Author Topic: Pulsed signal 60% more effective then strait DC  (Read 21291 times)

0 Members and 1 Guest are viewing this topic.

Online Login to see usernames

  • Administrator
  • Hero member
  • ****
  • Posts: 4441
    • water structure and science
Re: Pulsed signal 60% more effective then strait DC
« Reply #32 on: October 20, 2009, 22:34:03 pm »
A man needs multimeters.  :)
I wanted 4 similar ones for my OU tests.
So i bought 5, because 4 or 5 where the same price.

To see if they where really similar within the 1% range, i hooked them all up at once on the same PS.

Last shot is my collection.... ;)

Steve

Online Login to see usernames

  • Administrator
  • Hero member
  • ****
  • Posts: 4441
    • water structure and science
Re: Pulsed signal 60% more effective then strait DC
« Reply #33 on: October 22, 2009, 22:06:47 pm »
This circuit doesnt work with seriecells.....argggggg
The seriecell is holding too much charge and that way the coil is not working well.
Coils need to discharge to get the needed gain.
This test reduced my stock with 10 FETS......

Steve


Offline Login to see usernames

  • Jr. member
  • *
  • Posts: 25
Re: Pulsed signal 60% more effective then strait DC
« Reply #34 on: October 23, 2009, 06:35:30 am »
So, a true parallel cell would only permit you to run at around 2 volts.   Hmmm... could you pair the cell with the coil, then daisy-chain the pairs in series to drive it at a higher voltage?

Turtle

Online Login to see usernames

  • Administrator
  • Hero member
  • ****
  • Posts: 4441
    • water structure and science
Re: Pulsed signal 60% more effective then strait DC
« Reply #35 on: October 23, 2009, 15:29:54 pm »
So, a true parallel cell would only permit you to run at around 2 volts.   Hmmm... could you pair the cell with the coil, then daisy-chain the pairs in series to drive it at a higher voltage?

Turtle

Thanks Turtle,

Tonight i will try less plates and see what that brings. That will be pretty easy, because all my plates have connectors.
I also can connect some plates in parallel.

Well, lots of testing. Its fun but sometimes hard to do.

ps.

I had really strange readings with that serie setup. at a certain frequency, the ampmeter after the fet was showing zero amps and the ampmeter at the cell was showing 1 amp......uhhhhhhhhh
That was at around 150VDC input in my 60 plate cell. The coil was screaming like a pig.... :)

Steve



Offline Login to see usernames

  • Jr. member
  • *
  • Posts: 25
Re: Pulsed signal 60% more effective then strait DC
« Reply #36 on: October 23, 2009, 18:23:24 pm »
My physics prof laughed me outa the room when I mentioned using a DVM to take power readings on a pulsed cell.

It has to be calculated, for even the RMS function of a meter cannot compensate for the phase shift in power, resistive and reactive.

Mebbe that's why the goofy #s, and mebbe that's where summathese OU claims come from.

That "AIr Force PWM" document has the calculus formula around page 15, but making it work is beyond the turtle's brain

Turtle

Online Login to see usernames

  • Administrator
  • Hero member
  • ****
  • Posts: 4441
    • water structure and science
Re: Pulsed signal 60%: 25Watt GAIN = 58% OU?
« Reply #37 on: October 23, 2009, 22:26:36 pm »
Ok,

Today a good day in the lab.
I rewired the seriecell in less serie and more parallel setup.
Here are the results of the test:
Input in circuit: 20.8V by 2.06A = 43Watts
Input in cell: 17.0V by 4.0A = 68Watts
Gain: 58% = 25Watts

I measured volts with multimeters and with my RMS Scope.
Amp measured with multimeters.

The input voltage is deliverd by my variac with recitifier and big cap.
To be on the save side with measuring, i also measured ac voltage and current  on the secondairy of the variac. That was also around the 45 watts..

So, if anybody can explain why i measure 68Watts, then please stepup.Gas output is equal to 68Watts strait DC....so, the 68Watts seems to be right as well.

Steve

Offline Login to see usernames

  • 50+
  • *
  • Posts: 68
Re: Pulsed signal 60% more effective then strait DC
« Reply #38 on: October 24, 2009, 04:04:54 am »
you cant measure it like that if you have reactive components .

You need  to measure with a  wattmeter and calculate phase shift to see your true power used .





Offline Login to see usernames

  • Hero member
  • ****
  • Posts: 2387
  • Testing
Re: Pulsed signal 60% more effective then strait DC
« Reply #39 on: October 24, 2009, 07:15:49 am »
WHat about solid state DC relays for your switching?

http://www.futurlec.com/RelSS.shtml

They could handle big power, and wrap the inductor with heavier wire, mebbe?

Turtle



Hi preacher,

Those SRR's are nice toys to play with. I had some.
The trick is more to find a switch with as less resistance as possible and no sparks during switching.
The heavier wire is good. Less resistance too. Any bulky wrapped coil is killing.


Steve

No sparks during switching. Condensers are used for such a thing. And, Yikes,, Ignor the Un edited Edit.