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Quote:
Originally Posted by Holst
If you seriously believe heat is created by friction of water inside a pump to a significant degree, I suggest some reading up on electric motors . While some friction related losses do occur, this is pump related. Have a quick read, you might find the losses and efficiency part useful.
Quote:
Originally Posted by phextwin
OMG, did anyone not understand my sarcasm in this statement? I am a nuclear engineer by trade and don't need this explained to me. :stick: :p:
ok thats alot of posts to respond to.
holst I can try hooking the thing up to my rig right now and giving you temp readings with the heatercore hooked up, but I doubt it will be of much use as my cpu reads wacko temps and I do not consider motherboard/videocard onboard sensors to be useful in any testing. but with that said i will still give it a a shot and see what happens.
freecable guy, the performance increase from the 30 going from the 20 isnt 3x. BUT the heat dump IS 3x. so the two are NOT linear and thus this is a poor choice of pump.
Brandon, your 6002 will NOT like this pump. after 2.5gpm the gains has by increasing flow on the 6002 are abou ziltch. as others have said this pump is really only even remotely useful with a G4.
I do agree that there is a point where there would be enough RAD power to cool the water, but IMO its just not worth it. to cool the water enough you would proll need about 2.5-3x the rad power that you would fora MD20 or other 12volt pumps. and that is JUST to cool the water. you would also need some way to vent the hot air away from the pumps casing, which would in turn heat up the room. so there is really no way you could have this pump in your case, even with a large custom made case.
about the 50hz and 60hz thing. both pumps are using the same input voltage and wahtnot. just the pumps speed is based NOT on volts but entirely on the hz. why, i have no idea as im not an EE. so at 60hz it pumps more than at 50hz but the only increase in heat from the 60hz one is a slightly higher power draw and a little more friction. according to what cathar calculated the lower heat ouput from the 50hz (its a small amount) does not make up for the loss in flow.
Ahh!!! Stop. Thanks. :DQuote:
freecable guy, the performance increase from the 30 going from the 20 isnt 3x. BUT the heat dump IS 3x. so the two are NOT linear and thus this is a poor choice of pump.
Edit: You will actually find (discluding pump efficiency) that double the pump head requires 2.8x the power (cube-root)....
This should help...
http://www.engineersedge.com/fluid_flow/pump_laws.htm
Why the pump speed is entirely based on speed instead of voltage?Quote:
Originally Posted by MaxxxRacer
I'd say that's because internal electrics convert different amounts of voltage in the same amount of power.
Though why 60Hz and 50Hz dump the same amount of wattage confuses me.
While I'm probably completely wrong, if I'd have to make a simple guess I'd say that both input and output would increase from 50Hz to 60Hz by 60/50=1.2.
Iwaki's specs confirm my error. While some of the input voltages' ratio are very close to 1.2 (like the MD-15 and MD-20 series), too many aren't.
Ahhh! (again) Speed of the pump is based on frequency. Pumping power is based on voltage (actually, this is a measurement of apparent power). Seriously though, read the URL that I posted...it covers the *basics*.Quote:
Why the pump speed is entirely based on speed instead of voltage?
I'd say that's because internal electrics convert different amounts of voltage in the same amount of power.
-FCG
I know that. F=1/T.Quote:
Originally Posted by freecableguy
But you're right, I said it wrong.
I mean I think the internal electronics prevent the pump from running faster at higher voltages.
Edit: Though I will read that link when I have time. I think it does contain a lot of information I do not know yet.
Yes, frequency is the inverse of the period...this is just a mathematical definition.
Let’s begin the discussion by describing what causes an AC induction motor to run at a particular speed. Every AC induction motor has poles, just like a magnet. Unlike a simple magnet, these poles are formed by bundles of magnet wire (called windings) wound together in slots of the stator core. In most cases, you can look inside the motor and count the number of poles in the winding: they are distinct bundles of wire, evenly spaced around the stator core.
