Ayrton Shunt does double duty.
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
Pictures here:
http://www.qsl.net/k/k0ff/VOLT_NUTS/Ayrton_Shunt_Conversion/
Later I'll write it up and post it to that link as a PDF with text and
pictures, plus any subsequent modifications.
George Dowell
Much appreciated! I saw some of those units listed on eBay inexpensively and was curious about such a “mod”. Have you characterized it for tempco?
Sent from my iPhone
On Apr 30, 2018, at 2:02 PM, geoelectronics@rallstech.net wrote:
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
Pictures here:
http://www.qsl.net/k/k0ff/VOLT_NUTS/Ayrton_Shunt_Conversion/
Later I'll write it up and post it to that link as a PDF with text and
pictures, plus any subsequent modifications.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
No environmental chamber yet, have a Yokogawa controller and and an EIS
sensor simulator, going with a small box in the first for individual
components, but workload keeping me from completion of so many fun
projects. Now we are nearing grass cutting season here, the completion
of projects ratio will suffer.
George Dowell
On 2018/04/30 03:11 PM, jasonpepas@gmail.com wrote:
Much appreciated! I saw some of those units listed on eBay inexpensively and was curious about such a "mod". Have you characterized it for tempco?
Sent from my iPhone
On Apr 30, 2018, at 2:02 PM, geoelectronics@rallstech.net wrote:
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
Pictures here:
http://www.qsl.net/k/k0ff/VOLT_NUTS/Ayrton_Shunt_Conversion/
Later I'll write it up and post it to that link as a PDF with text and
pictures, plus any subsequent modifications.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
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and follow the instructions there.
Built a small temperature chamber using a Starbucks Refrigerator, Yokogawa Temperature controller, and PTC Heater (300 watt). It covers 0 degrees C to 55 degrees C and has an RS-485 interface to the PC. The compressor runs all the time, and the controller cycles the 300 watt heater as needed to stabilize the temperature. Here is a link to a YouTube video showing it:
Mitch
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of geoelectronics@rallstech.net
Sent: Monday, April 30, 2018 6:22 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Ayrton Shunt does double duty.
No environmental chamber yet, have a Yokogawa controller and and an EIS
sensor simulator, going with a small box in the first for individual
components, but workload keeping me from completion of so many fun
projects. Now we are nearing grass cutting season here, the completion
of projects ratio will suffer.
George Dowell
On 2018/04/30 03:11 PM, jasonpepas@gmail.com wrote:
Much appreciated! I saw some of those units listed on eBay inexpensively and was curious about such a "mod". Have you characterized it for tempco?
Sent from my iPhone
On Apr 30, 2018, at 2:02 PM, geoelectronics@rallstech.net wrote:
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
Pictures here:
http://www.qsl.net/k/k0ff/VOLT_NUTS/Ayrton_Shunt_Conversion/
Later I'll write it up and post it to that link as a PDF with text and
pictures, plus any subsequent modifications.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
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First class work there Mitch.
Did I see a ham radio?
73 DE K0FF
George Dowell
On 2018/04/30 09:19 PM, Mitch Van Ochten wrote:
Built a small temperature chamber using a Starbucks Refrigerator, Yokogawa Temperature controller, and PTC Heater (300 watt). It covers 0 degrees C to 55 degrees C and has an RS-485 interface to the PC. The compressor runs all the time, and the controller cycles the 300 watt heater as needed to stabilize the temperature. Here is a link to a YouTube video showing it:
Mitch
-----Original Message-----
From: volt-nuts [mailto:volt-nuts-bounces@febo.com] On Behalf Of geoelectronics@rallstech.net
Sent: Monday, April 30, 2018 6:22 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Ayrton Shunt does double duty.
No environmental chamber yet, have a Yokogawa controller and and an EIS
sensor simulator, going with a small box in the first for individual
components, but workload keeping me from completion of so many fun
projects. Now we are nearing grass cutting season here, the completion
of projects ratio will suffer.
George Dowell
On 2018/04/30 03:11 PM, jasonpepas@gmail.com wrote:
Much appreciated! I saw some of those units listed on eBay inexpensively and was curious about such a "mod". Have you characterized it for tempco?
Sent from my iPhone
On Apr 30, 2018, at 2:02 PM, geoelectronics@rallstech.net wrote:
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
Pictures here:
http://www.qsl.net/k/k0ff/VOLT_NUTS/Ayrton_Shunt_Conversion/
Later I'll write it up and post it to that link as a PDF with text and
pictures, plus any subsequent modifications.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there. _______________________________________________
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On Mon, 30 Apr 2018, 20:02 , geoelectronics@rallstech.net wrote:
Leeds and Northrup Ayrton Shunt box Model 2664.
Modified to do double duty as a precision resistor standard.
I must admit I don't know what the purpose of the original unit is. Perhaps
as part of a bridge given the galvanometer connections.
I know when I was looking to check out my HP 4284A precession LCR meter
(basic uncertainty of 0.05%) I was able to buy some 0.005% resistors in
some values. I think if trying to build a precision resistance box I would
look for resistors better than the 0.03% in there.
I wonder if you could go to much lower resistance values if you used the
galvanometer connections as sense wires. But maybe you are using it in a
way I don't understand. I only have my mobile phone now, so are not going
to search the web for more information.
Dave.
