Found in a cupboard

[Boac]

Anyone think these items are of 'historic' worth? Not sure what the first one is but it has a crank handle on the side: both German.

[Rossian]

.....could it be an older form of "megger"? Ein Deutche megger?

The Ancient Mariner

[Boac]

That's what I wunnerd, Sir. Is it for the bin?

[k3k3]

There are people who collect, and pay good money for, all sorts of stuff.

Put it on Ebay and see what happens.

[Wodrick]

The first one is almost certainly a Megger type of instrument, the crank handle is the giveaway.
Does the second one have a battery or the fittings for one ? can't see the diagram in the lid well but I would venture a whetstone bridge type of thing.
No type numbers you can google ?

[llondel]

I have an interesting box, acquired from my late FIL. It looks like some sort of crystal calibrator for the US military but putting the part number into Google gives no results. It comes with spare parts in neat little drawers, plus some crystals of various different frequencies. I'll see if I can dig it out

[G-CPTN]

There are people who collect, and pay good money for, all sorts of stuff.

Put it on Ebay and see what happens.

But don't you need some idea of what it is/does?

Maybe someone could identify it from the photographs (I know that's what you are trying to do here).

[Pontius Navigator]

G CPTN, plenty of stuff like that with totally wrong descriptions.

[ian16th]

I suggest that the 1st one is an Insulation Tester, with 250v and 500v outputs. The name Megger is the common UK name for such a device.

The Wee Megger.

The device in the lower picture might be an early Multi-Meter. A sort of precursor of the AVO meter. An in focus picture might help.

These things have a small collectors market. They have been superseded by modern kit. Last time I checked, my AVO Model 8 was worth about £50.00. Dunno if it has gone up or down since.

[Boac]

Thanks, all - especially Ian. As I said, both are German in origin. The previous owner of my house was an extremely talented engineer and I have only now got round to checking this lot. When we moved in we found an electrical distribution panel from a German Navy ship!

Oddly, over the years, I have found two wiring errors of his, despite I'm sure his being fastidious. Two sockets where neutral was switched and not live.

Anyway, here is an in-focus close up of the 'meter'.

[Wodrick]

Is it possible for a better photo of the wiring diagram in the lid of the second unit ? I've decided it's not a bridge but it is very low reading, maybe that's the point.

[emjay]

The 'Korrekter' scales suggest a relatively low AC voltage meter - indeed there is a bridge rectifier shown in the schematic.
The diodes available in that vintage of equipment were of less than ideal specification (and you get stuck with a forward voltage drop even with a modern Schottky diode).

This results in an under reading and significant low end "cramping" of the actual pointer deflection on the lowest range (3V AC). Since the effect is reasonably predictable, the correction scale takes the cramped reading and turns it back into an estimate of the true value.

However, though the correction scales start at zero volts, this is misleading - there will be a minimum AC voltage which is not enough to get the diodes into significant forward conduction to provide any reading at all. It was best to disregard readings less than 25% on the lowest AC scale. A quick check of a venerable AVO Mk II manual will give a similar caution.

[Boac]

Is it possible for a better photo of the wiring diagram in the lid of the second unit ? I've decided it's not a bridge but it is very low reading, maybe that's the point.

I will produce today, Wodrick.

Thanks to all for all the diagnosis and amazing knowledge demonstrated! The main question is do I just 'bin' both boxes or is there some use for them?

[ian16th]

Not really any use for them, as I said, modern kit has supperceded what you have found.
A collector might like to have it, or your local Tech College/Museum.
My AVO is only used on the rarest of occasions as my el-cheapo Chinese digital meter is sufficiently accurate and handier and simpler to use.
If I'd had my Chinese meter in 1962 when I had the Akrotiri Green Satin bench, it would have been good enough 90% of the time.

[emjay]

An alternative is a donation to a local Radio Amateur group and/or Makerspace. The existing form is pretty well obsolete but the actual meter movement is often very well built and can be repurposed with some custom circuitry. For some applications, you cannot beat a sensitive, lightly damped analogue pointer.

[Pontius Navigator]

emjay, agree, I had an analogue voltmeter for my car. Connect to the battery or cigarette lighter and hold it in place with the window. I think it was Gunson's or similar. Easy to check when driving rather than focusing on numbers.

Digressing more, remember how we used to plumb in extra instruments in our cars, oil, volts, amps, temps etc, now all reduced to warning light icons.

[Boac]

emjay - thanks for the nod on 'Makerspace'. I have been in touch with my 'local' and am waiting to hear back.

For Wod

Megger lid

Meter lid

[TheGreenGoblin]

Ach zu, so vas your ex house owner a Nazi spy, code named "Der Nadel?"

Either that or you have yet to find the rest of Dr Frankenstein's kit?

[Boac]

Nein, er heisst 'Der Hammer'.

[Wodrick]

I would give them a run on e-bay with a fair reserve so you don't have to give them away.
In my opinion you have a 250/500 volt AC/DC insulation tester and quite an old multimeter,
Volts and Amps 150vac/600vdc and up to 30 amps (up to 10 amps then 30amps with the external shunt)

If they don't go on e-bay then I agree museum or technical college may be interested.