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Re: DC current sources

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Ian Field wrote...
>
> Winfield Hill wrote...
>> Martin Brown wrote...
>>>
>>>On 03/05/2017 13:15, Clifford Heath wrote:
>>>> A friend works in concrete reinforcing corrosion remediation,
>>>> and has been asked to take over a project that's underway
>>>> despite not having been properly designed or specified.
>>>>
>>>> The contractors are installing 400 anodes into the structure,
>>>> and each one needs a specific amount of charge to be deposited
>>>> into it, all over a week or two. The resistance is unknown and
>>>> could change from day to day, but the voltage must not rise
>>>> above +9V, or the titanium wires rapidly corrode. So they
>>>> want to adjust the current for each anode, probably in the
>>>> range of 100ma to 3000mA. They're intending to feed the whole
>>>> protection thing from banks of 12V lead acid batteries, I
>>>> guess because it's a remote site.
>>>
>>> Why not use a high power switched mode DC to DC converter
>>> to supply 8.5v to the anodes through a crude rheostat and
>>> power resistor?
>>
>> Or buck smps down to 9.7 volts and an LM317 with resistor
>> current limiting for each, w/o overheating issues.  LM317
>> thermal limits, protecting itself in case of shorts, etc.
>
> But it won't do the 3A top limit mentioned - 

 Oh, sorry (referring quickly to AoE Table 9.2), I meant
 the LM350T (3A) or the LM338T (5A), in TO-220 packages.
 Or if pressed, a few LM317 (1.5A) in parallel.  Examine
 the spec sheets to see if more than 9.7 volts is needed.


-- 
 Thanks,
    - Win

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DC current sources Clifford Heath <no.spam@please.net> - 2017-05-03 22:15 +1000
  Re: DC current sources George Herold <gherold@teachspin.com> - 2017-05-03 05:55 -0700
    Re: DC current sources "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-03 19:40 +0100
      Re: DC current sources tabbypurr@gmail.com - 2017-05-06 00:39 -0700
  Re: DC current sources Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2017-05-03 14:06 +0100
    Re: DC current sources Winfield Hill <hill@rowland.harvard.edu> - 2017-05-03 11:06 -0700
      Re: DC current sources "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-03 19:43 +0100
        Re: DC current sources Winfield Hill <hill@rowland.harvard.edu> - 2017-05-03 13:02 -0700
          Re: DC current sources Winfield Hill <hill@rowland.harvard.edu> - 2017-05-03 17:22 -0700
        Re: DC current sources tabbypurr@gmail.com - 2017-05-06 00:41 -0700
  Re: DC current sources "dcaster@krl.org" <dcaster@krl.org> - 2017-05-03 06:15 -0700
  Re: DC current sources Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-05-03 11:10 -0400
  Re: DC current sources Tim Wescott <tim@seemywebsite.com> - 2017-05-03 11:27 -0500
    Re: DC current sources "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-03 19:47 +0100
      Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-04 12:41 +1000
        Re: DC current sources "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-04 20:55 +0100
          Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-05 08:39 +1000
  Re: DC current sources "dcaster@krl.org" <dcaster@krl.org> - 2017-05-03 09:37 -0700
  Re: DC current sources Tim Wescott <seemywebsite@myfooter.really> - 2017-05-03 13:53 -0500
    Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-04 12:24 +1000
      Re: DC current sources mike <ham789@netzero.net> - 2017-05-04 00:48 -0700
      Re: DC current sources whit3rd <whit3rd@gmail.com> - 2017-05-04 14:09 -0700
        Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-05 08:42 +1000
  Re: DC current sources mike <ham789@netzero.net> - 2017-05-03 13:22 -0700
  Re: DC current sources whit3rd <whit3rd@gmail.com> - 2017-05-03 13:25 -0700
    Re: DC current sources Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-03 13:45 -0700
      Re: DC current sources whit3rd <whit3rd@gmail.com> - 2017-05-03 15:40 -0700
        Re: DC current sources Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-03 16:04 -0700
      Re: DC current sources krw@notreal.com - 2017-05-03 21:26 -0400
    Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-04 12:27 +1000
  Re: DC current sources John Robertson <spam@flippers.com> - 2017-05-03 22:48 -0700
    Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-04 16:36 +1000
  Re: DC current sources Jasen Betts <jasen@xnet.co.nz> - 2017-05-04 04:59 +0000
    Re: DC current sources Chris Jones <lugnut808@spam.yahoo.com> - 2017-05-04 22:50 +1000
    Re: DC current sources tabbypurr@gmail.com - 2017-05-06 00:53 -0700
  Re: DC current sources John Robertson <spam@flippers.com> - 2017-05-03 23:38 -0700
    Re: DC current sources Clifford Heath <no.spam@please.net> - 2017-05-04 16:45 +1000
      Re: DC current sources John Robertson <spam@flippers.com> - 2017-05-04 11:16 -0700
    Re: DC current sources Winfield Hill <hill@rowland.harvard.edu> - 2017-05-04 14:32 -0700
      Re: DC current sources "Ian Field" <gangprobing.alien1@virginmedia.com> - 2017-05-05 20:21 +0100
      Re: DC current sources Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-05-06 05:59 -0700
        Re: DC current sources Steve Wilson <no@spam.com> - 2017-05-06 14:04 +0000
  Re: DC current sources Robert Baer <robertbaer@localnet.com> - 2017-05-04 19:32 -0800
    Re: DC current sources mike <ham789@netzero.net> - 2017-05-05 00:18 -0700
      Re: DC current sources Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-05-05 08:28 +0000
        Re: DC current sources Robert Baer <robertbaer@localnet.com> - 2017-05-05 22:09 -0800
          Re: DC current sources Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-05-06 06:17 +0000
            Re: DC current sources Robert Baer <robertbaer@localnet.com> - 2017-05-06 20:47 -0800
              Re: DC current sources Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-05-07 08:27 +0000
      Re: DC current sources Robert Baer <robertbaer@localnet.com> - 2017-05-05 22:07 -0800

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