Just on the off-chance someone may have done this before.

My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL
modem & Ethernet switch.

Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.

Seen one such cct:

http://www.bit-tech.net/modding/2001...n_controller/1

(option 3 )


Anybody got anything easier.




--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On Mon, 09 Jun 2014 22:54:46 +0100, Rick Hughes wrote:

Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)

The 3rd wire is just a tacho output. 4 wire introduces a dedicated
PWM speed control wire. 2 and 3 wire fans are happy, within limits,
with direct PWM, provided you aren't interested in a sensible tacho
signal from a 3 wire.

and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.

Seen one such cct:

http://www.bit-tech.net/modding/2001...n_controller/1

(option 3 )

Anybody got anything easier.

There is a chip, MIC502, that does all the grunt work for PWM
control. Just add a few minor components, can't be any easier. B-)

--
Cheers
Dave.

In article ,
Rick Hughes writes:
Just on the off-chance someone may have done this before.

My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL
modem & Ethernet switch.

Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.

Anybody got anything easier.

I simply use a on/off thermostat (needs to be changeover or designed for
cooling, so you can switch *on* when it gets hot).

Well, I say *simply* - mine is actually done by software rather than
a crude bi-metallic stat, but the latter should work just fine.

I used to run a minicomputer at home, and did the same for that, although
I used a Maplin min-max temperature module (FP64U, no longer sold, but
still references on the web). You could set a min and max threshold, and
when it went over the min, it switched the fan on, and when it went over
the max, it cut the computer power (which remained latched off by an
external circuit until manually reset). FP64U was an extremely useful
and cheap building block module, and it's a shame nothing similar seems
to exist anymore.

Proportional fan speed control wasn't really required - nothing in either
the minicomputer or my PC today is that temperature sensitive.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article , Rick Hughes
writes
Just on the off-chance someone may have done this before.

My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL
modem & Ethernet switch.

Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.

Seen one such cct:

http://www.bit-tech.net/modding/2001...n_controller/1

(option 3 )


Anybody got anything easier.

If you don't mind something ticking over slowly all the time then they
do already make self contained PC fans with temperature based speed
control.

Here's an example (not used, just found on a search):

http://www.quietpc.com/ac-arctic-f12-pro-tc

http://www.amazon.co.uk/dp/B002G3CKX4

That one has a temp sensor on a 40cm lead but an example I have used
(Coolermaster I think) just had a thermistor directly in the fan airflow
so that when used as an exhaust fan it would monitor the exhaust temp.
--
fred
it's a ba-na-na . . . .

On Monday, June 9, 2014 10:54:46 PM UTC+1, Rick Hughes wrote:
Just on the off-chance someone may have done this before.
My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL
modem & Ethernet switch.
Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.
Seen one such cct:
http://www.bit-tech.net/modding/2001...n_controller/1
(option 3 )
Anybody got anything easier.

opamp measures Vbe, compares it to R divider on regulated line. Small power tr output, voila, Vout depends on temp. A small cap cuses it to come on full V at power up. A 2nd*opa zeroes base drive when Vout is too low.

With a 3rd opa you could pwm it.


NT

Andrew Gabriel wrote:

I simply use a on/off thermostat (needs to be changeover or designed for
cooling, so you can switch *on* when it gets hot).

Well, I say *simply* - mine is actually done by software rather than
a crude bi-metallic stat, but the latter should work just fine.

It does because that's how I did it for the charger cabinet in my
motorhome. The two chargers abd the 24/12 converter have their own stats
and fans but it was also necessary to ventilate the cabinet. A large
diameter flexi tube allows air to enter from under the vehicle, and a
fan pushes air out of the cabinet. The stat is set to 30C. Any lower and
the fan runs due to the ambient temp, even when the chargers aren't active.

Bill

On 09/06/2014 23:58, Andrew Gabriel wrote:

Proportional fan speed control wasn't really required - nothing in either
the minicomputer or my PC today is that temperature sensitive.



I just looked at what my PC does ,,, it has variable speed cooling fan
on processor heatsink stack and also 3 x 4" fans again all variable speed.
Does mean computer is very quiet unless doing significant video coding
and then fans speed up accordingly (as to GPU fans)

Sort of assumed as this is now common place there may be simple way to
build a free-standing version.

--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On 10/06/2014 01:25, fred wrote:


If you don't mind something ticking over slowly all the time then they
do already make self contained PC fans with temperature based speed
control.

