3 san ace's to one channel of Sunbeam Rheobus Extreme ?

[andressergio]

Guys

I connected my 3 San Ace's to one channel of the 6 of 30W that the Sunbeam Rheobus Extreme can handle, but touching the heatsink of the channel after some mins it's really hot, can't even put my finger on it, i have them regulated at 6,5V and over it there's a DVD burner, is that ok ? is normal or should connect each fan to each channel ?

Cheers
Sergio

[fornowagain]

I have 3 on one channel, had to put a small 40mm fan on it to keep it happy.

[andressergio]

I have 3 on one channel, had to put a small 40mm fan on it to keep it happy.

LOL, so if no fan ? maybe i blow a channel ?

Cheers :up:

[fornowagain]

You may have a bit more headroom on the extreme, mine is the 4 channel and got too hot for my liking.

http://img159.imageshack.us/img159/5316/dscf2707si1.jpg (http://imageshack.us)

But I do now have 6 fans and 2 DDC Ultra pumps on it and it doesn't even get warm now.

[Utnorris]

I run the 4 channel model and I have 2 San Aces on the 1st channel, 3 on the second and 2 on the third. No issues and I even stuck my finger on the heatsink and it didn't get burned. This was after playing games for awhile so I had the controller turned up to a little over 3 quarters of the way. It is possible you got one of the first units that had issues with heat, but I am pretty sure that was fixed, hence the sinks are attached better. The rating on the 4 channel is roughly 1.67 amps which is well within 3 San Ace fans pull. If you think it is getting too hot, put a small 60mm fan down there to help cool it, but I don't think it is needed.

[NaeKuh]

Guys

I connected my 3 San Ace's to one channel of the 6 of 30W that the Sunbeam Rheobus Extreme can handle, but touching the heatsink of the channel after some mins it's really hot, can't even put my finger on it, i have them regulated at 6,5V and over it there's a DVD burner, is that ok ? is normal or should connect each fan to each channel ?

Cheers
Sergio

heres how you calculate wattage. Its really easy.

The psu will be supplying 12V.

Then each san ace is .53Amps.

Amps x Volts = Watts.


So you got 12V x .53Amps = 22.64W x 3 = Say Bye Bye RheoBus.

Wanna still argue? Okey lets say you downvolted it, cuz your a smart ass, :P

7V x .53Amps = 13.20W x 3 per channel = 39.6W which your still majorly pushing it. You turn it to 12V and its bye bye rheobus. :rofl:

[WhiteFireDragon]

So you got 12V x .53Amps = 22.64W x 3 = Say Bye Bye RheoBus.



actually you did that wrong, and i can tell even without pulling out a calculator. how can each fan be over 12watts if each one runs less than 1 amps? if you have a crazy san ace that does 1amp at the full 12v, that's only 12watts. and knowing that each fan actually can only draw about half this much, you'd expect each fan to use up less than 7watts, so you can take up to 4 fans max per channel

[Waterlogged]

I need to also point out that fan controllers don't start getting warm until you under volt the fan(s). The higher the load and the more you under volt, the hotter it will become.

[fornowagain]

So you got 12V x .53Amps = 22.64W x 3 = Say Bye Bye RheoBus.

Just a typo I'm sure, its 12 x 0.53 x 3 = 19.08W

[axis]

Just a typo I'm sure, its 12 x 0.53 x 3 = 19.08W

Which is WELL below the 2.5A/30W per channel that the 6 channel Sunbeam can do.

Axis

[.Logic]

Yea, NaeKuh just made a mistake...

3 on a channel running at 12V is absolutely fine, at 6.5V you could put 7 or 8 on the controller and not have a worry in the world.

[septim]

this is good to know in advance...

[NaeKuh]

actually you did that wrong, and i can tell even without pulling out a calculator. how can each fan be over 12watts if each one runs less than 1 amps? if you have a crazy san ace that does 1amp at the full 12v, that's only 12watts. and knowing that each fan actually can only draw about half this much, you'd expect each fan to use up less than 7watts, so you can take up to 4 fans max per channel

oh shiet... sorry.

