Member postings for Michael Gilligan

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Sit quietly with your beverage of choice, and read this: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=103028&p=1

MichaelG.

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Thanks for the confirmation ... I like that one.

Two-tone might indeed look good.

MichaelG.

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Thanks for replying, Neil

I am now happy that the problem is as I suspected : We were having two different conversations!

The real objection to the XLR connector and its lead is as I [hopefully] clarified in my post of 09:45:02 yesterday. ... It inevitably moves the cold junction to a point which is not monitored/normalised by the instrument.

MichaelG.

Very difficult to choose, when the same 'original colour' looks so different in the two photos.

... Would I be right in guessing that the second photo is more accurate ?

MichaelG.

Apologies if people are bored with this discussion:

This thread has just dropped off the first page, so I'm bumping it in the hope that Neil will see it again, and respond.

[ I simply don't understand your point, Neil; and that leaves me uncomfortable ]

MichaelG.

For the sake of undoing two screws, it might be worth releasing the circuit board and checking what's written on the chip ... These things are always easier when we've found a datasheet.

MichaelG.

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Possibly good for 0.75A ... so I would see how much it warms at 0.5A

**LINK**

https://en.m.wikibooks.org/wiki/Engineering_Tables/Standard_Wire_Gauge

MichaelG.

To be honest, John ... I think the best bet would be to build a scaled-up copy of the Pen Wizard [probably with something other than the simple mandrel].

There is a lot of information on their website !!

... and nothing wrong in making one for your own use.

MichaelG.

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Not that I can find ... but see if you can do any better;

the message came from Dr Hermes Haulage

MichaelG

A browse through currently available offerings might be a good start: **LINK**

https://uk.rs-online.com/web/c/power-supplies-transformers/transformers/variacs/?sra=p

Find something of similar weight and it will probably have a similar rating.

After that ... run some load tests and see when it starts to get warm.

MichaelG.

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Edit: Here is a Torovolt on ebay, for comparison

https://www.ebay.ie/itm/Variable-Transformer-240V-0-6A-Cressall-Torovolt-33Y-Variac-Unused-/192484445526

and a link to Cressall's web-site: https://www.cressall.com/about-us/

Edited By Michael Gilligan on 20/06/2018 14:20:37

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... and have received a preliminary response !

MichaelG.

Thanks, David ... I have just sent an eMail to Sam

MichaelG.

I've just spotted an interesting-looking upgrade to the RouterLathe: **LINK**

http://www.notjustround.com/Tools.html

MichaelG.

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Yes ... probably several, but the one most of us mentioned was the Trend RouterLathe.

[see p1 of this thread]

MichaelG.

Edited By Michael Gilligan on 20/06/2018 11:30:10

Sorry, I can't help Keith

But I'm bumping this thread to stop it dropping off the bottom of the page.

They do look delightful machines: **LINK**

http://www.lathes.co.uk/cataract/

Some photos of what you have would be interesting.

MichaelG.

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Before you ask how to post images:

https://www.model-engineer.co.uk/forums/postings.asp?th=103028&p=1

Edited By Michael Gilligan on 19/06/2018 18:52:23

As we are now well into p3 and still struggling ... I would just like to re-state the issue:

• The Schematic Fig.2 [not Fig.1] shows the Thermocouple correctly connected to terminals 9 & 10 of the PID Controller.
• The controller will treat those terminals as the reference junction[s], and will presumably have a local correction device to normalise it to a 'cold junction'. .... Please see the Wikipedia page for a picture of how this is done on a Fluke meter.
• Chris Gabel has, for convenience, added an extension lead of 'thin gauge stranded wire' and an XLR connector, which moves the actual cold reference junction 'outside' his ABS box.
• The temperature at the controller's 'cold junction' correction point is therefore not tied to that of the actual cold junction.
• If the extension lead had simply been made of thermocouple extension wire and a matched plug and socket, this invitation to error would not exist.

MichaelG.

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https://en.wikipedia.org/wiki/Thermocouple#/media/File:Cold_Junction_Compensation_with_Thermistor_to_measure_the_junction_temperature..jpg

Edited By Michael Gilligan on 19/06/2018 09:47:53

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Then could you please explain your point [either here or privately], because we appear to be having different conversations.

MichaelG.

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Edit: I am particularly keen to understand why you made this obvious but irrelevant statement:

"If you connect the two wires at both ends, you won't have any voltage to measure..."

Edited By Michael Gilligan on 19/06/2018 09:08:17

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We are, I'm sure, in agreement !!

MichaelG.

Edited By Michael Gilligan on 18/06/2018 23:00:55

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Perhaps this is a more helpful diagram:

**LINK**

http://enacademic.com/pictures/enwiki/84/Thermocouple_circuit.svg

MichaelG.

John,

I've just been browsing around, and found this page: **LINK**

https://stusshed.com/tag/beall/

The first couple of pictures are another [perhaps the original?] routerlathe-style device ... but then it gets more interesting: Maybe sufficient to get your inventive streak going.

MichaelG.

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Edit: Here is Beall's website: 

http://www.bealltool.com/products/penwizard/penwiz.php

Where you will find detailed instructions and some excellent photographs 

Edited By Michael Gilligan on 18/06/2018 21:41:20