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Need a calculator that knows about coulombs

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  Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 02:20 +0100
    Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 02:40 +0100
    Re: Need a calculator that knows about coulombs Jimmy Johnson <jimmyjhn@gmail.com> - 2015-12-23 02:40 +0100
      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 02:50 +0100
        Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-23 03:10 +0100
          Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 11:10 +0100
            Re: Need a calculator that knows about coulombs Joe <joe@jretrading.com> - 2015-12-23 12:50 +0100
              Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 16:10 +0100
            Re: Need a calculator that knows about coulombs David Christensen <dpchrist@holgerdanske.com> - 2015-12-23 19:30 +0100
              Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-23 20:10 +0100
              Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 20:20 +0100
                Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-23 20:40 +0100
                  Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 22:20 +0100
                    Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-24 01:30 +0100
                      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 02:40 +0100
                  Re: Need a calculator that knows about coulombs Bob Bernstein <poobah@ruptured-duck.com> - 2015-12-24 02:10 +0100
                    Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-24 02:40 +0100
                      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 03:00 +0100
                        Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-24 03:20 +0100
                          Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 04:50 +0100
                    Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 02:50 +0100
                      Re: Need a calculator that knows about coulombs Bob Bernstein <poobah@ruptured-duck.com> - 2015-12-24 03:10 +0100
                        Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 04:40 +0100
                    Re: Need a calculator that knows about coulombs Lisi Reisz <lisi.reisz@gmail.com> - 2015-12-24 12:30 +0100
                      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 16:40 +0100
          Re: Need a calculator that knows about coulombs Gary Roach <gary719_list1@verizon.net> - 2015-12-24 01:00 +0100
            Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-24 01:40 +0100
              Re: Need a calculator that knows about coulombs Anders Andersson <pipatron@gmail.com> - 2015-12-24 01:40 +0100
            Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-24 02:40 +0100
        Re: Need a calculator that knows about coulombs David Christensen <dpchrist@holgerdanske.com> - 2015-12-23 03:20 +0100
          Re: Need a calculator that knows about coulombs Bob Bernstein <poobah@ruptured-duck.com> - 2015-12-23 04:40 +0100
            Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 11:50 +0100
          Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 11:40 +0100
            Re: Need a calculator that knows about coulombs David Christensen <dpchrist@holgerdanske.com> - 2015-12-23 19:40 +0100
    Re: Need a calculator that knows about coulombs rlharris@oplink.net - 2015-12-23 02:40 +0100
    Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-23 03:00 +0100
      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 11:40 +0100
    Re: Need a calculator that knows about coulombs Charlie Kravetz <cjk@teamcharliesangels.com> - 2015-12-23 04:50 +0100
    Re: Need a calculator that knows about coulombs Jörg-Volker Peetz <jvpeetz@web.de> - 2015-12-23 15:00 +0100
      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-23 16:20 +0100
        Re: Need a calculator that knows about coulombs Jörg-Volker Peetz <jvpeetz@web.de> - 2015-12-28 10:40 +0100
          Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-28 14:00 +0100
            Re: Need a calculator that knows about coulombs John Hasler <jhasler@newsguy.com> - 2015-12-28 18:40 +0100
              Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-28 21:00 +0100
    Re: Need a calculator that knows about coulombs Gener Badenas <gener.ong.badenas@gmail.com> - 2015-12-28 08:10 +0100
      Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-28 13:20 +0100
        Re: Need a calculator that knows about coulombs Joel Rees <joel.rees@gmail.com> - 2015-12-29 09:40 +0100
          Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-29 10:50 +0100
        Re: Need a calculator that knows about coulombs Joel Rees <joel.rees@gmail.com> - 2015-12-29 12:00 +0100
          Re: Need a calculator that knows about coulombs Joel Rees <joel.rees@gmail.com> - 2015-12-29 12:10 +0100
            Re: Need a calculator that knows about coulombs Gene Heskett <gheskett@shentel.net> - 2015-12-29 16:50 +0100
      Re: Need a calculator that knows about coulombs ken <gebser@mousecar.com> - 2016-01-03 12:00 +0100

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#162010 — Need a calculator that knows about coulombs

Greetings all;

Do we have such a beast?

Thanks.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Some mill pix are at:
Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix>

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#162011

On Tuesday 22 December 2015 20:31:50 rlharris@oplink.net wrote:

> On Tue, December 22, 2015 7:09 pm, Gene Heskett wrote:
> > Re: Need a calculator that knows about coulombs
>
> Look for "Weber" as well as for "Coulumb".
>
> Russ

That too is a new term to me, how does it translate?

