Yet another Junk Box (10)

 I bought the contents of this junk box from a chap who was going to dump the lot, but as he also had an early Philips power supply I paid him a nominal sum for them about equal to the postage. I've not seen such battered stuff but many of the items are slightly unusual. I suspect some have been removed from domestic radios dating from around 1932 and others bought for home construction, some a lot earlier and some up to 1947. In total there are around 80 items including about 15 early valves, a few of which are quite exotic.

 The first items I've photographed are early condensers

2uF 500VAC made by the Hydraworks in Berlin which boasts "The Zenith of Quality" and clearly aimed at the UK market.

Interesting is that Hydra logo seen below in a 1951 document..

After nearly 90 years the condenser's value has significantly appreciated, as it now measures 6.66uF @ 0.28 ohms.

   Left, the Hydrawerk, Berlin factory as it looked in 2008 and an interior view before being converted into luxury flats. Reminiscent of the fate of the Plessey factory in Liverpool where I worked for over 20 years. Below the front page of a Hydrawerk document .

Below is a Type B6A block condenser made by Ekco having four separate values in the case. The four terminals on the far side are each marked "E" and the others 2, 2, 1 and 1. These now measure 2.14uF @ 0.42 ohms, 2.34uF @ 0.11 ohms, 1.06uF @ 0 ohms and 1.0uF @ 0 ohms. Well done Ekco, pretty impressive!


This is an anonymous block which appears to have five separate condensers within the case, however I didn't find any sensible reading across any pairs of terminals.


Two similar block condensers made by the same company as the one above. The one on the left carries the date 7th Oct 1932 and that on the right carries the date 31st Oct 1932 and neither has any measurable no capacitance between any terminals.


On the left a metal-cased Cossor Type T32 carrying two linked 1uF condensers and on the right a moulded bakelite 2 uF TCC condenser with its patent number indicating 1925.

The Cossor measures 1.36uF @ 0.02 ohms and 1.49uF @ 0.02 ohms and the TCC 4.12uF @ 3.4 ohms.


Below is a slightly later Type 65 TCC condenser marked 1uF at 250VDC measuring 1.13uF @ 0 ohms.


 Now, some transformers. The most common types were used to couple together audio amplifying stages, especially in early "straight" receivers which generally pre-dated the superhet. These transformers used lots of very fine wire wound on an iron core to provide a step-up ratio. Because of the very thin wire many junk box transformers from the 1920s and early 1930s have an open circuit winding from misuse.

Below is a very battered, but otherwise sound, metal-cased Cossor transformer from around 1929. The primary measures 1.3Kohms and secondary 4Kohms. The cover on the underside is marked "Ratio 3:1" although, being pedantic it should say "Ratio 1:3".


This interstage transformer is marked "Ferranti" and was made at its Hollinwood Works where they made transformers weighing as much as a hundred tons. As is very common the grid winding is open circuit.


 Here's what looks like an early mains transformer. Difficult to date but could be from 1928 to 1937. It's fairly heavy and the laminations are 80mm x 80mm.

The primary winding measures 15.4 ohms and the secondary (one side of which is connected to the frame) 12 ohms which seems a bit odd. Perhaps it's an isolation transformer?

more to follow...

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