Hello Dave.
So far I have identified 3 different Leeds & Northrup "Boxes".
Originally my intention was to re-purpose the box, panel connectors and
switch for a project to make my own precision resistor banks.
All use different switches and vastly different resistors to achieve
their original purpose.
The subject of the first one is the "Ayrton (wired) Shunt Box". It was
used with a galvanometer as a sort of attenuator (current divider),
uniquely wired in the Ayrton fashion to insure the galvanometer was
always connected to a shunt resistor, even during switching. Think of
the scheme as a stepped potentiometer, the meter was between the two
extremes, while the source went to the wiper. Just backwards from a
Voltage divider.
Next is the "Shunt Box". It's resistors are copper straps, the lowest
value is made from a copper sheet maybe 5 inches wide, bent into a
corrugated shape to fit inside the box. Remarkable construction, should
be quite stable as a milliOhm standard.
The last one is called "Volt Box". Its resistors are wire wound on
ceramic forms, obviously with great care. The switch is protected and
possibly gold plated contacts. Multiple series connected resistors are
used to provide the correct values plus spread the current (heat load)
around, and they are spaced far apart and with air space around each
one. So far no clue as to its original function but of course I have
traced the schematic.
Very little is freely available on the 'net about them nor a period
catalog so far.
George Dowell
The volt box is likely to be a voltage divider that was used to divide a voltage to be measured down to a value within the measurement range of a L & N potentiometer (not the 3 terminal component but the type that sets up the current in a series string of resistors to a known vale by comparing the voltage across a subset with the voltage of a standard cell. The unknown voltage can then be measured by comparing it against the voltage drop across a adjustable subset of the series resistor string).
They are mentioned in various NBS (NIST) publications of the era as well as in various texts on dc electrical measurements. They were in common use up till around the 1980's.
Bruce
On 05 May 2018 at 01:55 geoelectronics@rallstech.net wrote:
Hello Dave.
So far I have identified 3 different Leeds & Northrup "Boxes".
Originally my intention was to re-purpose the box, panel connectors and
switch for a project to make my own precision resistor banks.
All use different switches and vastly different resistors to achieve
their original purpose.
The subject of the first one is the "Ayrton (wired) Shunt Box". It was
used with a galvanometer as a sort of attenuator (current divider),
uniquely wired in the Ayrton fashion to insure the galvanometer was
always connected to a shunt resistor, even during switching. Think of
the scheme as a stepped potentiometer, the meter was between the two
extremes, while the source went to the wiper. Just backwards from a
Voltage divider.
Next is the "Shunt Box". It's resistors are copper straps, the lowest
value is made from a copper sheet maybe 5 inches wide, bent into a
corrugated shape to fit inside the box. Remarkable construction, should
be quite stable as a milliOhm standard.
The last one is called "Volt Box". Its resistors are wire wound on
ceramic forms, obviously with great care. The switch is protected and
possibly gold plated contacts. Multiple series connected resistors are
used to provide the correct values plus spread the current (heat load)
around, and they are spaced far apart and with air space around each
one. So far no clue as to its original function but of course I have
traced the schematic.
Very little is freely available on the 'net about them nor a period
catalog so far.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nbsspecialpublication300v3.pdf
has a few articles on potentiometers and volt boxes.
F.K. Harris's Electrical measurements (1952) has further information.
Bruce
On 05 May 2018 at 09:36 Bruce Griffiths bruce.griffiths@xtra.co.nz wrote:
The volt box is likely to be a voltage divider that was used to divide a voltage to be measured down to a value within the measurement range of a L & N potentiometer (not the 3 terminal component but the type that sets up the current in a series string of resistors to a known vale by comparing the voltage across a subset with the voltage of a standard cell. The unknown voltage can then be measured by comparing it against the voltage drop across a adjustable subset of the series resistor string).
They are mentioned in various NBS (NIST) publications of the era as well as in various texts on dc electrical measurements. They were in common use up till around the 1980's.
Bruce
On 05 May 2018 at 01:55 geoelectronics@rallstech.net wrote:
Hello Dave.
So far I have identified 3 different Leeds & Northrup "Boxes".
Originally my intention was to re-purpose the box, panel connectors and
switch for a project to make my own precision resistor banks.
All use different switches and vastly different resistors to achieve
their original purpose.
The subject of the first one is the "Ayrton (wired) Shunt Box". It was
used with a galvanometer as a sort of attenuator (current divider),
uniquely wired in the Ayrton fashion to insure the galvanometer was
always connected to a shunt resistor, even during switching. Think of
the scheme as a stepped potentiometer, the meter was between the two
extremes, while the source went to the wiper. Just backwards from a
Voltage divider.
Next is the "Shunt Box". It's resistors are copper straps, the lowest
value is made from a copper sheet maybe 5 inches wide, bent into a
corrugated shape to fit inside the box. Remarkable construction, should
be quite stable as a milliOhm standard.
The last one is called "Volt Box". Its resistors are wire wound on
ceramic forms, obviously with great care. The switch is protected and
possibly gold plated contacts. Multiple series connected resistors are
used to provide the correct values plus spread the current (heat load)
around, and they are spaced far apart and with air space around each
one. So far no clue as to its original function but of course I have
traced the schematic.
Very little is freely available on the 'net about them nor a period
catalog so far.
George Dowell
volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
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