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Some mill pix are at:
Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix>

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#162013

On 12/22/2015 05:09 PM, Gene Heskett wrote:
> Greetings all;
>
> Do we have such a beast?
>
> Thanks.
>
> Cheers, Gene Heskett


Free on the web: http://www.endmemo.com/physics/coulomb.php
-- 
Debian Jessie - KDE 4.14.2  - EXT4 - AMD64 at sda10
Registered Linux User #380263

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#162015

On Tuesday 22 December 2015 20:17:58 Jimmy Johnson wrote:

> On 12/22/2015 05:09 PM, Gene Heskett wrote:
> > Greetings all;
> >
> > Do we have such a beast?
> >
> > Thanks.
> >
> > Cheers, Gene Heskett
>
> Free on the web: http://www.endmemo.com/physics/coulomb.php

That might be interesting, but at first glance, is not applicable to what 
I want to experiment with. In this case, the size of a capacitor hooked 
to a square wave source, and I want to know how much charge is 
transfered for every full cycle of the input square wave.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Some mill pix are at:
Genes Web page <http://geneslinuxbox.net:6309/gene/GO704-pix>

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#162018

Gene Heskett writes:
> In this case, the size of a capacitor hooked to a square wave source,
> and I want to know how much charge is transfered for every full cycle
> of the input square wave.

Zero assuming linear source and load impedence.
-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162026

On Tuesday 22 December 2015 21:02:31 John Hasler wrote:

> Gene Heskett writes:
> > In this case, the size of a capacitor hooked to a square wave
> > source, and I want to know how much charge is transfered for every
> > full cycle of the input square wave.
>
> Zero assuming linear source and load impedence.

Ahh, but its being fed to a voltage-doubler with schottky diodes, so 
there should be a calculatable amount of charge delivered to the output 
capacitor Cf, by the pump capacitor Cp, per cycle.  With Cp being of a 
capacity such that with the usual logic circuits output impedance, 
capable of delivering 10 to 20 milliamps into a resistive load, IOW not 
a zero impedance source. Cf would be sized such as to be about 50x Cp, 
and will be driving an enhancement mode fet which will turn on a 40 amp 
SSR once the charge has built up on Cf to make the fet conduct.

A charge pump detector to control a 2 kw DC power supply startup, one 
turning it on but with a 51 ohm 200 watt resistor in series with the AC 
line, and another identical circuit turning on a 2nd 40 amp SSR to short 
circuit the 51 ohm 200 watt resistor but timed to be 5 seconds later, 
after the capacitors are charged up.  The PSU has a quite high 
capacitance input filter, and without this soft start timed power up, 
needs a 30 amp breaker in the service in order for the breaker to 
withstand the power up event. NEC says I can't service a duplex with 
more than a 15 amp breaker.  The actual draw, once powered up, doesn't 
exceed 15 amps even with a vacuum cleaner being powered by a similar 
circuit enabled that is plugged into this same 4-plex.

All part of a CNC milling machine setup.  And theres no reason for it to 
be enabled when the CNC control program isn't running.  The program will 
generate the 500 hz square wave these charge pump detectors will detect, 
and will control the time delay for the 2nd one. 1/4 to 1 second 
response time is not a concern for something like this.  It just needs 
to be 101% dependable. :)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162035

On Wed, 23 Dec 2015 05:09:18 -0500
Gene Heskett <gheskett@shentel.net> wrote:

> On Tuesday 22 December 2015 21:02:31 John Hasler wrote:
> 
> > Gene Heskett writes:  
> > > In this case, the size of a capacitor hooked to a square wave
> > > source, and I want to know how much charge is transfered for every
> > > full cycle of the input square wave.  
> >
> > Zero assuming linear source and load impedence.  
> 
> Ahh, but its being fed to a voltage-doubler with schottky diodes, so 
> there should be a calculatable amount of charge delivered to the
> output capacitor Cf, by the pump capacitor Cp, per cycle.  With Cp
> being of a capacity such that with the usual logic circuits output
> impedance, capable of delivering 10 to 20 milliamps into a resistive
> load, IOW not a zero impedance source. Cf would be sized such as to
> be about 50x Cp, and will be driving an enhancement mode fet which
> will turn on a 40 amp SSR once the charge has built up on Cf to make
> the fet conduct.
> 
>
Do it numerically with a spreadsheet.

It takes a while with any reasonably-sized spreadsheet, but you can
trust the result, you can see every stage and can spot anything
obviously wrong.

I once needed to analyse the start-up surge into a large capacitance
using a toroidal mains transformer, and given the non-linearity of the
rectifiers, I could see no other way. When results can reach hundreds of
amps for a millisecond or so, you don't want large piecewise-linear
approximations.