The number of poles, combined with the alternating current line frequency (HZ), are all that determine the no-load revolutions per minute (RPM) of the motor. So all four-pole motors will run at the same speed under no-load conditions, all six-pole motors will run at the same speed, and so on.
The mathematical formula to remember in helping make these calculation is the number of cycles (HZ) times 60 (for seconds in a minute) times two (for the positive and negative pulses in the cycle) divided by the number of poles.
f*120/n = speed of the AC motor (the pump)
So, we can see that a 50Hz motor will spin at a lower speed than a 60hz motor, once again, assuming no load.
I'm gonna try putting heatsinks all over my pump and I mean ALL OVER. :D
Sorry if I'm making a stupid comment, but that doesn't explain my earlier reaction in which I said it seems impossible to dump the same amount of heat at different voltages, right?
One critical relationship between line frequency and magnetic devices is efficiency. The physics of electric circuits tells us that AC magnetic devices increase in efficiency as line frequency increases. Sounds simple, doesn’t it? Just build your power systems and devices to the highest frequency possible. Not so fast. Another physical characteristic to keep in mind is that current flow in a conductor tends to be closer to the surface of the conductor as frequency increases. So as the frequency goes up, solid conductors begin to resemble hollow pipes as the electrons making up the current flow migrate to the outer surfaces of the conductors.
At these higher frequencies, the energy of the electrons has a tendency to actually leave the surface of the conductor. A common example of this principle in action is radio transmission. As the frequencies get higher, all of the energy can be made to leave the conductor in a form of energy called radio waves. This also helps explain why overhead power lines tend to interfere with radio reception (the annoying 60-cycle hum). What you are hearing is energy loss from the power lines becoming a radio wave that is intercepted by the radio receiver.
Consequently, the designers of electrical devices must strike a balance: the desire to use higher frequencies to improve the efficiency of converting electrical power to mechanical work and the need for lower frequencies to keep power from escaping the conductor as radio waves.
So the evolution of 50 and 60 hertz systems developed as a result of this need for balance, with additional influences coming from politics and geographic considerations. North America and other regions struck the balance at 60 hertz, while Europe settled on 50 hertz. Who’s right?
You probably realize by now that frequency is a parameter for motor selection and application. What you may not realize is that a motor designed to operate at the lower 50 hertz frequency may operate in a satisfactory manner at 60 hertz, at least from an efficiency and heat loss standpoint. This is because a 50 hertz motor contains added material to make up for the modestly decreased efficiency found at the lower line frequency. But keep in mind that when going from 50 to 60 hertz, the motor’s speed will increase proportionately to the increase in frequency (60/50=6/5=120 percent).
now there is a man who knows his motors!
thanks for the lesson FCG.
thanks for the link too. helpful info.
Its called the skin effect. Its pretty much irrelevent though for power circuits. You have to be in the khz range before its even noticable.Quote:
One critical relationship between line frequency and magnetic devices is efficiency. The physics of electric circuits tells us that AC magnetic devices increase in efficiency as line frequency increases. Sounds simple, doesn’t it? Just build your power systems and devices to the highest frequency possible. Not so fast. Another physical characteristic to keep in mind is that current flow in a conductor tends to be closer to the surface of the conductor as frequency increases. So as the frequency goes up, solid conductors begin to resemble hollow pipes as the electrons making up the current flow migrate to the outer surfaces of the conductors.
The 60Hz hum is NOT radio. Its simple induction. A 60Hz radio wave would have a wavelength of about 5000km. Thats a substantial fraction of the Earth's width. You're not going to generate meaningful radio energy at anything within a few orders of magnitude of a 60Hz circuit. Thats why most stuff is at Mega and GigaHertz (though AM is in the upper KHz range).Quote:
At these higher frequencies, the energy of the electrons has a tendency to actually leave the surface of the conductor. A common example of this principle in action is radio transmission. As the frequencies get higher, all of the energy can be made to leave the conductor in a form of energy called radio waves. This also helps explain why overhead power lines tend to interfere with radio reception (the annoying 60-cycle hum). What you are hearing is energy loss from the power lines becoming a radio wave that is intercepted by the radio receiver.
