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ehsjr electronics forum Guru
Joined: 03 May 2005
Posts: 863
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Posted: Tue Aug 22, 2006 3:50 pm Post subject:
Re: Will this DC motor control work?
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Eric R Snow wrote:
| Quote: | Greetings All,
I have been trying all sorts of designs out in my head for
controlling wire feed speed. The goal is to have a push-pull wire feed
system in a small MIG welder. The pulling wheels should try to spin
just a little faster than the push wheels to keep the wire taught. I'm
thinking about 5% difference but with a slip clutch on the pull wheel.
The slip clutch will be adjusted so that it slips before the wheel
slips on the wire. I have built and tested the clutch and it works
well.
My latest plan is to use wheels spinning at identical speeds with
the pulling wheels being 5% larger in diameter. To keep the wheels
spinning the same a tach would be driven by the idler push wheel and
the output used to control the pull driver wheel.
By using the push idler wheel as the speed reference even if the
push drive wheel slips on the wire the idler wheel should not slip.
I think I've got the mechanical part figured out. However, does
this sound like a good plan electronically?
Thanks,
Eric R Snow
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Belt or gear drive both wheels from a single motor.
Forget the electronics - not needed if you do that.
Ed |
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simo.kaltiainen@sunpoint. electronics forum addict
Joined: 20 Mar 2006
Posts: 51
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Posted: Tue Aug 22, 2006 3:55 pm Post subject:
Re: Just a question
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Tim Williams wrote:
| Quote: | Voltage doesn't matter if the output is in fact more like constant current
(or current limited). In that case, voltage will rise to whatever it
ultimately wants to.
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Yes, if it's constan current or current limited, but if it's a constant
voltage charging (like lead batteries usually), I was actually still
wrong, as it's not the effective voltage even then that matters. But
it's the effective time, which is increased by the cap (without filter
cap the battery gets charged only at the peaks of the pulsating
voltage, but with a filter cap added, it makes the voltage steady,
charging the battery all the time). |
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quanghoc@gmail.com electronics forum beginner
Joined: 14 Aug 2006
Posts: 13
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Posted: Tue Aug 22, 2006 4:28 pm Post subject:
Adjustable Carbon Attenuator
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I looked at this Attenuator:
http://www.vishay.com/docs/32025/m2001h.pdf
And there are some specification I don't understand. So what is
Resistive Element? I wonder if it is always "Carbon on laminated
paper"!!? If so, why they put it in there? Same question to Wiper
Contact.. isn't it always "Metal"??
Thanks. |
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