-- 
Joe

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#162045

On Wednesday 23 December 2015 06:47:39 Joe wrote:

> On Wed, 23 Dec 2015 05:09:18 -0500
>
> Gene Heskett <gheskett@shentel.net> wrote:
> > On Tuesday 22 December 2015 21:02:31 John Hasler wrote:
> > > Gene Heskett writes:
> > > > In this case, the size of a capacitor hooked to a square wave
> > > > source, and I want to know how much charge is transfered for
> > > > every full cycle of the input square wave.
> > >
> > > Zero assuming linear source and load impedence.
> >
> > Ahh, but its being fed to a voltage-doubler with schottky diodes, so
> > there should be a calculatable amount of charge delivered to the
> > output capacitor Cf, by the pump capacitor Cp, per cycle.  With Cp
> > being of a capacity such that with the usual logic circuits output
> > impedance, capable of delivering 10 to 20 milliamps into a resistive
> > load, IOW not a zero impedance source. Cf would be sized such as to
> > be about 50x Cp, and will be driving an enhancement mode fet which
> > will turn on a 40 amp SSR once the charge has built up on Cf to make
> > the fet conduct.
>
> Do it numerically with a spreadsheet.
>
> It takes a while with any reasonably-sized spreadsheet, but you can
> trust the result, you can see every stage and can spot anything
> obviously wrong.
>
> I once needed to analyse the start-up surge into a large capacitance
> using a toroidal mains transformer, and given the non-linearity of the
> rectifiers, I could see no other way. When results can reach hundreds
> of amps for a millisecond or so, you don't want large piecewise-linear
> approximations.

True, but all I am interested in, and the transformers involved are 
toroids, 4 of them good for half a kw each, is limiting the input surge 
to 127/51=2.49019607843 amps at the initial turn on with the 51 ohm R in 
series with their combined primaries.  Then however many seconds later 
when those caps are at 90% or better charge and long before I or the 
code starts the spindle, shorts the 51 ohm resistor allowing full 
current flow.  It could be in excess of a minute because the first 
operation is homing the machine, one axis at a time, which depending on 
where it was when last powered down, could take up to a full minute to 
do. The spindle power at full song is not a requirement until that is 
done.  And because of the acoustic noise from both the spindle and 
vacuum, I don't normally start the spindle and vacuum until it is in 
position to start cutting with the next commanded move. I am the one 
writing the code.

So I don't need to analyse it microsecond by microsecond, just control it 
to a defined peak current draw. In this case I could use a lower 
resistor value R but thats what I have available in my "junk box" 
without ordering online.  It will catch 316.254901961 instant watts when 
the caps are at 0 volts, more than its 200 watt rating, but not for long 
enough to blow the glaze off it over time as that instantaineous power 
will drop rapidly as the caps charge up to working voltage.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162052

On 12/23/2015 02:09 AM, Gene Heskett wrote:
> Ahh, but its being fed to a voltage-doubler with schottky diodes ...
> The PSU has a quite high
> capacitance input filter, and without this soft start timed power up,
> needs a 30 amp breaker in the service in order for the breaker to
> withstand the power up event. NEC says I can't service a duplex with
> more than a 15 amp breaker.  The actual draw, once powered up, doesn't
> exceed 15 amps even with a vacuum cleaner being powered by a similar
> circuit enabled that is plugged into this same 4-plex.
> All part of a CNC milling machine setup. ...

So, you want to connect a 120 VAC, 30 A CNC milling machine and a 120 
VAC, unknown current vacuum cleaner to a single 120 V 15 A branch circuit.


I suppose you could read a power electronics book, and design and build 
a device that accepts 120 VAC, 15 A steady-state input and provides 120 
VAC, 15 A steady-state output with the ability to output much more 
current for short periods.  Such a product may already exist.  If not, 
you might be able to make and sell them.


But, the KISS solution is obvious -- install a 30 ampere circuit 
breaker, wiring, and receptacle for the CNC machine (or hire an 
electrician to do so).


David

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#162056

David writes:
> So, you want to connect a 120 VAC, 30 A CNC milling machine and a 120
> VAC, unknown current vacuum cleaner to a single 120 V 15 A branch
> circuit.

No.  He wants to power a 16A mill.  His problem is high inrush on
startup of a DC supply.  Soft-start is a reasonable way to solve it.  He
should use a 20A breaker, though.  15A receptacles are ok on 20A
circuits (though I'd use 20A receptacles and plugs here).

