Need someone good with math involving watts and amps

[Creekin]

my wife said if i say i need to buy one more she's slapping me. Lol picked up a nxzt LXE.

sounds like your revealing a bit TMI about your personal life MD,
like a bit of slap and tickle eh?

p.s. that was a Joke mate

[Utnorris]

Well, I think I am going to try and see if the Theoretical load capabilities of the TMS200 are correct, worse case is MD sends me one of his extra fan controllers, .

[Creekin]

please video it so we can all enjoy the fireworks!

[MagisD]

Only spares i have is a half burnt out kaze master and a fc-2 revision 1 with first port blown.

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[skeyo]

shush, Creekin made fun of a dude who should've used 5min on google. Case closed.

Bud take it easy. It's not that easy to calculate. Every fan has peak current when is turned on so that's why it's uses more power. So you can easy burn your fan controller. Most of controllers have over current protection but for 24/7 use sometimes is not good to use them on their limits. So there is no reason for anger.

[Diverge]

Bud take it easy. It's not that easy to calculate. Every fan has peak current when is turned on so that's why it's uses more power. So you can easy burn your fan controller. Most of controllers have over current protection but for 24/7 use sometimes is not good to use them on their limits. So there is no reason for anger.

His fan controller probably has a peak current rating as well. Look at the datasheet of any power transistor or fet. they have peak ratings as well.

If the OP wants to get technical, try to find out the transistor/fet that is used for the each channel of his fan controller, and find the datasheet. The fan controller manufacturer might just underrate their max current rating. never know, unless you look at a datasheet ;p

[OldChap]

The way I was taught...

W= Power (Watts)
I= Current (Amperage)
V= Electromotive Force (Voltage)
R= Resistance (ohms)

W
_________
I * V

W = I*V
W/I = V
W/V = I

then there was the resistance triangle too

V
_________
I * R

V = I * R
V/I = R
V/R = I

Over the years here in UK they have messed with the education system loads
It would not surprise me if this kind of info is missed off the curriculum entirely

Just by the way all you FAN boys ...when you put a fan in open air it will pull a lower current than when you put it on a rad. If you want to demonstrate this lay your fan on the bench blowing down and measure the current then do the same standing the fan in free air. Ok so it is not huge but it is different just the same...The higher the density of rad finnage the higher the current will creep

Anyone know if there is a mod for the original Lamptron fc2 to stop the induced motor noise?

[Waterlogged]

Anyone know if there is a mod for the original Lamptron fc2 to stop the induced motor noise?

Hammer?

[Utnorris]

Ok, so just for the record, I did not take any offense, hence my response, I can give as well as take unless it gets personal and then I hit the "ignore" button. It was not my intention to start a flame war, just ask a simple question. Yes, I could have just relied on Google, however I like to get more info than what is posted by who knows on the internet. I had two conflicting sources of info, so i wanted to verify, no need to have a fire even if the system is water cooled, not my idea of fun.

Anyway, I have gone back to what I was doing previously and running 6 of the San Ace fans off the Koolance controller and 3 off a 5v converter board. Not what I wanted to do, but i can't seem to find a decent fan controller for 18 San Ace fans.

Anyway, this thread looks like it should be closed based on the comments. For those that gave advice, thank you, for those that did not, it's ok, no harm, no foul.

[fgw]

Anyway, I have gone back to what I was doing previously and running 6 of the San Ace fans off the Koolance controller and 3 off a 5v converter board. Not what I wanted to do, but i can't seem to find a decent fan controller for 18 San Ace fans.

which san ace are u talking about, 9G1212H101?

took currentreadings from martinm's tests again and come to a max power dissipation of less than 1W for this san ace! dont think this is a real problem for a correct constructed fan controller .

i need a fancontroller for my build anyway. so i will build one for sure!

would recommend you run the system as described for now. may be i come up with a solution within the next two month. otherwise you can still look after a fancontroller with the requested capabilities after this time.

pm me if you have further questions ...

