Sunbeam Rheobus works with 24W Delta (190cfm)?

Falkentyne · Sep 26, 2006

Ok, I thought this combo was not supposed to work.
First, the sunbeam is only 20W/channel, while the Delta is a 24W fan.
Second, the Delta (it's a 120x38mm FFB1212EHE) requires *3 amps* to startup, according to Sidewinder computers (great seller btw) and uses 2 amps (12v * 2A = 24W).

Yet I hooked this fan up (briefly) to my Sunbeam and it started right up?!
And the fan control dial worked too...

(needless to say the Delta almost 'took off' from my hand like a self-enclosed jet engine...)

I only tested this briefly, but why did this work? Electron Chaser?
Every post I've found in a search says that the Sunbeam did not power up other people's Deltas....yet mine powered up....

How was it able to start up when Sunbeam Rheobuses only (allegedly) put out 1.67 amps? (and 1.67a*12v=20W)

(now maybe I might wind up blowing out the connector on the sunbeam but I'll definitely try to mount it later to tame the Delta that's trying to tame my X6800...and see what happens :/)

BTW the fan was not spinning at full speed (just like my Tornado also doesn't quite spin at full speed....), I estimate the fan was running at maybe 15-20% under normal RPM (max RPM=4000), but it wasn't hooked up to a computer for this test.

Adragontattoo · Sep 26, 2006

Yes it will "work" but you WILL overheat that Rheo and potentially cause a fire. Your call on if you really want to do that, personally I dont enjoy the smell or sight of my rig in flames.

Falkentyne · Sep 26, 2006

Thanks for the important heads up on this.
:beer:

Since this is overclockers.com, I decided to run an out of case overclocking test and overclock the Rheobus ~_~

I only attempted this since the Sunbeam comes with heatsinks, which makes this less crazy than it sounds

and makes sane testing very simple.

At full dial setting, the Delta worked perfectly. the heatsink got a little warm, but it was nothing to really be worried about. Heatsink temp felt between 40-50C, the average of most computer aircooled heatsinks. I suspect this could be run like this 24/7.

*BUT*...
As Electron chaser mentioned in an older thread....
turning down the voltage dial is a whole different story.

At 7 volts, the Delta slowed down predictably, but the heatsink started to get warm. And warmer....and warmer....and then......(thermonuclear explosion).
....

Project canceled before there was any chance of a fire

Ok nothing broke, but when the heatsink got almost too warm to hold my finger on comfortably (I suspect this was at least 65C, maybe 70, as I did a similar test with an XP-90 passively cooling a P4EE@load to find the throttling temp), I decided enough's enough and turned off the Rheo and put the Delta back into the main computer. Safe sane test, but caveat emptor~

Do not attempt this with the 220cfm fan

The amp draw goes up as the voltage goes down, is this correct? So it looks like the Sunbeam can be overclocked minimally (it can handle 2 amps due to the heatsinks) and run the 190cfm Delta at full load, but can NOT handle turning down that fan, which is the whole point of even wanting to use a fan controller -.-.

I'll have to get that 50W Rheo from sidewinder computers....

If only I could mount my spare XP-90 to that tiny chip on the Sunbeam....THEN I could have some Delta fun...

(someone needs a fire emoticon)

Adragontattoo · Sep 26, 2006

DO NOT BUY THOSE KNOBS!!! 5.50 a piece WTF sidewinder!

I can get them at radio shack for under 3 bucks for 2!

Sorry for the caps but that price is ridiculous..

nd4spdbh2 · Sep 26, 2006

Falkentyne said:
Thanks for the important heads up on this.

Since this is overclockers.com, I decided to run an out of case overclocking test and overclock the Rheobus ~_~

I only attempted this since the Sunbeam comes with heatsinks, which makes this less crazy than it sounds and makes sane testing very simple.

At full dial setting, the Delta worked perfectly. the heatsink got a little warm, but it was nothing to really be worried about. Heatsink temp felt between 40-50C, the average of most computer aircooled heatsinks. I suspect this could be run like this 24/7.

*BUT*...
As Electron chaser mentioned in an older thread....
turning down the voltage dial is a whole different story.

At 7 volts, the Delta slowed down predictably, but the heatsink started to get warm. And warmer....and warmer....and then......(thermonuclear explosion).
....

Project canceled before there was any chance of a fire

Ok nothing broke, but when the heatsink got almost too warm to hold my finger on comfortably (I suspect this was at least 65C, maybe 70, as I did a similar test with an XP-90 passively cooling a P4EE@load to find the throttling temp), I decided enough's enough and turned off the Rheo and put the Delta back into the main computer. Safe sane test, but caveat emptor~

Do not attempt this with the 220cfm fan

The amp draw goes up as the voltage goes down, is this correct? So it looks like the Sunbeam can be overclocked minimally (it can handle 2 amps due to the heatsinks) and run the 190cfm Delta at full load, but can NOT handle turning down that fan, which is the whole point of even wanting to use a fan controller -.-.

I'll have to get that 50W Rheo from sidewinder computers....

If only I could mount my spare XP-90 to that tiny chip on the Sunbeam....THEN I could have some Delta fun... (someone needs a fire emoticon)

the reason the controler works when its turned up all the way is because its not having to turn the voltage from 12 down to the desired voltage.... all it takes is some simple math...

with knob turn all the way to max voltage u probably get about 11.75-11.5... lets say 11.5

so the voltage lost between the input of 12v and the output of 11.5 volts is .5 volts.... NOW to get rid of that .5 volts it is turned into heat... so .5 x 2amps = 1w... thus you had to disipate 1 watt of heat...

NOW when you turn the knob down so ur multimeter reads 7 volts this is a todally different story because now your having to disipate 12-7 = 5 and 5v x 2amps = 10watts of heat... which is ALOT for a small passive heatsink to disipate.

ALSO this is assuming that the transistors / voltage regulators on the circuit can handel the 2amp load to begin with WHICH they probably cant for extended periods.... and as you turn down the voltage the fan does not draw more energy.... it draws the same amps but less watts.

Falkentyne · Sep 26, 2006

Adragontattoo said:
DO NOT BUY THOSE KNOBS!!! 5.50 a piece WTF sidewinder!

I can get them at radio shack for under 3 bucks for 2!

Sorry for the caps but that price is ridiculous..

You mean the knobs or the 50W 'stat itself?

Falkentyne · Sep 26, 2006

Good post, nd4.

I could probably mount a fan on the heatsink quite easily, but then I would need two drive bays to mount the thing...which I really don't have. (well I do but I would have to shuffle my two DVDs and Creative xfi console around-.-)

No idea if the regulators can handle the draw or not. I didn't see any hot spots except the IC the heatsink was connected to....

Would be a great ghetto mod though....

Adragontattoo · Sep 26, 2006

The knobs.

Falkentyne said:
You mean the knobs or the 50W 'stat itself?

Cyrix_2k · Sep 26, 2006

I burnt a channel on my sunbeam after I ran my MCP600 on it for a while

So, for those of you wondering if you can kill the sunbeam, you can.

Sleepy_Steve · Sep 27, 2006

Might be a bit of a dumb question but cant you set it up so the massive fan uses two chanels from the fan controler?
I belive this would be setting it up in parallel (right term?)... not 100% if it would work though. But i think A little bit of home made wireing is all you need to give it a try.

Sunbeam Rheobus works with 24W Delta (190cfm)?

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