The 2kW is probably peak load.
-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162058

On Wednesday 23 December 2015 13:22:14 David Christensen wrote:

> On 12/23/2015 02:09 AM, Gene Heskett wrote:
> > Ahh, but its being fed to a voltage-doubler with schottky diodes ...
> > The PSU has a quite high
> > capacitance input filter, and without this soft start timed power
> > up, needs a 30 amp breaker in the service in order for the breaker
> > to withstand the power up event. NEC says I can't service a duplex
> > with more than a 15 amp breaker.  The actual draw, once powered up,
> > doesn't exceed 15 amps even with a vacuum cleaner being powered by a
> > similar circuit enabled that is plugged into this same 4-plex.
> > All part of a CNC milling machine setup. ...
>
> So, you want to connect a 120 VAC, 30 A CNC milling machine and a 120
> VAC, unknown current vacuum cleaner to a single 120 V 15 A branch
> circuit.
>
>
> I suppose you could read a power electronics book, and design and
> build a device that accepts 120 VAC, 15 A steady-state input and
> provides 120 VAC, 15 A steady-state output with the ability to output
> much more current for short periods.  Such a product may already
> exist.  If not, you might be able to make and sell them.
>
>
> But, the KISS solution is obvious -- install a 30 ampere circuit
> breaker, wiring, and receptacle for the CNC machine (or hire an
> electrician to do so).

I am a CET. I do my own wiring on small projects. I even put a 200 amp 
service in here back in 2007 or so, putting the house as a subcircuit. 
The only thing I needed an electrician for was to do the drop seal break 
& disconnect, install a heavier drop to the new meterhead, the inspector 
came, liked what he saw and signed off, dead time to crimping the new 
seal a couple hours.  Besides, powered up, spindle turning no load at 
500 revs, the amprobe draw (w/o the vacuum) is around 2.65 amps, on 
either amprobe, I have 2.

Its just the inrush that needs curtailed. Once thats done I'll swap the 
30A breaker back out for a 20A I have laying there ready to be put back 
in where it came out.
>
> David

And Qucs is still building.  Sigh.
Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162060

Gene H writes:
> The only thing I needed an electrician for was to do the drop seal
> break & disconnect, install a heavier drop to the new meterhead, the
> inspector came...

Electricians, permits and inspectors eh?  I guess when you have
oppressive government you just have to live with these things.  I redid
the farm with buried cable and put in a new service and all I had to do
was give Excel a written assertion that I had complied with code.
-- 
John "Permits?  We don't need no stinkin permits." Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162063

On Wednesday 23 December 2015 14:33:39 John Hasler wrote:

> Gene H writes:
> > The only thing I needed an electrician for was to do the drop seal
> > break & disconnect, install a heavier drop to the new meterhead, the
> > inspector came...
>
> Electricians, permits and inspectors eh?  I guess when you have
> oppressive government you just have to live with these things.  I
> redid the farm with buried cable and put in a new service and all I
> had to do was give Excel a written assertion that I had complied with
> code.

Here in Wv, jumper cables across the meter socket have been a problem, so 
a broken seal on the meters retaining ring is a felony. Its also a 
felony in several other states I have lived and worked in.

But to my knowledge, the NEC code has only been in effect since the later 
80's. You would be aghast at some stuff thats grandfathered in, lioke 
our old transmitter site. 4 pieces of 750mcm alu come from the 
substation pole, with no building disconnect between them and the hot 
side of a GE AK-225 3 phase plate breaker/relay, which feeds a 50kw 
transformer delivering a rectified 7200 volts for the transmitters final 
amplifiers.  We've burned out that 750 mcm and the entry weatherhead 
twice on my watch because Burndy can't make a crimp sleeve for that size 
that maintains a 'gas tight' connection to an alu cable over the years. 
Its the power companies cable, but copper costs lots more so they will 
just replace it when it gets cooked. The list at that site goes on, but 
its now retired and the only power on is for the tower lights, still 
required.

This house, build as a kit by National Homes in 1975, is not and never 
will be 100% compliant to the NEC.  When we had an extra fire door 
installed as an escape route in the back bedroom, I had the installer 
add a duplex on each side of it because every other duplex in the whole 
house is mid-wall and totally in-accessible without moving hundreds of 
lbs of furniture. Just to plug in the vacuum cleaner?  Screw 'em, I'll 
put them where they CAN be used. Its paid for, all ours, and well 
insured.  I treat it like it was Los Vegas, what happens here, stays 
here.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162067

Gene H writes:
> Here in Wv, jumper cables across the meter socket have been a problem,
> so a broken seal on the meters retaining ring is a felony. Its also a
> felony in several other states I have lived and worked in.

