On Tue, 20 May 2014 21:31:44 -0400, "Maynard A. Philbrook Jr."
<jamie_ka1lpa@charter.net> wrote:


>> The OP said 200 (TWO HUNDRED) amps.
>> Nothing mentioned so far comes anywhere near being capable of 200 AMPS. 
>> :-?
>
>Large variac with rectifier ?

OP already has the power supply and motor.  A carbon pile rheostat is
the perfect solution to this problem.  I have such a beast but I'm not
parting with it :-)

I spent part of yesterday looking for a modern day carbon pile maker
for another problem.  Couldn't find one, though I ran into a couple of
custom resistor companies who could probably make them.

To the OP:  Try Alibaba.com.  If they're still made, the ChiComs or
the Indians will make them.

If you really can't find one then you might take a look at some of the
less expensive EV motor controllers.  Still several hundred dollars
but a positive and stable solution.

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com 
Tellico Plains, Occupied TN
See website for email address

OldGuy <spamnot@nospam.com> wrote:

> Who makes a good stable carbon pile?
> Stable as in it maintains its resistance as current is varied.
> 200 amp range, 100 VDC.
> Currently using a battery load tester but I want something I can mount
> on my own equipment.
> 
> e.g. I have DC motor that I want to voltage up to see how it draws.

I don't think a carbon pile would be particularly stable, especially as
it heats up.  You could include it in a feedback loop and use an
electromagnet to vary the pressure so as to keep it stable, but that
would involve some way of monitoring its resistance.

For low resistance high current purposes, big wirewound resistors with
multiple tappings are the cheapest and most stable answer.  They are
relatively easy to construct from slate bars and resistance wire, but
the tapping switch is going to be the most difficult item to design and
make.

If you want to go down this route, please ask for more information.  I
have made several 5 kW* units as replacements in motor-starting
applications, so I may be able to help.

http://www.poppyrecords.co.uk/other/images/CBAT01_0937s.jpg




*Intermittent rating.

-- 
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Maynard A. Philbrook Jr. used his keyboard to write :
> In article <9oGdncjuh_FYc-bOnZ2dnUVZ_qWdnZ2d@westnet.com.au>, 
> greentest@ozemail.com.au says...
>> 
>> wanderer wrote :
>>> On Wednesday, May 14, 2014 7:21:42 PM UTC-4, OldGuy wrote:
>>>> Who makes a good stable carbon pile?
>>>> 
>>>> Stable as in it maintains its resistance as current is varied.
>>>> 
>>>> 200 amp range, 100 VDC.
>>>> 
>>>> Currently using a battery load tester but I want something I can mount 
>>>> 
>>>> on my own equipment.
>>>> 
>>>> 
>>>> 
>>>> e.g. I have DC motor that I want to voltage up to see how it draws.
>>> 
>>> Look for sewing machine foot pedals. The old ones had carbon piles and the 
>>> new ones might be an alternative to carbon piles.
>> 
>> The OP said 200 (TWO HUNDRED) amps.
>> Nothing mentioned so far comes anywhere near being capable of 200 AMPS. 
>> :-?
>
> Large variac with rectifier ?
>
> Jamie

20KVA  is a big Variac and a big rectifier.
I wonder if the OP really meant such a large job? :-Z

-- 
John G

In article <9oGdncjuh_FYc-bOnZ2dnUVZ_qWdnZ2d@westnet.com.au>, 
greentest@ozemail.com.au says...
> 
> wanderer wrote :
> > On Wednesday, May 14, 2014 7:21:42 PM UTC-4, OldGuy wrote:
> >> Who makes a good stable carbon pile?
> >> 
> >> Stable as in it maintains its resistance as current is varied.
> >> 
> >> 200 amp range, 100 VDC.
> >> 
> >> Currently using a battery load tester but I want something I can mount 
> >> 
> >> on my own equipment.
> >> 
> >> 
> >> 
> >> e.g. I have DC motor that I want to voltage up to see how it draws.
> >
> > Look for sewing machine foot pedals. The old ones had carbon piles and the 
> > new ones might be an alternative to carbon piles.
> 
> The OP said 200 (TWO HUNDRED) amps.
> Nothing mentioned so far comes anywhere near being capable of 200 AMPS. 
> :-?

Large variac with rectifier ?

Jamie

wanderer wrote :
> On Wednesday, May 14, 2014 7:21:42 PM UTC-4, OldGuy wrote:
>> Who makes a good stable carbon pile?
>> 
>> Stable as in it maintains its resistance as current is varied.
>> 
>> 200 amp range, 100 VDC.
>> 
>> Currently using a battery load tester but I want something I can mount 
>> 
>> on my own equipment.
>> 
>> 
>> 
>> e.g. I have DC motor that I want to voltage up to see how it draws.
>
> Look for sewing machine foot pedals. The old ones had carbon piles and the 
> new ones might be an alternative to carbon piles.

