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Need help from electrical guru's.

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February 28, 2002 3:29:14 PM

First of all, what I'm trying to do is to put together an external watercooling system where the radiator/pump/reservoir are in a seperate case. Unfortunately, I can't use the power supply to power the pump and fan in this setup. My question is how do I wire this rig with an on/off switch that has only one AC power cord powering the system?

Correct me if I'm wrong, do I just get an extension cord and splice on a power switch in series, and then just run a splitter for the pump and fan(AC).

Also, how would I wire the AC fan (bare wire)? Do I have to use something like a terminal/fuse block?

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March 1, 2002 6:29:54 AM

First of all, don't get in over your head and burn the house down.
Second, are you sure the fan and pump are 110V AC and not 12V? If the fan and pump are actually 110V I would use a fuse or a circuit breaker of some type. Check out a hardware store. Something like <A HREF="http://www.grainger.com/Grainger/productdetail.jsp?xi=x..." target="_new"> this</A> with <A HREF="http://www.cornerhardware.com/hardware/iteminfo.html?ac..." target="_new">fuse</A> might work (with an outlet instead of the switch) but something more for indoor whould be easier to work with.
As far as getting 110v to the second case I first check the back of your computer on the power supply. Some (my new comp doesn't) have an opposite power cord type connection on them. They make a power cord for this that usually is used to connect to a monitor instead of requiring two separate cords plugged into a wall. You could use this for your case with the watercooling equip. On older AT cases the power switch on the comp turns this on/off too. On newer ATX stuff I'm not sure but the switch on the back of the PS might do the same. Remember on ATX stuff there is always power to the motherboard unless this switch is off. If your watercooling is 12V connect this cord to an old PS or if it is 110V cut the end off and use it to connect to your fuse setup. This might give you some ideas. Give me more info.
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March 1, 2002 2:29:44 PM

I posted this one first, but when it quickly reached the second page, so I thought it was a dumb question so I just put a copy in the Cooling section.

Okay, here's the complete scoop of my water cooling plans. I'll be using an EHEIM water pump (110vAC), hobby fuel tank(used as a reservoir), an off the shelf radiator w/120mm AC Fan (110/120vAC also), all connected to a Maze waterblock inside my computer. The pump, radiator, and fan are going in a seperate enclosed box. Instead of having 2 ac cords coming out(pump and fan), I want to wire it so that I have just one cord. I also want a way to manually turn the pump/fan off so it doesn't run 24/7 and that I don't have to get off my lazy arse to unplug it. This means I have to wire up some type of an ON/OFF switch. How do I go about doing this?

I believe I understand what you are saying, but I'm not to savvy when it comes to electrical wiring and I don't want to electrocute my self because the whole thing is wired wrong.
March 2, 2002 12:38:58 AM

I assume your comp is an ATX board. See if it has the plug I was talking about on the back of the power supply.
I'm not sure but maybe ATX systems don't have this anymore (mine doesn't) but this switches on/off with the power switch on the comp on an old AT anyway. Also check the fan and the pump for amperage ratings (or watts if they don't list that). A relay might be required if the new ATX's don't have that plug anymore. I will see if I can find something on the web that would work.
March 2, 2002 5:55:34 AM

Well, I remember my other computers having that extra plug, but I don't see it anywhere on my current enermax psu.

I'll be using an EHEIM 1250 pump that is rated to consume 28Watts or an EHEIM 1060 that is rated at 50watts. I don't know about the fan yet but I believe a generic ac fan uses about .20A.

On a sidenote, what exactly is a relay? and why would I need one? I've seen some 120v AC power relays but I just don't get exactly what they do and what all the terminology means such as Double-Pole, Double-Throw(DPDT) or Single-Pole, Single-Throw(SPST) and H/P ratings they give with each relay. I guess I'm a complete idiot when it comes to these type of things.

I think I'm making it more complicated than it really is...
March 3, 2002 6:57:29 AM

A relay is like a power switch in this case. They can be used for much more that. A diagram would explain it better. In your case a 12V DC signal could be use to turn a 120V AC switch on/off. The currenct required to "throw the switch" is very very small but the load on the 120V side can be large 10-30A depending on the ratings plus they are totally isolated from each other. (ie. the headlight switch on your car is probaby rated for milliamps but it triggers a relay that is rated for 30-50 amps the current required for the headlights.) In your case a 12V signal on your computer could switch the 120V for your watercooling on/off. SPST is sufficent for every case I've mentioned so far. The solenoid on your car starter is like a relay too. Otherwise wires going to your ignition switch on the dash would be about 3/4" in diameter. LOL. I found a site that should <A HREF="http://www.british-cars.org.uk/kimber/electrical/Relays..." target="_new">help</A>. Your can see the DT adds the NC/NO(normally closed/open) positions. SPDT is very common and could be used as SPST (you just don't use the NC terminal). DP just means one signal voltage (coil) throws 2 separate switches at the same time(ie. 12v signal switches a 120V pump and a 12V case fan). That site is pretty good better than me at explaining(ignore the ISO stuff). Pictures at the bottom of the page.
March 3, 2002 7:56:02 AM

Your 12V signal could come from your unused CPU fan output on your m/b (find a plug off an old fan) and run it to your coil on your relay. A SPST would work but a SPDT is probably easier to find. Make sure it is rated for at least 5A/120VAC with a 12VDC coil (some have 120VAC coils) which most are more than that. Your load will be <1 amp anyway. Connect the common to the 120V and the NO to your pump and fan. As far were to mount all this. Are you using an extra PC case to house the watercooling stuff? If yes I would find an old burnt out PS from a friend or comp store and remove the little board from the inside of it. That way you could use a standard power cord and everything would be grounded too. A 1 amp fuse would protect it. Secure the relay down and fuse holder down to the bottom of the PS box. Hell I have enough stuff around to make it for you.
March 3, 2002 8:12:33 AM

I like this <A HREF="http://www.idec.com/usa/html/RelayTimerSockets_RH.html" target="_new">type</A>. No soldiering necessary since they have screw <A HREF="http://www.idec.com/usa/html/RelayTimerSockets_DINRAIL...." target="_new">terminals</A> This <A HREF="http://www.mectronic.com/scripts/mfgpartlist.asp" target="_new">Newark</A> is a local store for me but you probably can order online too. Radio Shack should have too but I don't like the soldier type and they didn't have the screw type last time I checked.
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