Well, sure.  When I rewired the farm with buried cable and put in the
new service and meter socket the Excel guys who plowed in the
underground drop plugged in the new meter and put on a seal.  This was
all coordinated with the re-routing of their feeder from across my farm
to along the road.  Breaking the seal is not, in and of itself, a crime
here, though.  Jumpering the meter is theft, of course.
-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162074

On Wednesday 23 December 2015 19:25:40 John Hasler wrote:

> Gene H writes:
> > Here in Wv, jumper cables across the meter socket have been a
> > problem, so a broken seal on the meters retaining ring is a felony.
> > Its also a felony in several other states I have lived and worked
> > in.
>
> Well, sure.  When I rewired the farm with buried cable and put in the
> new service and meter socket the Excel guys who plowed in the
> underground drop plugged in the new meter and put on a seal.  This was
> all coordinated with the re-routing of their feeder from across my
> farm to along the road.  Breaking the seal is not, in and of itself, a
> crime here, though.  Jumpering the meter is theft, of course.

Which all boils down to "when in Rome..." ;-)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162070

On Wed, 23 Dec 2015, John Hasler wrote:

> John "Permits?  We don't need no stinkin permits." Hasler

Reminds me of "Don't RTFM! Wing that sucker!"

Haven't heard/seen that in a long time.

And I have to say, this electrical stuff is a lot sexier than 
poopy linux stuff!

-- 
Bob Bernstein

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#162073

Bob Bernstein writes:
> And I have to say, this electrical stuff is a lot sexier than poopy
> linux stuff!

I could bore you to tears in 15 minutes with anecdotes about hospital
wiring design.
-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162077

On Wednesday 23 December 2015 20:33:57 John Hasler wrote:

> Bob Bernstein writes:
> > And I have to say, this electrical stuff is a lot sexier than poopy
> > linux stuff!
>
> I could bore you to tears in 15 minutes with anecdotes about hospital
> wiring design.

Having read some of the extra's for that, its no wonder the bid estimates 
are 400% of what the takeoff guy totals up.  And my little red pocket 
hot wire sniffer still manages to go berzerk when within sensing 
distance to some of the innocent looking stuff sitting on the prep rooms 
counters.  I found 4 of those flashlight things they put a plastic cup 
over to look into an ear, that could be lethal so far.  All maintained 
by some contractor & the Doc his self was powerless to do anything about 
it.  Scary, tain't it?

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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#162079

Gene H writes:
> Having read some of the extra's for that, its no wonder the bid
> estimates are 400% of what the takeoff guy totals up.

We had an in-house construction operation for small projects of the sort
I designed.  They were mostly pretty good but my biggest problems came
from their attempts to save money, such as using left-over 90 ohm IT
coax for a CATV project instead of the 70 cable I had specified.  The
hospital was horribly mismanaged, though.

> And my little red pocket hot wire sniffer still manages to go berzerk
> when within sensing distance to some of the innocent looking stuff
> sitting on the prep rooms counters.  I found 4 of those flashlight
> things they put a plastic cup over to look into an ear, that could be
> lethal so far.

No, not really.  That devices is only useful for finding energized wires
behind walls.  It tells you nothing about lethality.  All sorts of
harmless things can set it off.
-- 
John Hasler 
jhasler@newsguy.com
Elmwood, WI USA

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#162082

On Wednesday 23 December 2015 21:19:33 John Hasler wrote:

> Gene H writes:
> > Having read some of the extra's for that, its no wonder the bid
> > estimates are 400% of what the takeoff guy totals up.
>
> We had an in-house construction operation for small projects of the
> sort I designed.  They were mostly pretty good but my biggest problems
> came from their attempts to save money, such as using left-over 90 ohm
> IT coax for a CATV project instead of the 70 cable I had specified. 
> The hospital was horribly mismanaged, though.
>
> > And my little red pocket hot wire sniffer still manages to go
> > berzerk when within sensing distance to some of the innocent looking
> > stuff sitting on the prep rooms counters.  I found 4 of those
> > flashlight things they put a plastic cup over to look into an ear,
> > that could be lethal so far.
>
> No, not really.  That devices is only useful for finding energized
> wires behind walls.  It tells you nothing about lethality.  All sorts
> of harmless things can set it off.

My final test for potential lethality is to make sure I am insulated, 
then brush the back of my hand against it very gently. If it feels like 
it is vibrating as the back of your hand slides against it, its too hot 
to get between it and a grounded object.

The back of ones hand is amazingly sensitive to that sort of thing, and 
it might save your life to remember that, everybody reading this.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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