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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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23rd May 2020, 4:42 pm | #1 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Manganin coil resistance box by Pye and Co
This arrived today. I'll test it later, but screws have not been tampered with, so should have original coils.
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24th May 2020, 11:52 pm | #2 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Manganin coil Brige by Pye and Co
Looks like a resistance box, not a bridge though it could be used as part of a bridge circuit if you wanted. Manganin has a decently low TCR too.
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25th May 2020, 10:50 am | #3 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Re: Manganin coil Brige by Pye and Co
You are totally right, variable resistance box, I would have to add it in a tiny circuit, but you're right.
I'll try it this week, I'll get the room to 17 centigrade and it should give great accuracy. I'm tempted to open it. Screws look untouched so maybe best left alone. The same goes for restoring the top, where it has lost some shine, due to use. |
25th May 2020, 11:41 am | #4 |
Octode
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,733
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Re: Manganin coil resistance box by Pye and Co
Here is the Pye Wheatstone bridge I have, it looks a bit later then your resistance decade box, but has the same style controls for the Manganin coils.
David |
25th May 2020, 10:20 pm | #5 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Re: Manganin coil resistance box by Pye and Co
Got to get one of those...love it. Mint inside. Was it expensive?
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26th May 2020, 1:10 am | #6 |
Heptode
Join Date: Oct 2009
Location: Melbourne Australia
Posts: 901
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Re: Manganin coil resistance box by Pye and Co
I have a PYE 7440/G wheatsone as well. It was interesting to check how the coil resistances had aged over the last 70 years or so. It seems that the 1kohm resistors have had a harder time of it, given they use the finest gauge wire, and may have been exposed to the highest power loss during equipment use.
https://www.dalmura.com.au/static/PY...dge%207440.pdf |
26th May 2020, 10:06 pm | #7 |
Octode
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,733
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Re: Manganin coil resistance box by Pye and Co
Will have to investigate to see if the resistances have aged, thanks for the link to the manual, I couldn't find anything like that when I searched a while back.
I also got a single Pye Manganin resistance at .1 ohm along with a selection of decade resistors & capacitors and a couple of meters from other makes. There was another similar Pye resistance (different value) but someone bought it before me. All of these were from Southampton University. I can't remember how much they cost, but I did make a note, just can't find it. David |
26th May 2020, 11:59 pm | #8 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Manganin coil resistance box by Pye and Co
That's a nice four terminal shunt you have there!
It would be interesting to know what its max current rating is.
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....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |
27th May 2020, 7:02 am | #9 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,662
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Re: Manganin coil resistance box by Pye and Co
"It would be interesting to know what its max current rating is. " 13A, bottom RH corner Chris.
Andy.
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27th May 2020, 11:37 am | #10 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Re: Manganin coil resistance box by Pye and Co
I just tried mine. At first meter was all over the place. Just twiddled the knobs and it settled and was spot on. Must be dirt or something sticking. It is about 100 years old, probably has not been used much lately. But outstanding quality. Out at higher values but seems to get better as I use the knobs?
Last edited by Mr Etronic; 27th May 2020 at 12:01 pm. |
27th May 2020, 12:02 pm | #11 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Re: Manganin coil resistance box by Pye and Co
A few results.
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29th May 2020, 11:27 pm | #12 |
Octode
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 1,733
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Re: Manganin coil resistance box by Pye and Co
Well mine seems to check out good as a resistance box (one of the uses in the manual), I was going to use a 4.5 digit meter but it didn't want to work (intermittent fault).
David |
31st May 2020, 1:56 am | #13 |
Triode
Join Date: May 2020
Location: Caernarfon, Wales, UK.
Posts: 46
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Re: Manganin coil resistance box by Pye and Co
Yours looks pretty damn flash.
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31st May 2020, 3:49 pm | #14 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Manganin coil resistance box by Pye and Co
So it is. Had to peer closely though- it says .1 OHM in the bottom RH corner
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....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |