[Milsurplus] 400 Hz Power

[J. Forster]

Not so much in a noisy lab with potted transformers.

-John

===========


> Much easier:  I check it with my ears.  The 400 Hz sound is unmistakable!
>
>
> On 1/16/2011 4:41 PM, J. Forster wrote:
>> A Cautionary Tale:
>>
>> A few years ago, I got a commercial static inverter with a set of
>> frequency select switches on the front panel plug-in.
>>
>> I hooked the unit up to a NOS BC-929-A display and powered it up. The
>> scope came to life nicely....  for a couple of minutes, then poof!
>>
>> Turns out, IU missed the decimal point on the frequency set module...
>> aircrafdt stuff really does not like 115 V at 40.0 Hz.
>>
>> Moral:  Check your power with a scope!!
>>
>> -John
>>
>> ================
>>
>>
>>
>>> Quite a number of VFDs for motors can go to 400 Hz and are 3 phase.
>>> There are some that will work on single phase input right off the
>>> shelf,
>>> however, most of the larger ones are configured for 3 phase input and
>>> so
>>> if all you have is single phase you will need to do some mods to the
>>> front end rectifier circuit.  I've used these things successfully to
>>> run
>>> 400 Hz equipment and the modern ones are PWM and put out a decent
>>> looking sine wave.  You'll want one with a keypad for setting
>>> parameters
>>> or you're going to be searching out software to connect and program the
>>> thing, which you should try to avoid.  They can be set to power up to a
>>> certain state, such as 400 Hz output.  Each horsepower of rating will
>>> put out 746 watts, so for example a 4 HP drive is good for about 3 kW.
>>> Select a 120/208 output unit.  This is the most efficient way to get
>>> 400
>>> Hz in your lab.
>>>
>>> Peter
>>>
>>>
>>> On 1/16/2011 3:04 PM, Richard C. Grosser wrote:
>>>> There seems to be a lot of people interested in a source of 400hz 3
>>>> phase
>>>> power. I have an old rotary inverter from a PBY, however it is very
>>>> heavy
>>>> and very noisy. I have designed and built a relatively simple static
>>>> inverter that supplies 110 vac 400hz 3 phase as well as 24 vac 400hz
>>>> single
>>>> phase. It is quite small ( 10" x 10" x 4") and weighs less than 10
>>>> lbs.
>>>> I
>>>> built the digital circuit on a wire wrap board. If someone has the
>>>> time
>>>> or
>>>> interest in designing a circuit board, I can make the Cadence OrCad
>>>> files
>>>> available to them. In the mean time, the circuit is available for
>>>> download
>>>> at www.richardgrosser.net/inverter.pdf.
>>>>
>>>> If you have any questions, email me at Richard at richardgrosser.net
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Enjoy!
>>>>
>>>>
>>>>
>>>> Richard C. Grosser
>>>>
>>>> Palm Springs Air Museum
>>>>
>>>> 745 N. Gene Autry Trail
>>>>
>>>> Palm Springs, CA 92260
>>>>
>>>> (760) 778-6262 X231
>>>>
>>>> Cell: (760)-898-6888
>>>>
>>>>
>>>>
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>>
>>
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