[ARC5] [Milsurplus] Quieting A DC/DC Converter

[Peter Gottlieb]

Fair probably has a lot of them still in their warehouses.



On 1/21/2018 6:35 PM, MICHAEL ST ANGELO wrote:
>
> The trick is finding surplus transformers. Does anyone know of any sources?
>
>
> I haven't looked for surplus transformers for years and started looking for a 
> good candidate for a 115VAC 400hz supply. I could not find any surplus 
> sources. Could it be surplus went to the metal recyclers because of the high 
> price of copper?
>
>
> Mike N2MS
>
>
>> On January 21, 2018 at 3:31 PM Peter Gottlieb wrote:
>>
>>
>> Probably better if you can find a surplus 400 Hz filament transformer with
>> center tap. Less iron.
>>
>>
>> On 1/21/2018 2:26 PM, Tom Lee wrote:
>>> Sorry if this has already been discussed, but making the controller go at
>>> 800Hz isn't the big challenge - it's the magnetics. Core loss is proportional
>>> to frequency, so going from 50Hz to 800Hz means a 16x increase in core loss.
>>> Whether that's a problem or not depends on the numbers, but in any case, it
>>> needs to be taken into account.
>>>
>>> Tom
>>> -- 
>>> Prof. Thomas H. Lee
>>> Allen Bldg., CIS-205
>>> 420 Via Palou Mall
>>> Stanford University
>>> Stanford, CA 94305-4070
>>> http://www-smirc.stanford.edu
>>> 650-725-3383 (public fax; no confidential information, please)
>>> On 1/21/2018 11:08 AM, Tom B wrote:
>>> >
>>> >
>>>> Here is a link to a schematic using the IR2153.
>>>> http://danyk.cz/menic230_4_en.html
>>>> It looks pretty simple to change the frequency.
>>>>
>>>> Tom
>>>>
>>>>
>>>>
>>>>
>>>> On 1/21/2018 11:21 AM, David Stinson wrote:
>>>> >
>>>>> Anyone have the link to the schematic?
>>>>>
>>>>> *From:*arc5-bounces at mailman.qth <mailto:*arc5-bounces at mailman.qth>.net 
>>>>> [mailto:arc5-bounces at mailman.qth <mailto:arc5-bounces at mailman.qth>.net]
>>>>> *On Behalf Of *Bob kb8tq
>>>>> *Sent:* Sunday, January 21, 2018 8:14 AM
>>>>> *To:* J Mcvey
>>>>> *Cc:* arc5 at mailman.qth <mailto:arc5 at mailman.qth>.net
>>>>> *Subject:* Re: [ARC5] [Milsurplus] Quieting A DC/DC Converter
>>>>>
>>>>> Hi
>>>>>
>>>>> Here’s a guy with a schematic of the same thing running a 2153. I’d bet what
>>>>> is on
>>>>>
>>>>> the board is pretty close to what he shows.
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>>
>>>>> On Jan 21, 2018, at 9:09 AM, J Mcvey via ARC5 <arc5 at mailman.qth 
>>>>> <mailto:arc5 at mailman.qth>.net
>>>>>> wrote:
>>>>> By the spec sheet for the IR2153D, you absolutely can run it at 800 Hz.
>>>>>
>>>>> Just change the R-C values accordingly.
>>>>>
>>>>> On Sunday, January 21, 2018 1:19 AM, Peter Gottlieb <kb2vtl at gmail.com 
>>>>> <mailto:kb2vtl at gmail.com>
>>>>>> wrote:
>>>>> Not sure what chip they use on the thing and how freq is set. Anyone have one
>>>>> and can let us know what the 8 pin DIP is?
>>>>>
>>>>>
>>>>> On 1/21/2018 12:50 AM, JOHN MCCARTY wrote:
>>>>>> This is cool. My question is: can we up-scale the thing and make it run at
>>>>> 800hz??
>>>>> >
>>>>>> 73
>>>>>>
>>>>>> n9hrt
>>>>
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