-p with sine wave. I will mention that the item being powered up has a 2 amp fuse but I am not 100% on what the exact draw is.Also - would something like this work:https://www.ebay.com/itm/Elgar-Power-Supply-Model-251/332620008582?hash=item4d71b28c86:g:v4kAAOSwsTdazoXc:rk:3:pf:0? I know it's pretty beat up, but just using that as an example. Do you use a sig gen hooked to the input of this unit to vary the frequency? also odd why is there a DC V panel meter on the AC supply?

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 12, 2019, 11:05:46 pm
content: also spotted this unit.https://www.ebay.com/itm/Elgar-121B-200-AC-Power-Source-0-120VA-0-260Vac-45Hz-10Khz/283357765583?epid=726108618&hash=item41f9705fcf:g:FOMAAOSwakJcT-vI:rk:20:pf:0mentions no oscillator. would the tektronix be able to supply that frequency to this unit?

author: Yansi
author_rank: Super Contributor
timestamp: February 12, 2019, 11:10:08 pm
content: Forget that unit, it is only 120VA (probably a nice linear amplifier / hot air furnace). Your spec needed was 115V 2A (230VA).

author: james_s
author_rank: Super Contributor
timestamp: February 12, 2019, 11:59:50 pm
content: Those are linear. My friend's company has a larger unit that is otherwise similar to that, it's about an 8U rack cabinet and weighs a few hundred pounds. Inside is a huge transformer and a linear amplifier made from banks of 2N3055 transistors on a huge heatsink. It produces a tremendous amount of heat but it makes it easy to have 50/60/400Hz or any other arbitrary frequency at anywhere up to about 300VAC. Great for testing magnetics, but I wouldn't want to use it to power something long term.

author: Yansi
author_rank: Super Contributor
timestamp: February 13, 2019, 01:01:19 am
content: We have such old beauties at work too - mainly to test performances of active PFC circuitry on a very clean power supply with low distortion.I do not know about the large unit, the smaller ones are I think 300VA units, and are I think 3U units. They all I think HP/Agilent units. Not sure off hand the part no.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 13, 2019, 01:22:19 am
content: Quote from: itsbiodiversity on February 12, 2019, 10:32:08 pmWTF? That should be an AC voltmeter. I suspect that the original died and someone replaced it with a DC meter and some rectifiers. I don't think the originals were marked Simpson either.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 13, 2019, 01:29:15 am
content: Quote from: itsbiodiversity on February 12, 2019, 11:05:46 pmI don't know anything about the oscillators that use an external input but I would think that they wouldn't draw much power. However the Elgar 121 is probably only rated for about 120 VA output so I don't think it's really large enough for your application. I know that the Elgar model 251 is rated for approximately 250 VA so it should work. The much scarcer model 501 has twice the output and probably twice the weight. If possible, I would look for a power source with it's own oscillator instead of relying on an external one.PS I just looked at the power source with the DC meter again. That's definitely non-original. The originals have the voltage scale on them (like that shown in your second link) and not a 0 to 10 scale.

author: tomato
author_rank: Regular Contributor
timestamp: February 13, 2019, 01:57:47 am
content: Again, I don't know what your budget is, but this is a decent price for a new unit:https://www.ebay.com/itm/PACIFIC-POWER-SMARTSOURCE-115-ASX-UPC1M-15-1200Hz-0-132Vac-1500VA-NEW/232250883695?epid=807161753&hash=item36133b3e6fI paid quite a bit more for the same power supply many years ago.

author: tatersalad
author_rank: Contributor
timestamp: February 13, 2019, 02:08:30 am
content: I work on flight simulators and we use 400hz 115v converters I was able to track down 1 of them but its an aircraft part so im sure its stupid expensive but im betting we have a non aircraft version, if not I can always open it up and take some pictures and get you some details. Im back in Thursday afternoon ill keep trying. I know for a fact it wont like 60hz... we have tried and we failed.

author: Yansi
author_rank: Super Contributor
timestamp: February 13, 2019, 03:00:01 am
content: Trying 60Hz on a 400Hz equipment is downright ... well wrong. You can damage it! Most of the tech uses transformers in the power supplies, that will saturate at low frequency and burn out.If I was to build a frequency converter for this purpose, I'd just use a PWM modulated H-bridge, with suitable low pass filtering network. I'd say that there is nothing that fancy in such frequency converter. The more intricate part is to make it robust (short circuit, overload, etc) and EMC compliant, along with appropriate output signal clarity (distortion, voltage precision, output impedance,..)

author: tatersalad
author_rank: Contributor
timestamp: February 13, 2019, 05:18:30 am
content: We had a downed sim and at 30k an hour it was worth a shot for some electroluminescent backlighting for switch panels. We tested it on a old panel we had for a sim we decommissioned so we had nothing to loose. We would never try it with the avionics. That would be way more than dumb at 100k per display!

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 13, 2019, 01:16:17 pm
content: I was trying to stay around $1k USD for the supply, even though that model from Pacific on ebay looks great. I will update this with the route I choose. If anyone knows of a sub $1k, ready made AC Power supply that serves this function I would love your input. Thanks for everyone chiming in, and I have learned a ton even researching this topic.

author: james_s
author_rank: Super Contributor
timestamp: February 13, 2019, 07:05:44 pm
content: It seems like there has got to be something for under $1k, I mean certainly one could build something that would do the job for a lot less, you probably don't even really need a proper sine wave. A VFD may be able to do the trick, many of them will go way beyond 60Hz. Most are designed to drive 3 phase motors but I'm pretty sure some can drive single phase loads.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 14, 2019, 01:49:41 am
content: I was lucky and bought a physically small metered bench type variable frequency power supply locally for about 5% of what they normally sell for. The output can be either 120/240 VAC at up to 2.5 amps, as long as you don’t exceed the 200 VA (about 1.7A @ 120V) output power rating of the unit, which is too small for your needs. The output is voltage regulated at the set voltage and the output is a nice looking sine wave. I’ve seen a couple updated versions of this supply on eBay and they aren’t cheap.Here’s a few photos showing the unit I have including the inside view. I will say that the power supply I have is very well made but I wouldn’t have paid what they are asking (~$800) for these units because I couldn’t justify that much money for my occasional use.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: February 15, 2019, 11:30:08 pm
content: I appreciate all of the replies. We ended up using an Audio Amplifier with a Signal Generator. Checking the output from transformers with Fluke 8846A showed stable, and repeatable voltage and frequency. Clear signal. Pictures attached. Aircraft test unit functioned on supply and all is right in the world. THANK YOU ALL!

author: Yansi
author_rank: Super Contributor
timestamp: February 17, 2019, 04:40:20 pm
content: Well done! Even a proper QSC Amplifier.

author: angelG
author_rank: Newbie
timestamp: May 30, 2023, 02:30:29 pm
content: Hellowe have a similar issue, we need to test polarity in a brake coil assembly, need provided a 115v to 400Hz signal.Could someone confirm if any of the setups proposed here are ideal?