Re: [time-nuts] External cooling fans - source

[Charles Steinmetz]

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


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Re: [time-nuts] External cooling fans - source

[Van Horn, David]

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-boun...@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 <kb...@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 <
> drkir...@kirkbymicrowave.co.uk> wrote:
> >
> > On 18 December 2017 at 23:11, Charles Steinmetz 
> > <csteinm...@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 7 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%.

Re: [time-nuts] External cooling fans - source

[Jeremy Nichols]

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  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 <
> drkir...@kirkbymicrowave.co.uk> wrote:
> >
> > On 18 December 2017 at 23:11, Charles Steinmetz 
> > 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 7
> > 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.
>
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> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
-- 
Sent from my iPad 4.

Re: [time-nuts] External cooling fans - source

[Bob kb8tq]

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 
>  wrote:
> 
> On 18 December 2017 at 23:11, Charles Steinmetz 
> 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 7
> 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
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Re: [time-nuts] External cooling fans - source

[Dr. David Kirkby]

On 18 December 2017 at 23:11, Charles Steinmetz 
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 7
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
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