External cooling fans - source
From time to time, the subject of external cooling fans comes up -- for
example, in discussions of the HP 5370A/B with their steaming hot
heatsinks. I have several times recommended very quiet, all-metal, 4"
desk fans as ideal for the job, but have not been able to suggest a source.
Wandering through my neighborhood TrueValue hardware store recently, I
found the exact fan I bought previously. Just to be sure, I bought a
couple more. And yes, indeed, these are the exact items I have
recommended so highly in the past. See photo attached below.
The fans are available from the TrueValue online store -- and at a
whopping discount from the in-store price ($8.99 online vs. $13.99
locally). If you have a local TrueValue store that either doesn't stock
the fans or charges more than $9 for them, you can order online and have
them delivered to your local store for free.
Here's a link:
http://www.truevalue.com/product/Heating-Cooling/Fans/Personal-Table-Fans/High-Velocity-Tilt-Fan-4-In-/pc/7/c/102/sc/1126/23003.uts
This is the black model. For design-conscious time nuts, they are
also available in red and blue.
I have a stack of three 5370Bs at one workstation, and one of these fans
blowing directly at the heatsinks from close-up (about 6") and a little
below the bottom counter keeps all three heatsinks just warm to the
touch. Without the external fan, you don't want to leave your hand on
the heatsink for more than a few seconds.
When I say they are quiet, I mean nearly dead silent. Even if the
internal fans made no noise at all, you would still never hear the
external fan from in front of the counters. (As anyone who has a 5370
can attest, the internal fans are very, very far from silent.)
The fan motors are open-frame, so when the bearings eventually go dry it
should be easy enough to re-lubricate them with synthetic oil such as
Mobil 1. (I've had several of these fans running 24/7 for more than 5
years, and there is no sign of bearing issues so far.)
At $9 each, most of us can probably afford to buy enough to meet our
immediate needs as well as some spares to use with hot equipment we have
yet to acquire....
Finally, with a little ingenuity and some ducting, these fans can be
kludged ... er, pardon me ... retrofitted ... to other equipment. I
plan to replace the internal fans in a number of obnoxiously loud
instruments (HP, SRS SR620, desktop computers, etc.), or to add fan
cooling to equipment that needs it (Collins HF2050, R390, etc.).
Best regards,
Charles
On 18 December 2017 at 23:11, Charles Steinmetz csteinmetz@yandex.com
wrote:
From time to time, the subject of external cooling fans comes up -- for
example, in discussions of the HP 5370A/B with their steaming hot
heatsinks. I have several times recommended very quiet, all-metal, 4" desk
fans as ideal for the job, but have not been able to suggest a source.
For what it is worth, my 5370B run very hot, which forced me to check my
mains voltage as I knew every time I had done a quick measurement, the
voltage was above 230 V. So for a few days I logged the voltage, and found
it was consistently high. The maximum permitted here in the UK is 253 V,
but I measured mine at 255.x volts. It was the heat of the 5370B that
forced me to contact the electricity supply company (UK Power Networks),
who logged the voltage for 4 days. I have a 3-phase supply here, which is
unusual for a domestic property, but each of the 3 phases was consistently
high. I managed to get the supply company to reduce the voltage by 5%. That
made a significant difference in the heatsink temperature of the 5370B,
and a significant difference to to the exhaust temperature of my HP 70000
series system.
I'm not saying an extra fan is not a good idea, but it is certainly worth
ensuring the mains voltage is not too high. I was told by UK Power Networks
that they aim for 245-250 V in rural areas - this is despite the UK is
supposed to be 230 -6%/+10%. On equipment with linear power supplies, a few
extra volts can lead to a significant increase in the amount of heat the
regulators produce. 10% extra voltage does not equate to 10% extra power
dissipation, but considerably more.
I found quite a reluctance on the part of the UK Power Networks to reduce
the voltage. Even though it was was on average more than 5% high, the
technical manager who took ownership of the problem only wanted to reduce
the voltage by 2.5%, despite they could easily reduce it 5%. Luckily, when
the engineers came to adjust the supply voltage, (which they do by changing
the taps on the 11 kV primary), I managed to convince them that there were
very few properties on the transformer, and the furthest was an old couple
that used very little electricity. So they did reduce it 5%, which is the
maximum they could. But they warned me that if there were complaints of low
voltage, they would have to increase it 2.5%. Luckily for me, nobody
locally noticed the reduction in mains voltage, and it is still on average
over 230 V.
