[Amps] Buck Boost

[Barrie Smith]

----- Original Message ----- 
From: "jeremy-ca" <km1h at jeremy.mv.com>
To: "Robert Groh" <rgroh at swbell.net>; "Patrick Egloff" <pegloff at gmail.com>; 
"Barrie Smith" <barrie at centric.net>
Cc: <Amps at contesting.com>
Sent: Monday, April 28, 2008 11:30 AM
Subject: Re: [Amps] Buck Boost


> Im curious as to what benefit will there be to raising the HV only 10%?

The most important reason is that I will be able to more closely match the 
secondary of the modulation transformer.

The second reason is "because I can and want to, just for fun".
>
> Its not going to raise the output enough to be heard on the other end but 
> it will add another 10% + strain on both windings.
>
> Depending upon the transformer design you may not even be able to obtain 
> that 10% at full load.

Won't know until I try it.  The HV transformer is a commercial unit, 1 amp 
CCS, and the most I'll will be drawing will be 600 mils, so I have high 
hopes.

73, Barrie, W7ALW

>
> Ive used a filament xfmr wired in Buck mode several times to reduce the HV 
> but not in Boost to raise it.
>
> A boost is also an easy way to get a Tailtwister brake to pull back.
>
> Carl
> KM1H
>
>
> ----- Original Message ----- 
> From: "Robert Groh" <rgroh at swbell.net>
> To: "Patrick Egloff" <pegloff at gmail.com>; "Barrie Smith" 
> <barrie at centric.net>
> Cc: <Amps at contesting.com>
> Sent: Monday, April 28, 2008 1:47 PM
> Subject: Re: [Amps] Buck Boost
>
>
>>I think the usual idea is to increase the primary voltage by 10% - e.g.
>> by putting a small 12V (output) transformer in series with the 120VAC
>> line or putting a small 24 V (output) transformer in series with the
>> 240 Vprimary. The small transformer only (!) needs a current rating
>> equal to the primary current on the big guy. For example, a 240 to 2400
>> V plate transformer with 1A secondary would have about 10A primary
>> current (actually need to add a bit to account for transformer
>> efficiency) so we would need a 24 VAC transformer with a 10A
>> capability.
>>
>> Using the primary means we don't muck up the center tap on the
>> secondary - if that is a concern. Also (possibly) lower voltages on the
>> 'boost' transformer. Dynamic performance could be affected.  I've only
>> done this for low power units so can't speak to the impact on high
>> power units.
>>
>> 73
>> Bob, WA2CKY
>>
>>
>> ----- Original Message ----
>> From: Patrick Egloff <pegloff at gmail.com>
>> To: Barrie Smith <barrie at centric.net>
>> Cc: Amps at contesting.com
>> Sent: Monday, April 28, 2008 11:39:53 AM
>> Subject: Re: [Amps] Buck Boost
>>
>> Sorry for that, what might seem dumb, question. But what is this "boost
>> method" ??
>>
>> An easy way to increase you HV by 10 % is to put a small transformer in
>> serial with you actual HV transformer secondary. If you have a 2000V
>> secondary, put a 150-200V in series. You must check if your new 
>> transformer
>> is highly enough insulated.
>> You can also make a 200V DC supply and put it in serial with your actual 
>> DC
>> supply.
>>
>> I did that on one supply and it works perfectly. I did put it on the DC
>> grounded side, so insulation is not so critical.
>>
>> 73, Patrick
>>
>>
>> 2008/4/28 Barrie Smith <barrie at centric.net>:
>>
>>> I'd like to increase the output voltage about 10% on a HV plate
>>> transformer using the boost method.
>>>
>>> Does anyone know what penalties I may encounter using this proceedure?
>>>
>>> Since there's no free lunch, I'm thinking that the voltage regulation 
>>> will
>>> be similar to what it would be when using a variac.  Is that true?
>>>
>>> The plate transformer I will be using is 1 amp, CCS.  If the boost
>>> transformer is stout, as well, I don't think the regulation will be to 
>>> bad.
>>>
>>> Ideas?
>>>
>>> 73, Barrie, W7ALW
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>>
>>
>> -- 
>> Patrick Egloff - TK5EP
>> email : pegloff at gmail.com
>> Web page : http://tk5ep.free.fr
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>
>