Permutation question with Kirk Key interlocks 1

[bdn2004]

We have a UPS system involving two panelboards that have a total of 6 circuit breakers. One system feeds the other.

What I am trying to figure out is all the different combinations that these switches could possibly be in, because I want to individually analyze each case for any backfeed or safety issues.

It's not as easy as it sounds. For example SW1 on all the rest off...case 1. SW2 on, all the rest off...case 2, SW1 and SW2 on, all the rest off..case 3, etc.

Does anyone know the mathematical formula for this, that is how many possible combinations there are? Reference? It would be even better if they fit into a matrix by positions, to make sure I've got them all.

 

[WhiteyWhitey]

I figure it to be 2^6.

 

[racobb]

Since you are talking about a UPS why not just consider the worst case load condition and forget about the sexy math problem. If you know the probable switch positions then use that, otherwise use worst case and move on.

Alan

Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep!
Ben Franklin

 

[dpc]

This does not seem like a good application for Kirk Key interlocks - if you can't figure it out, how is the poor guy on the swing shift going to figure it out just after waking up.

Without knowing more about your system, I'd suggest some main breakers.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[racobb]

bdn2004,
Realized that I mis-read you post originally...a one line would probably help.

Alan

Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep!
Ben Franklin

 

[EEJaime]

Whitey-Whitey is correct if you are looking for the quantity of 2-breaker combinations. If you are looking for all possible combinations I believe that number is "6-factorial" or "6!", which is 6x5x4x3x2x1=720. I think my memory serves me, but it's been a long time.

Good luck,
EEJaime

 

[stevenal]

Consider 2 two position devices.
off-off, on-off, off-on, and on-on are the four possible combinations.

2^2=4. Whitey is correct.

Or try converting binary 111111 to decimal and adding 1 for the all off zero case.