It would be interesting to know how low the AC input can go on a 5370B
before the regulators fail to regulate. Given they are the sort of
instrument one might want to run for long periods, running one on a UPS,
with a transformer to reduce the output of the UPS, might not be such a bad
idea.
Charles
Dave
Hi
Yes, this is a bit off topic. Sorry about that … I’m sure it’ll never / ever happen
again :) …. ummm …. today ….
The voltage that supply feeds are set to is as much a public relations issue as a
technical one. People would routinely complain “the lights are to dim”. Voltage
gets bumped up. Complaints drop off. Eventually you are right at (or as you observe
marginally above) the max limits. Since the power company is paid by the watt, the
added power usage (if any) is not a big deal. The call outs for checks are a big
deal to them ….. complaints impact the metrics by which they are judged ….
Bob
On Dec 19, 2017, at 12:48 AM, Dr. David Kirkby drkirkby@kirkbymicrowave.co.uk wrote:
On 18 December 2017 at 23:11, Charles Steinmetz csteinmetz@yandex.com
wrote:
From time to time, the subject of external cooling fans comes up -- for
example, in discussions of the HP 5370A/B with their steaming hot
heatsinks. I have several times recommended very quiet, all-metal, 4" desk
fans as ideal for the job, but have not been able to suggest a source.
For what it is worth, my 5370B run very hot, which forced me to check my
mains voltage as I knew every time I had done a quick measurement, the
voltage was above 230 V. So for a few days I logged the voltage, and found
it was consistently high. The maximum permitted here in the UK is 253 V,
but I measured mine at 255.x volts. It was the heat of the 5370B that
forced me to contact the electricity supply company (UK Power Networks),
who logged the voltage for 4 days. I have a 3-phase supply here, which is
unusual for a domestic property, but each of the 3 phases was consistently
high. I managed to get the supply company to reduce the voltage by 5%. That
made a significant difference in the heatsink temperature of the 5370B,
and a significant difference to to the exhaust temperature of my HP 70000
series system.
I'm not saying an extra fan is not a good idea, but it is certainly worth
ensuring the mains voltage is not too high. I was told by UK Power Networks
that they aim for 245-250 V in rural areas - this is despite the UK is
supposed to be 230 -6%/+10%. On equipment with linear power supplies, a few
extra volts can lead to a significant increase in the amount of heat the
regulators produce. 10% extra voltage does not equate to 10% extra power
dissipation, but considerably more.
I found quite a reluctance on the part of the UK Power Networks to reduce
the voltage. Even though it was was on average more than 5% high, the
technical manager who took ownership of the problem only wanted to reduce
the voltage by 2.5%, despite they could easily reduce it 5%. Luckily, when
the engineers came to adjust the supply voltage, (which they do by changing
the taps on the 11 kV primary), I managed to convince them that there were
very few properties on the transformer, and the furthest was an old couple
that used very little electricity. So they did reduce it 5%, which is the
maximum they could. But they warned me that if there were complaints of low
voltage, they would have to increase it 2.5%. Luckily for me, nobody
locally noticed the reduction in mains voltage, and it is still on average
over 230 V.
It would be interesting to know how low the AC input can go on a 5370B
before the regulators fail to regulate. Given they are the sort of
instrument one might want to run for long periods, running one on a UPS,
with a transformer to reduce the output of the UPS, might not be such a bad
idea.
Charles
Dave
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
I put a small external fan on my 5370B, which keeps the heat sink at a
reasonable low temperature (Time-Nut content) -but- (Nixon segué) the power
company here also runs the voltage all the way up to the limit (126VAC)
because "many of our [rural, like me] customers are all-electric and the
load tends to pull the voltage down during times of peak use." The voltage
got so high I finally put a recorder on it and walked the results into
their office. In response, they attached their recorder to my connection
and ran it for a couple of weeks before agreeing with me. Then they
reluctantly turned the transformer down a notch so we stay below 126VAC now.
