AVO Model 40 Variations.

I think there are the following variations for the AVO 40. Any extra information will be appreciated.


40 (MK1) Early aluminium case, horse shoe magnet battery cover with 2 probes
40 (MK1) Late aluminium case, modern magnet, battery cover with 3 probes
40 MK2 Marked MK2, aluminium case battery cover with 3 probes
40 MK2 Marked MK2 bakelite case battery cover with 3 probes
47A In wooden box
47S Marked with an "S"
48A Admiralty, wooden box with Multiplier 3600 Volts, shunt 120, shunt
480, transformer 60/240A

I wonder if exists an AVO 40 mk1 with baquelite case.

[pmmunro]

Up until the Second World War, all full-size Avometers had aluminium cases. As this became a premuim material, principally reserved for aircraft, it would have been in short supply for Avometers.

I have no way of verifying that this is why Bakelite cases were introduced but it does seem likely.

The most robust case of any Avometer is probably the cast aluminium case used on early Heavy Duty instruments, designed for the Great Western Railway but first supplied to the Western Region of British railways in 1948. For some reason, probably to reduce weight, later Heavy Duty meters had Bakelite cases which are nearly always damaged in surviving examples.

PMM

thanks for your answer!

[Sinewave]

I've got a GWR Avo, but it's in bakelite.

I found another AVO 40 variant (in black)

40 (MK1) Early, aluminium case, horse shoe magnet battery cover with 2 probes. (1939-194?)
40 (MK1) Late, aluminium case, modern magnet, battery cover with 3 probes. (1940-1952)
40 (MK2) Marked MK2 but with old style binding posts, aluminium case. (AFTER 1945?-1946?)
40 MK2 Marked MK2, aluminium case battery cover with 3 probes (1952-1986)
40 MK2 Marked MK2 bakelite case battery cover with 3 probes (1970?-1986)

47A In wooden box
47S Marked with an "S"
48A Admiralty, wooden box with Multiplier 3600 Volts, shunt 120, shunt
480, transformer 60/240A


Will appreciate opinions about dates and more possible variants or if anyone have more info about Avo 40 production

[Sinewave]

I've got some Model 40s and 7s like that, with the PF terminals and the first type of connections. They're nice for the collection.

I added the MK1 with baquelite case during the WW2



40 (MK1) Early, aluminium case, horse shoe magnet battery cover with 2 probes. (1939-194?)
40 (MK1) With baquelite case due to WW2
40 (MK1) Late, aluminium case, modern magnet, battery cover with 3 probes. (1940-1952)
40 (MK2) Marked MK2 but with old style binding posts, aluminium case. (AFTER 1945?-1946?)
40 (MK2) Marked MK2, aluminium case battery cover with 3 probes (1952-1986)
40 (MK2) Marked MK2 bakelite case battery cover with 3 probes (1970?-1986)

47A In wooden box
47S Marked with an "S"
48A Admiralty, wooden box with Multiplier 3600 Volts, shunt 120, shunt
480, transformer 60/240A

[avocollector]

Years ago I was going to try and collect every type of large Avometer I could find just for fun. I have about 40 or 50 (not sure as most are carefully stored away in sealed plastic boxes) ranging from Model 16 to Model 40. However I had no idea so many variants existed even of a single model and many thanks to Aito and others for posting this information. Have been forced to throw in the collecting towel as a) no more room b) no more room c) see a and b - but this really shows the huge variety of what I in my ignorance thought was a simple quest.

[The Philpott]

It's astonishing how many variants were produced, the company bent over backwards to accommodate the requirements of customers- probably to their own disadvantage in some respects- efficiency and cost-effectiveness must surely start to suffer. (From what i am told this is what compromised Riley Coventry in the pre-war years- too many variants for their own good.)

The early archives are sketchy to the extent that it might still be feasible to find a variant that is effectively unknown. That would tempt me, but having 10 in full working order (and 16 avominors likewise) i would lose track (and run out of room) if there were any more.

Dave

Hello, i am looking for some photos of the wooden box that goes with the AVO 47. I will appreciate them.

By the way, speaking about photos, The Philpott, remember if you have time one day to show the photo of the guard/helmet in the Precision Avometer.


Thanks!