Luftwaffe NA8 utility power supply for 100 Watt Sender

[kriegsfunker]

Thank you Pierre - this is very very useful.

[val]

Pierre - from Germany - Werner?

Regarding Glimmlampe - it is connected directly to mains power without any current

limiting resistor i see on the schematics...so i wonder is there resistor integrated

inside glimmlampe.

[kriegsfunker]

The schematic is a simplified foundational schematic.   There are other components behind a metal shield with the glimmlampe,  I will record them and let you know what they are.

[kriegsfunker]

8 hours ago, tornfuté said:

The schematic is very simple  , one transformer for HT and one for LT

a bridge , filter  . Yuri you are right the big resistor in my SGL T 100 must be 

the equivalent of your resistor . In Na8  the owner tell me that the capacitors

must still be original . In notice  i get it’s not  said the value , nor if it’s paper

or electrolytics capacitors, but they are still working 

 

 

I have measured a 400 uF electrolytic cap in the NA8 and it reads about 180 uF.   I tried re-forming it, but that didn't change the reading.    I opened it up and it's the standard electrolytic/paper capacitors.   All need to be updated to modern ones (hidden inside).

 

[kriegsfunker]

Glimmlampe information:  The writing has seriously deteriorated with oxidation and age, but I could find some logo which is shaped like a circle with another circle inside.  There was writing there " 220V / 672"   That's all I could read from there.

[tornfuté]

About SGLT 100 i search for the 2nd unit , it's a little bit different Inside ,  some capacitors are dated 1954  i believe oïl capacitor  but 1 KV  seems me not enough

seleniums are square and not round . the glimmlampe is present  i can't unscrew it but it's  like a TE 5  small neon  lamp used  in NA6  i don't know if it's original

val  no it's not Werner

here pictures of this second unit  i get it years ago with a 100 ws i sold , it was annonced in working order , but i never try, it   looks like that  psu was restored

[kriegsfunker]

Removing the old capacitor material from inside of it.   As you can see, the capacitors don't look healthy, and there's lots of oxidation showing through the paper.   Hence the 1.6 uF reading for a 400 uF capacitor.

 

 

[val]

Nice job! Was it polarized capacitor?

[kriegsfunker]

yes

[val]

This shows nicely you just can't reform those old capacitors. Time does it's job.

Only solution - just replace.

[kriegsfunker]

A badly ruined capacitor has cracked its Bakelite container

 

 

[kriegsfunker]

On 11/01/2019 at 22:30, kriegsfunker said:

Glimmlampe information:  The writing has seriously deteriorated with oxidation and age, but I could find some logo which is shaped like a circle with another circle inside.  There was writing there " 220V / 672"   That's all I could read from there.

This may be the best substitute

 

https://www.buerklin.com/de/glimmlampe-mit-vorwiderstand/p/33g674

[kriegsfunker]

Look what I found 🙂

 

 

[tornfuté]

It’s what i get copies , but there is no valuable info inside , 

i make pictures of some bulbs i own 

[val]

Merci, @tornfuté !

[kriegsfunker]

It should have a schematic and other information:

 

 

[kriegsfunker]

Table of contents

[kriegsfunker]

Thanks Pierre - looks like mine is probably the one on the left - 6727 (220 V)

[kriegsfunker]

Front panel cover removed:

 

[kriegsfunker]

NA8 becoming empty.....

 

 

[kriegsfunker]

Restoring the high-voltage chokes.  Great to have the specs on the components:  0.45 wire diameter, 6225 windings.  3600 test voltage.   Model V.7340  Sp.V. 21962

 

[kriegsfunker]

Yep, this power supply was stored outside.....

 

 

[kriegsfunker]

Does anyone know if there are any effects of running an appliance that worked on German 50 Hz AC power, from an outlet with 60 Hz AC power? 

[kriegsfunker]

I forget what I even have.  I found a curious box today.....

[Funksammler]

8 hours ago, kriegsfunker said:

Does anyone know if there are any effects of running an appliance that worked on German 50 Hz AC power, from an outlet with 60 Hz AC power? 

Running a 50Hz transformer on 60Hz should not be a problem. The issue is the flux created in the core and the associated heat loss, the lower the frequency the higher the flux, if it reaches saturation you will start generating excess losses and heat which could destroy the transformer. So running a 50 Hz transformer on a higher frequency reduces the flux and will not cause problems. The filters designs were optimised for 50Hz, but since these are mainly low pass they will also be more effective at rejecting the higher mains frequency.

This is why aircraft installations often use 400 Hz power supplies and how modern switched power supplies get away with using tiny transformers, the higher frequencies generate less flux and allow the iron cores of the transformers to be much smaller....

regards,

Funksammler