:rofl:

my Windows calc. must of been tripping. After i got value i just pressed paste. :P

[Zeus]

I need to also point out that fan controllers don't start getting warm until you under volt the fan(s). The higher the load and the more you under volt, the hotter it will become.

True, my Zalman fancontroller's front feels warm with 2 SanAce 120mm fans hooked up to it (1 per channel) but only with the voltage turned down.

Soon as i run 'm full speed (breaking out the earplugs) the fancontroller feels cool to the touch.

[andressergio]

Well guys I apreciatte your help very much, and YES it turns hot when undervolting...i will have to figure out then if i put a fan or just put each one on a channel, that sux but well...

Thank you for pics and calculations ;)

Cheers
Sergio

[andressergio]

I run the 4 channel model and I have 2 San Aces on the 1st channel, 3 on the second and 2 on the third. No issues and I even stuck my finger on the heatsink and it didn't get burned. This was after playing games for awhile so I had the controller turned up to a little over 3 quarters of the way. It is possible you got one of the first units that had issues with heat, but I am pretty sure that was fixed, hence the sinks are attached better. The rating on the 4 channel is roughly 1.67 amps which is well within 3 San Ace fans pull. If you think it is getting too hot, put a small 60mm fan down there to help cool it, but I don't think it is needed.

Thanks Utnorris but i received latest batch from petra's...but yesterday testing it i can't maintain my finger over it for a seconds...runing the 3 san ace's at 6,5V...and i tested outside

Cheers
Sergio

[andressergio]

You may have a bit more headroom on the extreme, mine is the 4 channel and got too hot for my liking.

http://img159.imageshack.us/img159/5316/dscf2707si1.jpg (http://imageshack.us)

But I do now have 6 fans and 2 DDC Ultra pumps on it and it doesn't even get warm now.

Thanks for the pic mate :up:

[andressergio]

heres how you calculate wattage. Its really easy.

The psu will be supplying 12V.

Then each san ace is .53Amps.

Amps x Volts = Watts.


So you got 12V x .53Amps = 22.64W x 3 = Say Bye Bye RheoBus.

Wanna still argue? Okey lets say you downvolted it, cuz your a smart ass, :P

7V x .53Amps = 13.20W x 3 per channel = 39.6W which your still majorly pushing it. You turn it to 12V and its bye bye rheobus. :rofl:

LOL you called my smart ass :D and you did the wrong maths :rofl:

just kiddin' thank for taking the time doing it

Cheers
Sergio

[andressergio]

I run the 4 channel model and I have 2 San Aces on the 1st channel, 3 on the second and 2 on the third. No issues and I even stuck my finger on the heatsink and it didn't get burned. This was after playing games for awhile so I had the controller turned up to a little over 3 quarters of the way. It is possible you got one of the first units that had issues with heat, but I am pretty sure that was fixed, hence the sinks are attached better. The rating on the 4 channel is roughly 1.67 amps which is well within 3 San Ace fans pull. If you think it is getting too hot, put a small 60mm fan down there to help cool it, but I don't think it is needed.

Utnorris

as far as i concerned 3 fans running at 12V will consume 3 x 0,52A = 1,52A, BUT undervolted to 6,5 will be more...as resistance is increased to get them to 6,5 , intesity goes up...is this correct ?

Cheers mate
Sergio

[Blazing fire]

V = IR
12V = .52A X R
R = ~23ohms

I = V/R
I = 6V/23ohms
I ~ 0.2608A

For 12v, each fan draws .52A but at 6v, each fan draw ~0.2608A. I think it is right. Could someone confirm my mathematics please?

[andressergio]

V = IR
12V = .52A X R
R = ~23ohms

I = V/R
I = 6V/23ohms
I ~ 0.2608A

For 12v, each fan draws .52A but at 6v, each fan draw ~0.2608A. I think it is right. Could someone confirm my mathematics please?

Nope i just called a technician and told me that each fan REGULATED TO 6V will consume aprox 1A so it'll have to handle 3A on each channel and that's i think that from the specs of the transistor on each channel handles less than than and the main reason for overheat damn...:mad: Of course 3 at 12V non regulated will consume 0,52 x 3

[Blazing fire]

Forgot to mention. It may not follow ohm's law.

