Latest Acquisition and it's mint.

[telectrix]

H.W,Sullivan, type of Wheatstone Bridge . Son found it on faceache or some other anti-social gossip site. £15. Guess it's age to be about 80 -90 years. Lucien would have been able to give me some info., like what voltage battery etc, but any info appreciated.

Google tells me that the company was founder in 1897 , manufacturing telegraph machines.
.,

 

[snowhead]

Looks like the meter has been "upgraded" on yours Tel,

V126 4.5v battery from the link below, unless your has been modded for 4 x "C" cell as pic below.

John's Virtual Museum - Decade Bridge 43379

This is a 4-decade Wheatstone bridge with ranges from 10 ohm to 10 megohm full-scale. The unit has been modified at some time to take four "C" cells instead of the original 4.5 V 126 battery. Intriguingly, it suggests that a 225 V battery is required for the 10 megohm range. The detector isn't

sites.google.com

A6570 (Ever Ready No. 126 replacement) 4.5V 'Box Battery' (A6570, Hercules HS6570G, 3LR12, 3LR20, 126) 4.5V Box Battery.

 

[telectrix]

Looks like the meter has been "upgraded" on yours Tel,

V126 4.5v battery from the link below, unless your has been modded for 4 x "C" cell as pic below.

John's Virtual Museum - Decade Bridge 43379

This is a 4-decade Wheatstone bridge with ranges from 10 ohm to 10 megohm full-scale. The unit has been modified at some time to take four "C" cells instead of the original 4.5 V 126 battery. Intriguingly, it suggests that a 225 V battery is required for the 10 megohm range. The detector isn't

sites.google.com

A6570 (Ever Ready No. 126 replacement) 4.5V 'Box Battery' (A6570, Hercules HS6570G, 3LR12, 3LR20, 126) 4.5V Box Battery.

View attachment 109312

only problem is it's listed as "out of stock".

 

[snowhead]

only problem is it's listed as "out of stock".

It was just an example.
I thought you'd go for the budget option of converting to 3 x C (not 4 as I put earlier)

 

[telectrix]

ordered a 4.5V flat bugger , like wtah you had in a bicycle front lamp in the 60's,if we ever bothered with lights back then.no lights on bike made it harder for the bizzies to find us.

 

[timhoward]

Very nice!
As you probably gathered it can measure resistances very accurately. Usually as accurately if not more accurately than a modern MFT. It can also do Murray loop tests to predict where a fault is.

Basically if a cable is faulting to earth, you join the conductors at the far end and measure the resistance as usual.
Then you'd switch to "Murray Loop", and the negative battery terminal would presumably need connecting to a good earth.
You'd then measure again. From these two values, and the formula in the manual, the distance along the line that the fault is can be calculated.

A Megger BR4 manual (which I found online as I have one) would fill in some of the blanks about the concepts.

 

[telectrix]

fitted a 4.5V battery. sadly, no matter what I do with dials and switches, there's no response from the galvanometer: stuck on 0. it's not locked as the zero adjust moves the needle. going to open the box and see if there's anything glaring,

 

[timhoward]

fitted a 4.5V battery. sadly, no matter what I do with dials and switches, there's no response from the galvanometer: stuck on 0. it's not locked as the zero adjust moves the needle. going to open the box and see if there's anything glaring,

The most likely is that the galvanometer has become damaged.
As it's removable you could try testing it directly by cooking up something like this.

Make resistors P, Q, and R the same and S about half the value. It should move.
Or just stick an AA battery across it!

 

[timhoward]

PS, if anyone else wants to join the bridge tester party, there's another similar one here:

Vintage Galvanometer L&N Leeds & Northrup Type S Test Set No. 5300 in Case | eBay

Find many great new & used options and get the best deals for Vintage Galvanometer L&N Leeds & Northrup Type S Test Set No. 5300 in Case at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[DPG]

PS, if anyone else wants to join the bridge tester party, there's another similar one here:

Vintage Galvanometer L&N Leeds & Northrup Type S Test Set No. 5300 in Case | eBay

Find many great new & used options and get the best deals for Vintage Galvanometer L&N Leeds & Northrup Type S Test Set No. 5300 in Case at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

Nice example that.

 

[telectrix]

The most likely is that the galvanometer has become damaged.
As it's removable you could try testing it directly by cooking up something like this.

View attachment 109363

Make resistors P, Q, and R the same and S about half the value. It should move.
Or just stick an AA battery across it!

going to open it up tomorrow - see what's what. will gry above first option.

 

[RDB85]

H.W,Sullivan, type of Wheatstone Bridge . Son found it on faceache or some other anti-social gossip site. £15. Guess it's age to be about 80 -90 years. Lucien would have been able to give me some info., like what voltage battery etc, but any info appreciated.

Google tells me that the company was founder in 1897 , manufacturing telegraph machines.
.,

A bargain indeed if the below is anything to go by:

Vintage H. W. Sullivan Decade Bridge tester, type 43379 wooden box | eBay

Find many great new & used options and get the best deals for Vintage H. W. Sullivan Decade Bridge tester, type 43379 wooden box at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[telectrix]

A bargain indeed if the below is anything to go by:

Vintage H. W. Sullivan Decade Bridge tester, type 43379 wooden box | eBay

Find many great new & used options and get the best deals for Vintage H. W. Sullivan Decade Bridge tester, type 43379 wooden box at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

that is identical to mine. same model number. 43379.

 

[telectrix]

update.. opened it up and found this. galvo has deffo been updated as it has a PCB and on it there's a 8 legged microchip. there's 2 sets if leads coming off ending in 2 PP£ connectors, but no connection to the internals of the machine, and no apparent place for them to go. pointless fitting PP3/s as would just be a stand alone galvanometer . Any ideas???

 

[telectrix]

further investigation finds that the 2 securing release pillars for the galvo are actually terminals, connected to both the galvo and the internal resistor banks. tomorrow will try and see if connecting 2 PP3s will get some life into it. if i read it right, maybe someone has modded it to use PP3s instead of the original battery, necessitating the removal of the meter to replace said batteries. weird.