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Antec 550 & Fan Only Connections

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PushPad

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Dec 26, 2002
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I would like to connect 4 case fans (Thermaltake Smart Fan IIs) to my Antec 550 PSU Fan Only power connectors, but the owners manual says not to connect more than 3 case fans to the Fan Only connectors. Would it cause any problems? Anyone done it?

Or is it better just to attach the thermo sensors to the CPU heatsink? Seems like more wire clutter though.

Can you tell I've never built a PC before. Thanks for any suggestions.
 
Given the fact that the amount of power consumed by case fans et-al varies considerably from brand to brand and rated cfm, they are probably covering their butt and basing that advice on a worse case scenario. I checked their web site, which I might mention has undergone a good overhaul and there is no power specified for the fan power so there is no absolute value to consider. Not being familiar with the ThermalTake Smart Fans, I have no idea whether they represent the low or high end in power consumption compared to other case fans. I thought I read a blurb somewhere that you should not use the True550 fan power to control fans that already have a form of variable-speed as a function of a thermal sensor. Anyone else read that?

Hoot
 
Hoot said:
I thought I read a blurb somewhere that you should not use the True550 fan power to control fans that already have a form of variable-speed as a function of a thermal sensor. Anyone else read that?

Hoot

Yes, Antec says (and it seems like common sense to me) not to use a variable speed fan on the Antec "fan-only" connectors. The reasoning is that the fan-only connectors are supplying just over 5V most of the time and it you put a variable speed controlled fan on top of that you're going to have a fan that, more likely than not, is running (or trying to run!) at some percentage less than 5V which almost for sure won't work.

If it's already a thermally variable (Which is what the TT Smart-fan II is, right?) just plug the fan into 12V and let the fan set it's own speed depending on the ambient temps.
 
The reasoning is that the fan-only connectors are supplying just over 5V most of the time and it you put a variable speed controlled fan on top of that you're going to have a fan that, more likely than not, is running (or trying to run!) at some percentage less than 5V which almost for sure won't work.

But if I don't have the thermo sensor attached, it should act just like a normal full speed case fan. Having second thoughts about attaching thermo wires all to my CPU Heatsink...because of the wire clutter. If the PSU can regulate somewhat reducing the noise and compensate when I'm playing a game, that would be cool. The TT Smart Fans are spec'd at:

Rated Voltage12VDC - Started Voltage 6VDC
20.55 CFM at 1300 rpm 2.4W and 0.20 amp 17dba (with either thermo sensor or adjustable manual controller attached)
75.7 CFM at 4800 rpm 8.4W and 0.70 amp 48dba (Full Speed-default w/no sensor)

I'm wondering if the Antec 550 can handle 4 full speed case fans instead of the owners manual suggested of 3. Emailed Antec, but still no reply.
 
We have the limit of 3 in place because when a fan stalls/is stuck it draws a lot more power then when it's running. This extra power draw is not a good thing, obviously the more fans you run the larger the chances are that you'll have one or more on the 'fan only' connectors that will fail. Once that happens it's hard to predict what will happen to your system (I'm not just talking about overheating either).


AntecRep
 
AntecRep said:
We have the limit of 3 in place because when a fan stalls/is stuck it draws a lot more power then when it's running. This extra power draw is not a good thing, obviously the more fans you run the larger the chances are that you'll have one or more on the 'fan only' connectors that will fail. Once that happens it's hard to predict what will happen to your system (I'm not just talking about overheating either).
AntecRep

I have now switched to only 3 using the Fan Only connectors (no attached sensors). The 4th fan (located on the Motherboard tray) will then use the thermo sensor ... so if I pull out the tray I won't have to retape the sensor.

Thanks all for the insight.
 
I never realised the 'fan only' molex runs at less than 12V. the yellow/black wires made me think it is 12V. does it vary according to temps then?, like the PSU fans?...
 
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