Budgetary estimate to use for 5kV Transfer Switch

[jraef]

Has anyone bought a 5kV 200-400A (or so) ATS recently, as in the last year or so? I haven't bought one in over 10 years. I just need a rough order of magnitude (aka "hand grenade" price) to plug into a comparison on a project, nothing fancy, no spec. In fact my contention is that they don't need an ATS, all they need is two starters with a Kirk key interlock, because they are only going to transfer the loads twice per year, manually. It's going on the output of a VFD that they want to use on two different pumps, but one of the pumps only has to run twice per year for a few hours each time. End user wants to use an ATS, I think it's serous over kill.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[waross]

Are manual transfer switches available in an appropriate size?
Are you using draw-out starters?
The very simplest and cheapest interlock that I have ever seen was a coupling and a piece of 3/4" pipe.
The application was a set of 100 ton autogenous ore mills that were occasionally reversed to equalize wear.
The mills were started/controlled by 13 kV Magna-Blast draw-out breakers.
Each mill had two breaker cells with the connections reversed on one.
In the dividing wall between the cells there was a 1" sleeve or coupling welded in place with a piece of 3/4" pipe trapped inside.
To reverse, the breaker was racked down and withdrawn, the pipe was slid through the sleeve from one compartment to the other and the breaker was installed in the second, reverse connected cell.
I support your Kirk-Key interlock solution 100%.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[GroovyGuy]

Hi jraef,
I have never seen a 5kV "ATS", of course that does not mean that they don't exist. I would think that your would be required to use a couple of 5kV load-break switches, along with a couple of kirk-keys. This assumes that a manual switching is OK. Don't forget that you should interlock the two switches, such that only one witch can be closed at a time, plus a second set of interlocks to the disconnecting device on the input to the ASD. The second set is to prevent operation of either switch, unless the ASD is proven to be de-energized. Although the switches can handle the interruption of the motor current, it is likely that the ASD will not like this .

I think that your suggestion wrt using a couple of 5kV motor starters is quite sound, but perhaps not the most cost effective solution. I have done something similar a few times for synch transfer schemes on up to six (6) 7000hp 5kV ASDs. It works rather well.
GG

"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)