[jc99]

Yeah, that's .53 amps @ 12V. Lower the voltage and your current draw will change from the rating written on the fan. The fan also isn't a fixed resistor in calculations. Just measure the dc resistance across the terminals. You'll get close to 0 ohms. Obviously it's not a short when you hook it up to the PSU so some of that 'resistance' is inductive in nature.

[andressergio]

Yeah, that's .53 amps @ 12V. Lower the voltage and your current draw will change from the rating written on the fan. The fan also isn't a fixed resistor in calculations. Just measure the dc resistance across the terminals. You'll get close to 0 ohms. Obviously it's not a short when you hook it up to the PSU so some of that 'resistance' is inductive in nature.

So it's more or less what i say, I think I'll kill it if i hook the 3 san aces on one channel regulated to 6V...no other way than connect on on each wich really make me mad :mad:

for ppl that have them on 12V or 9V maybe it's ok, but at 6V it heats like hell

[Sparky]

So you got 12V x .53Amps = 22.64W x 3 = Say Bye Bye RheoBus.

[...]

7V x .53Amps = 13.20W x 3 per channel = 39.6W which your still majorly pushing it. You turn it to 12V and its bye bye rheobus. :rofl:

http://i58.photobucket.com/albums/g270/SparkyJJO/smileys/saywhat.gif
I knoez math! http://i58.photobucket.com/albums/g270/SparkyJJO/smileys/silly.gif

:rofl:
Just yanking your chain dude :D

[AndrewZorn]

I have three on one channel of mine. I didn't touch the heatsinks, I just know that I'm well within what the controller is rated for per channel, whatever wattage that is.

Voltage regulators get hot during normal operation anyway.

[fornowagain]

V = IR
12V = .52A X R
R = ~23ohms

I = V/R
I = 6V/23ohms
I ~ 0.2608A

For 12v, each fan draws .52A but at 6v, each fan draw ~0.2608A. I think it is right. Could someone confirm my mathematics please?

Correct, each fans resistance is 12/0.53=22.64 ohms, three fans in parallel have a third the resistance, 7.54 ohms. At 6v, 6/7.54=0.8A and 0.8x6=4.77W

[gillbot]

Ohm's law for wattage only applies to purely linear loads.

[fornowagain]

True, and the current/resistance is a simplification as its an RLE load. So ignoring back EMF, just assume static terminal resistance (RA).

[andressergio]

LOL so worried on that the channel is so hot that well today I decided how it looks with all lights on tough i'm just using channel 1 and for my surprise channel 5 it's dead :rofl: damn i'm not a lucky guy...

Can't send it back from here to get a replacement so I i saw that uses an NPN transistor D880 so i guess no other chance to replace it myself

Cheers all and thanks for the help

Sergio

[Blazing fire]

True, and the current/resistance is a simplification as its an RLE load. So ignoring back EMF, just assume static terminal resistance (RA).

Interesting. Do you mind explaining it please? I don't want to look up wiki because it isn't always accurate.

[fornowagain]

RLE means, resistance/inductance/back-emf. When a motor spins it generates a voltage in the reverse polarity to the supply, called back emf. They draw the motor schematics with a L motor winding, R resistance and a battery to represent the emf. If you stall the fan you get pure resistance for the windings etc, i.e no inductance. The power used is not linear and varies with load/speed with start up spikes etc. The voltage and current curves can be plotted, but needs a few values from the specs. If you want to work out a value for resistor to drop the voltage the simplification you used will do fine.

http://img83.imageshack.us/img83/8784/motorhv6.gif (http://imageshack.us)
http://img359.imageshack.us/img359/9674/currentnc1.gif (http://imageshack.us)

This plot explains it better than me, at stall the motor pretty much follows a resistor. With no load the motor spins way up and generates emf and the current goes down. With a load the torque increases and so does the load current, but there is still some back emf.

[Blazing fire]

What's static resistance then?

[fornowagain]

Stall/static, not moving.