Jeremy
On Tue, Dec 19, 2017 at 5:44 AM Bob kb8tq kb8tq@n1k.org wrote:
Hi
Yes, this is a bit off topic. Sorry about that … I’m sure it’ll never /
ever happen
again :) …. ummm …. today ….
The voltage that supply feeds are set to is as much a public relations
issue as a
technical one. People would routinely complain “the lights are to dim”.
Voltage
gets bumped up. Complaints drop off. Eventually you are right at (or as
you observe
marginally above) the max limits. Since the power company is paid by the
watt, the
added power usage (if any) is not a big deal. The call outs for checks
are a big
deal to them ….. complaints impact the metrics by which they are judged ….
Bob
On Dec 19, 2017, at 12:48 AM, Dr. David Kirkby <
drkirkby@kirkbymicrowave.co.uk> wrote:
On 18 December 2017 at 23:11, Charles Steinmetz csteinmetz@yandex.com
wrote:
From time to time, the subject of external cooling fans comes up -- for
example, in discussions of the HP 5370A/B with their steaming hot
heatsinks. I have several times recommended very quiet, all-metal, 4"
desk
fans as ideal for the job, but have not been able to suggest a source.
For what it is worth, my 5370B run very hot, which forced me to check my
mains voltage as I knew every time I had done a quick measurement, the
voltage was above 230 V. So for a few days I logged the voltage, and
found
it was consistently high. The maximum permitted here in the UK is 253 V,
but I measured mine at 255.x volts. It was the heat of the 5370B that
forced me to contact the electricity supply company (UK Power Networks),
who logged the voltage for 4 days. I have a 3-phase supply here, which is
unusual for a domestic property, but each of the 3 phases was
consistently
high. I managed to get the supply company to reduce the voltage by 5%.
That
made a significant difference in the heatsink temperature of the 5370B,
and a significant difference to to the exhaust temperature of my HP 70000
series system.
I'm not saying an extra fan is not a good idea, but it is certainly worth
ensuring the mains voltage is not too high. I was told by UK Power
Networks
that they aim for 245-250 V in rural areas - this is despite the UK is
supposed to be 230 -6%/+10%. On equipment with linear power supplies, a
few
extra volts can lead to a significant increase in the amount of heat the
regulators produce. 10% extra voltage does not equate to 10% extra
power
dissipation, but considerably more.
I found quite a reluctance on the part of the UK Power Networks to reduce
the voltage. Even though it was was on average more than 5% high, the
technical manager who took ownership of the problem only wanted to reduce
the voltage by 2.5%, despite they could easily reduce it 5%. Luckily,
when
the engineers came to adjust the supply voltage, (which they do by
changing
the taps on the 11 kV primary), I managed to convince them that there
were
very few properties on the transformer, and the furthest was an old
couple
that used very little electricity. So they did reduce it 5%, which is the
maximum they could. But they warned me that if there were complaints of
low
voltage, they would have to increase it 2.5%. Luckily for me, nobody
locally noticed the reduction in mains voltage, and it is still on
average
over 230 V.
It would be interesting to know how low the AC input can go on a 5370B
before the regulators fail to regulate. Given they are the sort of
instrument one might want to run for long periods, running one on a UPS,
with a transformer to reduce the output of the UPS, might not be such a
bad
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Sent from my iPad 4.
In the US, I have seen line voltage as low as 70VAC and as high as 145VAC.
That's what I design to.
The power companies say different, but my meters don't lie.
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Jeremy Nichols
Sent: Tuesday, December 19, 2017 9:20 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] External cooling fans - source
I put a small external fan on my 5370B, which keeps the heat sink at a reasonable low temperature (Time-Nut content) -but- (Nixon segué) the power company here also runs the voltage all the way up to the limit (126VAC) because "many of our [rural, like me] customers are all-electric and the load tends to pull the voltage down during times of peak use." The voltage got so high I finally put a recorder on it and walked the results into their office. In response, they attached their recorder to my connection and ran it for a couple of weeks before agreeing with me. Then they reluctantly turned the transformer down a notch so we stay below 126VAC now.
