Tores mailbox VIIC and VIIC/41 operation and technical details

[Raymic1]

Cant wait!!! Thanks Don, Tore et all.......

[Katuna]

Tore - Care to have a go at a translation of this Battery Switch data plate? Google can't figure it out. I think it has something to do with foreign voltage but I can't decipher it.


Thanks!

[Don Prince]

Hello Katuna,


My best guess:


When charging the battery in series from an external circuit where + pole Port and - pole Starboard on the main switchboard (together) design/connection.


Battery main-switch 1


Regards,
Don_

[tore]

Katuna.
As you probably know the two battery groups are separated in two compartments no 1 battery right in front of the engineroom and no2 fore of the controlroom. These two battery groups can be coupled to the main switchboard by the automatic circuitbreaker ( overload current 5000 amps. in 6 seconds ) where the batteri groups can be switched either in series or parallel depending upon the voltage required. In case of charging the batteries in serie from another source but your own, like a shore installation and /or ship you switch your own batteries as the this warningplate says. I guess Dons translation is not bad and my native tongue is not German, but I guess the text reads word by word : In case of charging the batteries in serie from a strange current circuit you should switch together the plus pole port and minus pole stb at the main switchboard.
On the plate below: As Don says
Battery main switch 1

Tore

[Don Prince]

Hello Mr. Tore and Katuna,


That last post makes a lot of sense now...  The batteries in parallel would allow a high current charge to happen while the U-Boat was in port. When out at sea and high current charge of 1660 amps with the battery in parallel (E-motor Armatures always parallel when charging) and driven by a Diesel engine at high speed with the prop un-clutched. Then at 830/415 amps, the battery in serial and driven by a Diesel at the appropriate lower speeds.

My internet translator and my German - English Dictionary just ain't as good at Mr. Tore's experience...

Regards,
Don_

[Don Prince]

Hello Mr. Tore,


Overload current of 5000 amps for 6 seconds - It looks like the only thing that could cause that much current would an e-motor or a switchboard short. I would think that if any of the electric motors for the pumps would catch fire and burn up and not cause that circuit to disconnect? Also, I believe that the pumps and motors wiring goes to internal power panels which are fused? Have you ever seen these breakers pop open?


Regards,
Don_


 

[Katuna]

Yikes! Six seconds is an eternity at a dead short or locked rotor amps. That'll get those windings glowing.


I don't recall if I've asked before but, does anyone have any photos or drawings of the Automatic Battery Switch? Even a schematic would be great. Other than a photo of the cabinet door I can't find anything. I could probably come up with a reasonable looking bit of switchgear but it would sure be nice to have a rough idea what it looked like. Did you ever see inside there Tore?

[Katuna]

Almost forgot, thanks Tore and Don. That translation makes much more sense than what I was getting. I think my Google Translate started the weekend a little early.

[Don Prince]

Hello Katuna,


Pages 406 and 407 in Skizzenbuch; I explain how it all works. The automatic battery switch does not look to be complicated. I have attached the rotary schematic.


Regards,
Don_

[tore]

Don
Very good I was just looking through my files and realised my drawings were of such quality not worth posting. Anyhow I am posting a bad copy of battery switch no1 situated just opposite the galley. We very seldom had trouble with the switch, as Don says it is fairly simple. 5000amps for 6 sec. seems to be a lot, but the switch is for protection of the battery, the triggerpoint for a massive shortcircuit is 13000 amps. Other electric components had local protection by fuses connected to the starters.

[Don Prince]

Hello Mr. Tore,


I spent the last 3 days studying the welding machine schematic on Page 415... I believe I discovered the keys to the kingdom and now I think that I understand how it works. I have uploaded the latest version of Skizzenbuch into Dropbox. Would you please take a look at page 415 and let me know what you think?


Did you ever use the port e-motor as a welding machine on U-995 or U-926 as the EO?


Regards,
Don_

[tore]

Don.
Sorry we never used the port E-motor as a welding machine on any of our VIICs.
Tore

[Katuna]

Thanks for the battery info guys. I you stumble across any photos or drawings please post them. I've tried looking for relays and mag starters from that time period but have come up empty. I've worked with a lot of older electrical equipment (not that old though) so I have a good idea of what the layout of components would be but any additional info would be great.


Tore - Do you know if the components were mounted on a rack of some type or were the mounted to a plate at the back of the cabinet? I guess it doesn't make much difference if no one knows what it looks like in there anyway but, right is right.

[tore]

Katuna.
The components were usually mounted on a rack.
Tore

[Don Prince]

Katuna,


I previously posted the switchboard schematic to drive the E-motors... Here is the layout from u-historia.com and a Skizzenbuch photo.


Regards,
Don_