Here's an example (not used, just found on a search):

http://www.quietpc.com/ac-arctic-f12-pro-tc

http://www.amazon.co.uk/dp/B002G3CKX4

That one has a temp sensor on a 40cm lead but an example I have used
(Coolermaster I think) just had a thermistor directly in the fan airflow
so that when used as an exhaust fan it would monitor the exhaust temp.


want to get one that is 'off' below a set temp (30 deg probably) as
hopefully means most of time I'm not paying to run fan.


I have coolermaster psu on my PC's good kit.


--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On Tue, 10 Jun 2014 13:40:57 +0100, Rick Hughes wrote:

That one has a temp sensor on a 40cm lead but an example I have
used
(Coolermaster I think) just had a thermistor directly in the fan
airflow so that when used as an exhaust fan it would monitor the
exhaust temp.

want to get one that is 'off' below a set temp (30 deg probably) as
hopefully means most of time I'm not paying to run fan.

A fan doesn't take a lot but "from little acorns do oak trees grow".

Just wire a stat in series with a fan with built in temperature speed
control if you don't want to build the MIC502 circuit.

--
Cheers
Dave.

In article , Rick Hughes
writes
On 10/06/2014 01:25, fred wrote:


If you don't mind something ticking over slowly all the time then they
do already make self contained PC fans with temperature based speed
control.

Here's an example (not used, just found on a search):

http://www.quietpc.com/ac-arctic-f12-pro-tc

http://www.amazon.co.uk/dp/B002G3CKX4

That one has a temp sensor on a 40cm lead but an example I have used
(Coolermaster I think) just had a thermistor directly in the fan airflow
so that when used as an exhaust fan it would monitor the exhaust temp.

want to get one that is 'off' below a set temp (30 deg probably) as
hopefully means most of time I'm not paying to run fan.

I can understand that but the one I linked to is just 2.16W at full
whack (1300rpm). At min speed (400rpm) I doubt it will be more than a
watt, possibly as low as a half so 50p to £1pa and I don't get out of
bed for those kind of savings.
--
fred
it's a ba-na-na . . . .

In article ,
Rick Hughes writes:
On 09/06/2014 23:58, Andrew Gabriel wrote:

Proportional fan speed control wasn't really required - nothing in either
the minicomputer or my PC today is that temperature sensitive.

I just looked at what my PC does ,,, it has variable speed cooling fan
on processor heatsink stack and also 3 x 4" fans again all variable speed.
Does mean computer is very quiet unless doing significant video coding
and then fans speed up accordingly (as to GPU fans)

Sort of assumed as this is now common place there may be simple way to
build a free-standing version.

Processor fan is done in software. It's done by the BIOS in SMM
(System Management Mode), although some BIOSes will allow the
operating system to take over control if the OS knows how to.

Variable power supply fans are sometimes done by measuring
temperature of a heatsink in the PSU or exhaust temperature,
and in smarter PSU's which provide power consumption data for
the powerating system, it can be based on the consumption of
the system as a whole (depends if the PSU fans are also cooling
the whole system, or just the PSU).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 10/06/2014 15:30, Andrew Gabriel wrote:


Variable power supply fans are sometimes done by measuring
temperature of a heatsink in the PSU or exhaust temperature,
and in smarter PSU's which provide power consumption data for
the powerating system, it can be based on the consumption of
the system as a whole (depends if the PSU fans are also cooling
the whole system, or just the PSU).



My case fans are also variable speed - and that is what I think would
suit the task ... 4" fan speed variable by temp.

--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On 09/06/2014 23:39, Dave Liquorice wrote:


There is a chip, MIC502, that does all the grunt work for PWM
control. Just add a few minor components, can't be any easier. B-)



BTW ... the cct I gave link to does use the MIC502 chip

--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On Tue, 10 Jun 2014 18:20:47 +0100, Rick Hughes wrote:

There is a chip, MIC502, that does all the grunt work for PWM
control. Just add a few minor components, can't be any easier.
B-)

BTW ... the cct I gave link to does use the MIC502 chip

Missed smilely?

Apart from the stat and fan with built in temperature speed control
you can't get much simpler than using the MIC502.

--
Cheers
Dave.