Jeremy
On Tue, Dec 19, 2017 at 5:44 AM Bob kb8tq kb8tq@n1k.org wrote:
Hi
Yes, this is a bit off topic. Sorry about that … I’m sure it’ll
never / ever happen again :) …. ummm …. today ….
The voltage that supply feeds are set to is as much a public relations
issue as a technical one. People would routinely complain “the lights
are to dim”.
Voltage
gets bumped up. Complaints drop off. Eventually you are right at (or
as you observe marginally above) the max limits. Since the power
company is paid by the watt, the added power usage (if any) is not a
big deal. The call outs for checks
are a big
deal to them ….. complaints impact the metrics by which they are judged ….
Bob
On Dec 19, 2017, at 12:48 AM, Dr. David Kirkby <
drkirkby@kirkbymicrowave.co.uk> wrote:
On 18 December 2017 at 23:11, Charles Steinmetz
csteinmetz@yandex.com
wrote:
From time to time, the subject of external cooling fans comes up --
for example, in discussions of the HP 5370A/B with their steaming
hot heatsinks. I have several times recommended very quiet, all-metal, 4"
desk
fans as ideal for the job, but have not been able to suggest a source.
For what it is worth, my 5370B run very hot, which forced me to
check my mains voltage as I knew every time I had done a quick
measurement, the voltage was above 230 V. So for a few days I logged
the voltage, and
found
it was consistently high. The maximum permitted here in the UK is
253 V, but I measured mine at 255.x volts. It was the heat of the
5370B that forced me to contact the electricity supply company (UK
Power Networks), who logged the voltage for 4 days. I have a 3-phase
supply here, which is unusual for a domestic property, but each of
the 3 phases was
consistently
high. I managed to get the supply company to reduce the voltage by 5%.
That
made a significant difference in the heatsink temperature of the
5370B, and a significant difference to to the exhaust temperature of
my HP 70000 series system.
I'm not saying an extra fan is not a good idea, but it is certainly
worth ensuring the mains voltage is not too high. I was told by UK
Power
Networks
that they aim for 245-250 V in rural areas - this is despite the UK
is supposed to be 230 -6%/+10%. On equipment with linear power
supplies, a
few
extra volts can lead to a significant increase in the amount of heat
the regulators produce. 10% extra voltage does not equate to 10%
extra
power
dissipation, but considerably more.
I found quite a reluctance on the part of the UK Power Networks to
reduce the voltage. Even though it was was on average more than 5%
high, the technical manager who took ownership of the problem only
wanted to reduce the voltage by 2.5%, despite they could easily
reduce it 5%. Luckily,
when
the engineers came to adjust the supply voltage, (which they do by
changing
the taps on the 11 kV primary), I managed to convince them that
there
were
very few properties on the transformer, and the furthest was an old
couple
that used very little electricity. So they did reduce it 5%, which
is the maximum they could. But they warned me that if there were
complaints of
low
voltage, they would have to increase it 2.5%. Luckily for me, nobody
locally noticed the reduction in mains voltage, and it is still on
average
over 230 V.
It would be interesting to know how low the AC input can go on a
5370B before the regulators fail to regulate. Given they are the
sort of instrument one might want to run for long periods, running
one on a UPS, with a transformer to reduce the output of the UPS,
might not be such a
bad
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Sent from my iPad 4.
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
David wrote:
For what it is worth, my 5370B run very hot, which forced me to check my
mains voltage * * *
it was consistently high. * * *
I managed to get the supply company to reduce the voltage by 5%.
Eliminating that small amount of extra dissipation won't get you
anywhere near the safe heatsink temperature zone with a 5370. I tested
one set for 120v with line voltages down to 90v (-25%), and the
heatsinks were still way too hot for comfort (both for your hand
touching them, and for peace of mind re: longevity).
It would be interesting to know how low the AC input can go on a 5370B
before the regulators fail to regulate.
The HP spec is +5, -10%. That includes a safety margin. -10% is not
the absolute minimum (where the supplies drop out of regulation). The
one I tested down to 90v was still in regulation at that voltage, but it
is possible the regulation might have been less effective at that
voltage than designed due to lack of sufficient regulator headroom. I'd
say you're most likely fine down to -20% or so, but test to make sure.
And note that there may well be some unit-to-unit variance.
Best regards,
Charles