Thats not right. 60Hz was chosen by tesla because it was the lowest frequency that did not flicker visably in an incandsant bulb (think 60 fps in games). No one knows where 50Hz came from, but probably much the same reasoning as 60Hz. The frequency does not effect the effciency of the power distribution system (well unless you're at extremes), although low frequencies are a little easier to work with since induction is less of a problem at low frequencies. If they'd put it too high then you'd lowpass out your AC signal due to LR filter effects in the lines. OTOH go too low and transformers become more expensive. None of this effects effciency though.Quote:
Consequently, the designers of electrical devices must strike a balance: the desire to use higher frequencies to improve the efficiency of converting electrical power to mechanical work and the need for lower frequencies to keep power from escaping the conductor as radio waves.
So the evolution of 50 and 60 hertz systems developed as a result of this need for balance, with additional influences coming from politics and geographic considerations. North America and other regions struck the balance at 60 hertz, while Europe settled on 50 hertz. Who’s right?
More info: http://en.wikipedia.org/wiki/Alternating_current
Try again.Quote:
None of this effects effciency though.
Well out of curiosity i stuck the pump on my test setup.
the radiator outlet temp with the 50Z was 78.5F and with the MD30 it was 83.2F with all other things being equal.
I should also note that the MD30 raised the ambient temp some. not sure on the exact numbers as i didnt document it, but it dumps a noticeable amount of heat into the air through the casing.
the radiator i used was the PA160 with a TT thunderblade fan at 12volts. I am gonna retest the md30 with both a BIX2 and 2-199 heatercore with denkis at 12volts on both to see if i cant get the temps back down again. I will wait a while though as i need to get the room temp back down a C or so.
We haven't even gotten to talking about voltage, current, armature/field current and resistance, slippage and torque...of course all of this leads to what you really care about, work, power, energy and heat output (overall efficiency).
another minor update here. it seems the water temp is varying between the previosuly said 83.2 and 84.3. it slowly swings back and forth between them. might have somethign to do with the cpu, but im not sure. i checked ambient between the two temps and it was within .3F so there is no issue there.
wel right now the ambient temp is 72.1F and the water temp is at 75.6F right now. here is how i did it.
i need help you say? ya ur probably right ;)
http://www.xtremesystems.org/forums/...id=34228&stc=1
lol... you know you can avoid all the radiators and fans and stuff just by hooking up your loop to your faucet and putting the output hose into the sink... a lot of apartment/condo's have WATER BILL built into the rent... check it out ;)
Tap water runs a constant 15C in most areas!!
C
insulation then comes to mind....
no insulation neded FGC. my room temp is around 20-22C.
charlie i thought of that. the head pressure on the fauciet is amazing too. you would get around 4-5GPM with it. but the problem arrises of draping large 5/8ID tubing from the faucet to my room and my mom killing me. or in your case your wife killing you.
insulation need, i mean, if you use 15C faucet water...
i know what u meant. but the water temp would be a feeble 5-7C below ambient. with the relatively how humidity in los angeles it wouldnt get condensation.
mount a series of small aluminum heatsinks (like the cheap ones from radio shack) to the pump housing with thermal epoxy after etching the finish off of those sections of the pump housing -- then, add a low airflow (close to silent) 92mm or 120mm fan directly behind the pump. The temp difference might surprise you. ;)
it has worked with other pumps of a like design anyway...
ya its something to consider rod, but even if you do that you need to remove the heat out of the case...
we've been doing that for a long time, dont think its going to be a problem max ;)
A length of copper corrugated pipe on the outlet of the pump may make up for some of the increased heat.