Kenargo, How Does It Work?

[Kengar]

Hi Kenargo,

I'm looking at this thread:
http://reefcentral.com/forums/showthread.php?s=&threadid=1534604

re using timer as per your suggestion to limit self-cleaning skimmer head to being on for just thirty seconds or so. Despite being a patent attorney, I'm not understanding how the timer would be wired up, even looking at the timer spec sheet from the timer-related web site. (Maybe that's because I don't have the actual device in front of me to play with and see how it operates.) Could you explain generally how that timer device works? If I understood that, perhaps I would "see the light" as to how it would be used to control the ultimate device itself. Maybe a sketch of how you have yours set up, if possible?

(As noted in other thread, I'm considering using a manual timer plugged into DC-8, then powering the relevant DC-8 outlet for just a 1/4 day, to get operation of the SCH once every four days. Could you perhaps explain what would get plugged into what with that in mind, too?)

Thanks VERY much for all your guidance.

Ken

[kenargo]

I'll try the text only explaination and if that doesn't work I can draw something out. Here goes...

The board is powered by a 6/12 v xformer.

When power is applied the timer circuit starts and when the timer exipres it energizes a relay (and the LED comes on). The relay has a common (C), a normally connected (NC) and a normally opened (NO) contact; what I did was to cut 1 power wire from my cleaning head and connect 1 end to C and the other to NC. When the DC8 turns on it applies power to the card and also to the cleaning head (through the relay). After the time expires the relay engages which breaks the connection to the cleaning head. 1 minute later I turn off the DC8 which turns off everything (but in reality I could leave the card powered since the relay is a 1 time event).

Does that make sense?

[Kengar]

I'm almost there. As I understand you, the board is really just a timed switch you are inserting into one conductor in the circuit. Before the relay engages, switch is closed (as you have it set up), but after certain time period -- I assume there's a capacitor and just variable resistor in there to adjust time consant -- the switch pops open. (I don't, though, follow your statement that you could leave the card powered since relay is one-time event.)

Here's where I'm a little fuzzy. You indicate that the board is powered by a 6/12 V transformer. Is that something that comes with the board? Is the SCH also powered by a transformer? THE same transformer as the board? Or is the SCH motor powered by one source and the board powered by some other source?

Is this schematic correct?

http://i224.photobucket.com/albums/dd264/Kengar/schematic.jpg

[Kengar]

I'm almost there. As I understand you, the board is really just a timed switch you are inserting into one conductor in the circuit. Before the relay engages, switch is closed (as you have it set up), but after certain time period -- I assume there's a capacitor and just variable resistor in there to adjust time consant -- the switch pops open. (I don't, though, follow your statement that you could leave the card powered since relay is one-time event.)

Here's where I'm a little fuzzy. You indicate that the board is powered by a 6/12 V transformer. Is that something that comes with the board? Is the SCH also powered by a transformer? THE same transformer as the board? Or is the SCH motor powered by one source and the board powered by some other source?

Is this schematic correct?

schematic (http://i224.photobucket.com/albums/dd264/Kengar/schematic.jpg)

[kenargo]

Yes, I think you have it. The board does not come with a power supply, you need to get one but in the case of the SCF it was 12 v so I wired the power such that it powered the board and SCF (through the NC relay contact)

[kenargo]

http://mysite.verizon.net/resoixy5/sitebuildercontent/sitebuilderpictures/SCH_Wiring.JPG

[Kengar]

thank you!

[kenargo]

http://mysite.verizon.net/resoixy5/sitebuildercontent/sitebuilderpictures/TimerCard.JPG

[goetzc]

Way off topic, but something I've always wondered about SCHs... does it just wipe the gunk off the riser into the body of the skimmer or does it somehow lift it into the cup?

[Kengar]

i think it just wipes gunk and lets it fall back into the body of the skimmer. but your idea is interesting. . . .. . you know, of course, don't you, I'm a patent attorney :) . . . . . .

[kenargo]

Mostly, yes; it just wipes the inside of the riser tube (and rinses using a little salt water) and the gunk falls off but it lands on top of the foam and gets ejected out soon after. The foam column doesn't fully collapse. If results in a skimmer more efficient unless you are in the habit of cleaning the riser tube as a clean riser tube allows the foam to form better (and higher).

I can't tell for sure other than I am getting more skimmate; BK reports an approximate 30% increase in skimmer efficiency.