On Tuesday, June 10, 2014 2:17:05 AM UTC+1, wrote:
On Monday, June 9, 2014 10:54:46 PM UTC+1, Rick Hughes wrote:

Just on the off-chance someone may have done this before.
My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL
modem & Ethernet switch.
Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.
Seen one such cct:
http://www.bit-tech.net/modding/2001...n_controller/1
(option 3 )
Anybody got anything easier.

opamp measures Vbe, compares it to R divider on regulated line. Small power tr output, voila, Vout depends on temp. A small cap cuses it to come on full V at power up. A 2nd opa zeroes base drive when Vout is too low.
With a 3rd opa you could pwm it.
NT

Easier: 2 bimetal stats, 1 feeding half power


NT

On 10/06/2014 20:52, Dave Liquorice wrote:
On Tue, 10 Jun 2014 18:20:47 +0100, Rick Hughes wrote:

There is a chip, MIC502, that does all the grunt work for PWM
control. Just add a few minor components, can't be any easier.
B-)

BTW ... the cct I gave link to does use the MIC502 chip

Missed smilely?

Apart from the stat and fan with built in temperature speed control
you can't get much simpler than using the MIC502.



sorry missed that ....
They are only £2.50 as well so might as well try one out.



--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On Tue, 10 Jun 2014 14:49:42 +0100, fred wrote:

In article , Rick Hughes
writes
On 10/06/2014 01:25, fred wrote:


If you don't mind something ticking over slowly all the time then they
do already make self contained PC fans with temperature based speed
control.

Here's an example (not used, just found on a search):

http://www.quietpc.com/ac-arctic-f12-pro-tc

http://www.amazon.co.uk/dp/B002G3CKX4

That one has a temp sensor on a 40cm lead but an example I have used
(Coolermaster I think) just had a thermistor directly in the fan airflow
so that when used as an exhaust fan it would monitor the exhaust temp.

want to get one that is 'off' below a set temp (30 deg probably) as
hopefully means most of time I'm not paying to run fan.

I can understand that but the one I linked to is just 2.16W at full
whack (1300rpm). At min speed (400rpm) I doubt it will be more than a
watt, possibly as low as a half so 50p to £1pa and I don't get out of
bed for those kind of savings.

He was probably referring more to the price of enduring the
discomfort of a noisy fan rather than its modest annual energy cost.

There's more than one way to 'pay a price' beyond that measured
purely in monetary terms. It's the main reason why I'm not tempted to
employ spin down power saving on my 4 disk NAS box.

I regard the potential 30 quid a year saving I'm eschewing as an
'insurance premium' to minimise the risk of catastrophic disk failure
(and data loss). It's a strategy that seems to have worked ok for the
past 2 1/2 decades thus far (fingers crossed).
--
J B Good

In article , Johny B Good
writes
On Tue, 10 Jun 2014 14:49:42 +0100, fred wrote:

I can understand that but the one I linked to is just 2.16W at full
whack (1300rpm). At min speed (400rpm) I doubt it will be more than a
watt, possibly as low as a half so 50p to £1pa and I don't get out of
bed for those kind of savings.

He was probably referring more to the price of enduring the
discomfort of a noisy fan rather than its modest annual energy cost.

"The ARCTIC F Pro TC is therefore completely inaudible (0.05 sone) at
low temperatures a much quieter level than generic TC fans."

--
fred
it's a ba-na-na . . . .

On Wed, 11 Jun 2014 15:09:02 +0100, Johny B Good wrote:

He was probably referring more to the price of enduring the discomfort
of a noisy fan rather than its modest annual energy cost.

There is that but the cure is easy: Bigger slower fan. Shifts the
same amount of air but gently so far far less noise. The HP
microserver has a large slow fan, 120 mm, almost inaudible, unlike
the 80 mm PSU fan in the PC.

--
Cheers
Dave.

On 11/06/2014 22:37, Dave Liquorice wrote:
On Wed, 11 Jun 2014 15:09:02 +0100, Johny B Good wrote:

He was probably referring more to the price of enduring the discomfort
of a noisy fan rather than its modest annual energy cost.

There is that but the cure is easy: Bigger slower fan. Shifts the
same amount of air but gently so far far less noise. The HP
microserver has a large slow fan, 120 mm, almost inaudible, unlike
the 80 mm PSU fan in the PC.


anybody know of a good make quiet & reasonably cheap 120mm fan ...


--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On 12/06/14 15:00, Rick Hughes wrote:
On 11/06/2014 22:37, Dave Liquorice wrote:
On Wed, 11 Jun 2014 15:09:02 +0100, Johny B Good wrote:

He was probably referring more to the price of enduring the discomfort
of a noisy fan rather than its modest annual energy cost.