The OP said 200 (TWO HUNDRED) amps.
Nothing mentioned so far comes anywhere near being capable of 200 AMPS. 
:-?

-- 
John G

On Monday, May 19, 2014 2:08:06 PM UTC+1, Michael Terrell wrote:
> meow2222@care2.com wrote:
> > > On Thursday, May 15, 2014 12:21:42 AM UTC+1, OldGuy wrote:

> > > > Who makes a good stable carbon pile?
> > > Stable as in it maintains its resistance as current is varied.
> > > 200 amp range, 100 VDC.
> > > Currently using a battery load tester but I want something I can mount
> > > on my own equipment.
> > > e.g. I have DC motor that I want to voltage up to see how it draws.

A series lampholder might do you, just pick a filament bulb to suit.

> > > I thought carbon piles were almost a century out of date. You could always make one from the carbon rectangles in discarded 9v batteries. Surely there are easier ways to speed control a motor though.
> > > If you must do it old school, a salt water dimmer is far quicker to make. Sometimes dubbed a scariac.

>    Where are you getting 9V batteries made like that? All I've seen for
> years are made from six AAAA cells.

The ones I opened a few years ago were all stacked flat rectangle cells. No idea what types they were. I think usually they're whichever version you dont want.


NT

On Mon, 19 May 2014 09:08:06 -0400, Michael A. Terrell wrote:

> meow2222@care2.com wrote:
>> 
>> On Thursday, May 15, 2014 12:21:42 AM UTC+1, OldGuy wrote:
>> 
>> > Who makes a good stable carbon pile?
>> > Stable as in it maintains its resistance as current is varied. 200
>> > amp range, 100 VDC.
>> > Currently using a battery load tester but I want something I can
>> > mount on my own equipment.
>> > e.g. I have DC motor that I want to voltage up to see how it draws.
>> 
>> I thought carbon piles were almost a century out of date. You could
>> always make one from the carbon rectangles in discarded 9v batteries.
>> Surely there are easier ways to speed control a motor though.
>> 
>> If you must do it old school, a salt water dimmer is far quicker to
>> make. Sometimes dubbed a scariac.
>> 
>> NT
> 
> 
>    Where are you getting 9V batteries made like that? All I've seen for
> years are made from six AAAA cells.

     Carbon-zinc super heavy duty, apparently. 6 lozenges stacked. Are 
those thick black plates carbon, or compacted battery gunk? Dunno. I'll 
take a stab at putting a pic on abse.




-- 
/home/wond/Documents/sig.txt

Michael A. Terrell <mike.terrell@earthlink.net> wrote:
> 
> meow2222@care2.com wrote:
>> 
>> On Thursday, May 15, 2014 12:21:42 AM UTC+1, OldGuy wrote:
>> 
>> > Who makes a good stable carbon pile?
>> > Stable as in it maintains its resistance as current is varied.
>> > 200 amp range, 100 VDC.
>> > Currently using a battery load tester but I want something I can mount
>> > on my own equipment.
>> > e.g. I have DC motor that I want to voltage up to see how it draws.
>> 
>> I thought carbon piles were almost a century out of date. You could always make one from the carbon rectangles in discarded 9v batteries. Surely there are easier ways to speed control a motor though.
>> 
>> If you must do it old school, a salt water dimmer is far quicker to make. Sometimes dubbed a scariac.
>> 
>> NT
> 
> 
>   Where are you getting 9V batteries made like that? All I've seen for
> years are made from six AAAA cells.

those are the alkaline ones.

there's got to be a school in china still making dry cells.

On Wednesday, May 14, 2014 7:21:42 PM UTC-4, OldGuy wrote:
> Who makes a good stable carbon pile?
> 
> Stable as in it maintains its resistance as current is varied.
> 
> 200 amp range, 100 VDC.
> 
> Currently using a battery load tester but I want something I can mount 
> 
> on my own equipment.
> 
> 
> 
> e.g. I have DC motor that I want to voltage up to see how it draws.

Look for sewing machine foot pedals. The old ones had carbon piles and the new ones might be an alternative to carbon piles.

meow2222@care2.com wrote:
> 
> On Thursday, May 15, 2014 12:21:42 AM UTC+1, OldGuy wrote:
> 
> > Who makes a good stable carbon pile?
> > Stable as in it maintains its resistance as current is varied.
> > 200 amp range, 100 VDC.
> > Currently using a battery load tester but I want something I can mount
> > on my own equipment.
> > e.g. I have DC motor that I want to voltage up to see how it draws.
> 
> I thought carbon piles were almost a century out of date. You could always make one from the carbon rectangles in discarded 9v batteries. Surely there are easier ways to speed control a motor though.
> 
> If you must do it old school, a salt water dimmer is far quicker to make. Sometimes dubbed a scariac.
> 
> NT


   Where are you getting 9V batteries made like that? All I've seen for
years are made from six AAAA cells.


-- 
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

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