[Creekin]

i doubt you will find any one controller that can run 18 fans, why not just use 2 fc5's or something?

do u need to control them? if not just hard wire the lot

[OldChap]

SWC, among others, sell a rheostat (variable resistor) or two that might just do the trick for a lot of fans (probably not all 18 though) and do it the old fashioned way by inserting resistance in the circuit. This will dissipate power too so might be best mounted in a position where there is airflow but I would venture that for your immediate needs, Ut, it would resolve the problem. Big (high power) versions have little use these days though and will therefore be less common and more expensive....probably $30 or more

[Utnorris]

The only one I have found was the FC-2 that does over 30 watts per channel. Assuming the calculator I used is correct, I need 6 watts per fan, which comes out to 108 watts, however that would be on one channel and I figured I could run 6 per channel on the FC-2, so that would be ok. The problem is the whine it produces. They did redesign it with digital vrm's, however it's hard to tell who has the new one and who has the old one and even then there is no guarantee it won't make the same whining noise with 18 fans connected to it. I could do two controllers, which I may end up doing, but I was trying to keep it simple. I would just hard wire them all at 5v, but I would rather have the ability to adjust the voltages. Anyway, any suggestions would be welcomed.

[terramir]

45 W per channel would be 45/12=3.75 amps, however I got to warn you if your running at max draw your going to be running into problems of a different sort, you'll be creating heat!
Also I assume this controller uses some sort of digital PWM to control the fans and yes that can cause a whine if it's not properly capacitor'ed at the output. ( properly sized capacitor and a diode to prevent chargebacks into the controller is a must for any fan controller that wants to avoid the whine factor. Zahlman fan controllers used a method that created alot of heat but avoided the whine (this was the first commercial single fan controller) that allowed tach signal pass through.
the start-up factor could also be alleviated by using a smoothing capacitor. however if 45W is the max per channel you should use no more than about half of that for daily use (i.e. no more than 4 fans per channel and that is pushing it)
the problem with fan controllers is that they tend to design them to spec, to save money hence they usually dun spend the extra money for a good really oversize smoothing cap.
so some noise tends to get through.
just one question though WTF do you need 18 fans I'm right now designing a new case and it will have 5 fans 3 in the water cooling compartment, two in the main board compartment.
there comes a time when more fans are overkill.
Directed airflow would get you better results.
well good luck
terramir

[Utnorris]

Why 18 fans? Because I have 60 or so San Ace fans sitting around and figured why not. And this is xtremesystems, so there is no such thing as overkill.

[terramir]

Why 18 fans? Because I have 60 or so San Ace fans sitting around and figured why not. And this is xtremesystems, so there is no such thing as overkill.

Ehhh are those the 127x38 fans or the 120x25 ? aluminum frame or plastic?
these are like classics if there the ones I'm thinking of.
I could use five or six for a project if they are the ones I'm thinking of
terramir

[Creekin]

ok, so better question then
WhyTF do you have 60 fans!??!?!

and more importantly..
SHARE ya bastard!

why not use all 60?

[Martinm210]

FYI, You might consider some sort of PWM controller option instead. I haven't tested it yet, because I can't figure out how to run one without a computer, but according to Bing on OCN, PWM is better for the big fans for reducing motor noise. You might check with the gurus over at crystalfontz, their forums are generally pretty helpful.

[Utnorris]

They are 120x38mm, model 109r1212h1011, the ones they do not make anymore.

[terramir]

They are 120x38mm, model 109r1212h1011, the ones they do not make anymore.

Hmm you willing to part with 6 of them and well how much for the 6 PM me please
terramir

[MagisD]

Isn't the new fc-t pwm?

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[Martinm210]

Isn't the new fc-t pwm?

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That's what we heard, but after watching this video, @3:33 it clearly show Voltage as an indicator option.

PWM doesn't operate at lower voltage, so I'm lost... As far as I can tell it's voltage controlled.