There is that but the cure is easy: Bigger slower fan. Shifts the
same amount of air but gently so far far less noise. The HP
microserver has a large slow fan, 120 mm, almost inaudible, unlike
the 80 mm PSU fan in the PC.


anybody know of a good make quiet & reasonably cheap 120mm fan ...



Good, cheap, quiet - choose any two...


http://www.quietpc.com/120mmfans

Noctura - not cheap, but I have 2 of their 40mm fans and I cannot even
hear them (with the speed dropper in - I only need a waft for a
"fanless" ITX board that runs a tad warm with no fan).

On 12/06/2014 15:00, Rick Hughes wrote:
On 11/06/2014 22:37, Dave Liquorice wrote:
On Wed, 11 Jun 2014 15:09:02 +0100, Johny B Good wrote:

He was probably referring more to the price of enduring the discomfort
of a noisy fan rather than its modest annual energy cost.

There is that but the cure is easy: Bigger slower fan. Shifts the
same amount of air but gently so far far less noise. The HP
microserver has a large slow fan, 120 mm, almost inaudible, unlike
the 80 mm PSU fan in the PC.


anybody know of a good make quiet & reasonably cheap 120mm fan ...




Just bought ARTIC Cooling FT PRO TC 120mm for pricely sum of £3.19
incl 1st class post :-)

As I have ARTIC coling fans in PC and on processor ... they7 seem good
.... so bought one of them.


Going with the MIC502 based cct ........ have sourced all the parts.



--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/

On Thu, 12 Jun 2014 15:20:53 +0100, Tim Watts
wrote:

On 12/06/14 15:00, Rick Hughes wrote:
On 11/06/2014 22:37, Dave Liquorice wrote:
On Wed, 11 Jun 2014 15:09:02 +0100, Johny B Good wrote:

He was probably referring more to the price of enduring the discomfort
of a noisy fan rather than its modest annual energy cost.

There is that but the cure is easy: Bigger slower fan. Shifts the
same amount of air but gently so far far less noise. The HP
microserver has a large slow fan, 120 mm, almost inaudible, unlike
the 80 mm PSU fan in the PC.


anybody know of a good make quiet & reasonably cheap 120mm fan ...



Good, cheap, quiet - choose any two...

Puts me in mind of a slogan used by a repair shop:-

"We can do high quality, fast and cheap repairs but you're only
allowed the choice of any two options."



http://www.quietpc.com/120mmfans

Noctura - not cheap, but I have 2 of their 40mm fans and I cannot even
hear them (with the speed dropper in - I only need a waft for a
"fanless" ITX board that runs a tad warm with no fan).

--
J B Good

On Tuesday, June 10, 2014 11:48:01 PM UTC+1, wrote:
On Tuesday, June 10, 2014 2:17:05 AM UTC+1, wrote:
On Monday, June 9, 2014 10:54:46 PM UTC+1, Rick Hughes wrote:


Maybe if I use a 3 lead variable speed DC brushless fan (as in PC cases)
and a tenp sensor I could get a simple fan that kicks in above a set
temp and varies it's speed dependent of how hot it is above threshold.
Seen one such cct:
http://www.bit-tech.net/modding/2001...n_controller/1
(option 3 )
Anybody got anything easier.

opamp measures Vbe, compares it to R divider on regulated line. Small power tr output, voila, Vout depends on temp. A small cap cuses it to come on full V at power up. A 2nd opa zeroes base drive when Vout is too low.

With a 3rd opa you could pwm it.

Easier: 2 bimetal stats, 1 feeding half power

Or just 1 thermistor & 1 tr, if you can calculate correctly.


NT

On 11/06/2014 16:11, fred wrote:
In article , Johny B Good
writes
On Tue, 10 Jun 2014 14:49:42 +0100, fred wrote:

I can understand that but the one I linked to is just 2.16W at full
whack (1300rpm). At min speed (400rpm) I doubt it will be more than a
watt, possibly as low as a half so 50p to £1pa and I don't get out of
bed for those kind of savings.

He was probably referring more to the price of enduring the
discomfort of a noisy fan rather than its modest annual energy cost.

"The ARCTIC F Pro TC is therefore completely inaudible (0.05 sone) at
low temperatures a much quieter level than generic TC fans."



Fred ... do you know how to 'disable' the temp sensor on these fans ?



--
UK SelfBuild: http://uk.groups.yahoo.com/group/UK_Selfbuild/