How exactly works the soyuz first stage separation?

[kunok]

I understand how the upper connector disconnect but I don't know how the lower one does, and I'm unable to find. The best explanation I found is this http://www.russianspaceweb.com/soyuz_lv_stage1.html in the right side, but it doesn't really explain how they are "severed", probably the best explanation out there is in perfect russian

[kerbiloid]

https://translate.google.ru/translate?sl=ru&tl=en&js=y&prev=_t&hl=ru&ie=UTF-8&u=http%3A%2F%2Fkik-sssr.ru%2FIP_4_Turatam_old_Razdel_1.htm&edit-text=

[Nibb31]

Reading that article, the entire thrust of the boosters is translated to the core through four ball joints attached to a thrust structure at the top of the core. The separation works like this:

1) They reduce the thrust of the side boosters. The difference in thrust between the core and the boosters causes them to "lag behind" the central core. This disconnects the ball joint at the top of the boosters.

2) The disconnection triggers separation sensor. Which does two things:

• A valve at the top of each booster vents the upper oxygen tank which pushes the boosters away from the core.
• The lower connections, which contain power and data lines, are severed by pyro bolts.

Very interesting stuff.

Edited January 18, 2017 by Nibb31

[WinkAllKerb'']

i found this video pretty well made for general public the other days for the basic stuff, mid' in depth tech details, (was explaining reentry to someone using the end of the video)

Edited January 20, 2017 by WinkAllKerb''
(14:55 hum hum, well that very kerbalish xDr)

[magnemoe]

On 18.1.2017 at 0:20 PM, kerbiloid said:

https://translate.google.ru/translate?sl=ru&tl=en&js=y&prev=_t&hl=ru&ie=UTF-8&u=http%3A%2F%2Fkik-sssr.ru%2FIP_4_Turatam_old_Razdel_1.htm&edit-text=

Note the X shaped strut structure on the bottom of booster. This should be very recognizable for KSP players. 
Only weird thing is the dual strut where the other strut passes trough the eye. It might be to stabilize the struts during separation so they don't hit the core 

Also how they uses the oxygen as an cold gas truster on the top to separate. Because of the cone shape SRB seperatrons would be impractical. 

[kerbiloid]

9 minutes ago, magnemoe said:

Note the X shaped strut structure on the bottom of booster. This should be very recognizable for KSP players. 

That's what impressed me first.