-=> The Natural Philosopher wrote to Jan Panteltje <=-

TNP> On 22/08/2023 15:16, Jan Panteltje wrote:
> On a sunny day (Tue, 22 Aug 2023 13:46:30 +0100) it happened Dr Stephen
> Strange <no.spam@me.com> wrote in
> <nvKcnT3WfrC7M3n5nZ2dnZfqn_WdnZ2d@brightview.co.uk>:
>
>> I have a Pi4 that came with a noisy 5v fan.
>>
>> If I connect the fan to the 3v line it spns slower and is much less noisy.
>>
>> Is this ok or will it damage the Pi
>
> Not a good idea, the fan will likely overload the 3 V regulator in the Pi,
TNP> also it may create noise on that 3V line
> that will affect the electronics.
> I had a noisy 5 V fan in the Pi4 4 GB, I took the fan apart, took the rotor
TNP> out and greased the shaft with some vaseline.
> That was about 2 years ago.
> It has been quiet ever since, works perfectly, 24/7.
>
TNP> you shouldn't use grease on small electric motors. Light sewing machine
TNP> oil is best.

Its an easy fix if you've done it before. Almost all fans today electric that
resemble computer type fan:
on the flat side of fan, there is a sticker.
Gently pull it off.
Under the sticker is shaft for the rotor.
Drop that tiny amount of oil in there (3 and 1) works pretty good, but use what
you have.
Put the sticker back on.
Test fan. The noise should be better.

NOTE: I use 3v pin and ground for my fan on all pies since they came out, and
since 2013 my raspi comps are still working fine. I do this because I don't
want to fix the fan as soon. Cooling with 3v works great.
___ MultiMail/Linux v0.49

On 23/08/2023 13:02, Grant Weasner wrote:
> -=> The Natural Philosopher wrote to Jan Panteltje <=-
>
> TNP> On 22/08/2023 15:16, Jan Panteltje wrote:
> > On a sunny day (Tue, 22 Aug 2023 13:46:30 +0100) it happened Dr Stephen
> > Strange <no.spam@me.com> wrote in
> > <nvKcnT3WfrC7M3n5nZ2dnZfqn_WdnZ2d@brightview.co.uk>:
> >
> >> I have a Pi4 that came with a noisy 5v fan.
> >>
> >> If I connect the fan to the 3v line it spns slower and is much less noisy.
> >>
> >> Is this ok or will it damage the Pi
> >
> > Not a good idea, the fan will likely overload the 3 V regulator in the Pi,
> TNP> also it may create noise on that 3V line
> > that will affect the electronics.
> > I had a noisy 5 V fan in the Pi4 4 GB, I took the fan apart, took the rotor
> TNP> out and greased the shaft with some vaseline.
> > That was about 2 years ago.
> > It has been quiet ever since, works perfectly, 24/7.
> >
> TNP> you shouldn't use grease on small electric motors. Light sewing machine
> TNP> oil is best.
>
> Its an easy fix if you've done it before. Almost all fans today electric that
> resemble computer type fan:
> on the flat side of fan, there is a sticker.
> Gently pull it off.
> Under the sticker is shaft for the rotor.
> Drop that tiny amount of oil in there (3 and 1) works pretty good, but use what
> you have.
> Put the sticker back on.
> Test fan. The noise should be better.
>
Yes. Cheap fans will use bronze bearings, and these will absorb light
oil. They seize up from the oil drying out. A good soaking in a light
oil will sort them out. Grease will work, but it will dry out fast than oil.
Better classes of fan would use sealed ball bearings, which you cant oil
anyway.

>
> NOTE: I use 3v pin and ground for my fan on all pies since they came out, and
> since 2013 my raspi comps are still working fine. I do this because I don't
> want to fix the fan as soon. Cooling with 3v works great.
>
My time on high powered electronics staring at the cooling curves of fan
blown heatsinks shows that a huge draught is not required. Convection is
a very slow air movement. As soon as *any* wind is persent, the heatloss
improves massively. It is less a case of 'forced cooling' than 'removing
the hot air just above the surface'.

--
Future generations will wonder in bemused amazement that the early
twenty-first century’s developed world went into hysterical panic over a
globally average temperature increase of a few tenths of a degree, and,
on the basis of gross exaggerations of highly uncertain computer
projections combined into implausible chains of inference, proceeded to
contemplate a rollback of the industrial age.

Richard Lindzen