[terramir]

That's what we heard, but after watching this video, @3:33 it clearly show Voltage as an indicator option.

PWM doesn't operate at lower voltage, so I'm lost... As far as I can tell it's voltage controlled.

Actually PWM does operate @ a lower voltage (not really but bear with me)
what PWM does is either switch it on or off so on the axis of time you have a bunch of 12 states and a bunch of 0 volt states, now if you capacitor filter that output sufficiently Before the capacitor you will see a bunch of 12V states and a bunch of 0V states, but on the other side of the circuit where the filter capacitor is you will see an average voltage that can be anywhere from 0 to 12V.
Let's say the 12V is on 75% of the time hence 0V is on 25% then the voltage after the filter capacitor should be around 9V if you use a filter cap that is too small you will get spikes in that voltage (that's where the humming comes from in some pwm controlled fans). Now let's say 12V is on 66.6% of the time then you'll get about 8V after the filter I think you see where I'm going with this.
So while the PWM circuit IS a 12V circuit because of the charging curve of a capacitor the voltage that is output is lower than 12V, there is also another danger, if you design the filter capacitor to high then it will take a long time for the voltage desired to be reached, however; unless you use one that is way over sized the delay should be no more than a few seconds. There is a way around that though. You measure the voltage after the filter cap and base the on off cycles on this voltage. So it will start basically always on till it reached the desired voltage.
terramir

[Martinm210]

Actually PWM does operate @ a lower voltage (not really but bear with me)
what PWM does is either switch it on or off so on the axis of time you have a bunch of 12 states and a bunch of 0 volt states, now if you capacitor filter that output sufficiently Before the capacitor you will see a bunch of 12V states and a bunch of 0V states, but on the other side of the circuit where the filter capacitor is you will see an average voltage that can be anywhere from 0 to 12V.
Let's say the 12V is on 75% of the time hence 0V is on 25% then the voltage after the filter capacitor should be around 9V if you use a filter cap that is too small you will get spikes in that voltage (that's where the humming comes from in some pwm controlled fans). Now let's say 12V is on 66.6% of the time then you'll get about 8V after the filter I think you see where I'm going with this.
So while the PWM circuit IS a 12V circuit because of the charging curve of a capacitor the voltage that is output is lower than 12V, there is also another danger, if you design the filter capacitor to high then it will take a long time for the voltage desired to be reached, however; unless you use one that is way over sized the delay should be no more than a few seconds. There is a way around that though. You measure the voltage after the filter cap and base the on off cycles on this voltage. So it will start basically always on till it reached the desired voltage.
terramir

Interesting, thanks for sharing

So, in essence, the fan will see voltage control, but the controller is converting 12V to a lower voltage through PWM + Capacitor?

The advantage of this is simply not generating heat in the controller?

Sorry for the dumb questions, just trying to get at least a little pinky around the topic. I've had a few people indicate on my 38mm fan tests that the problem is lower voltage, and PWM is the better way to go....yet it sounds like this controller is converting PWM to lower voltage. Why not leave it PWM if PWM is better?

[Church]

Why not leave it PWM if PWM is better?

Because some analogue, not pwm fans might get extra noise under pwm regulation. IIRC In normal 4pin pwm fan there is separate wire for pwm synchronisation, that solves that issue, but with analogue fan with normal 3pin these voltage spikes might differ at different rpm at which point coils should actually charge and push to turn rotor and at one position have more voltage, at different less, so possibly resulting in that extra noise.
Otherwise pwm of course is better then analogue regulation in several ways - it's circuitry is cheaper, as doesn't require monstrous heatsinks to dissipate redundant power, it can handle much higher current, with pwm minimum rpm-s can be lower (as less of a problem minimum startup voltage to start turn motor, because it's always full 12V or 0V). But probably because that pwm rpm regulation is newer, and many analogue fans/pumps exist, some choose analogue regulation as safe bet for everything. (eg. Aquaero).