Talk:Transfer switch

Why did Wtshymanski delete (almost) all the content on Selection of Transfer Switches for Home use?
I believe what Wtshymanski deleted was useful information for hundreds of potential readers. I wrote it after losing power for 5 days and going through the process of evaluating and selecting a transfer switch to work with a generator. If someone wants to remain ignorant they can just hire an electrician to buy and install one for them. However I'm an Electrical Engineer and wanted to learn about them myself. After I did, I thought it would be good to share what I'd learned. Where else could someone learn about this? I couldn't find any good source when I needed it.

The material wasn't a "Parts List" like Wtshymanski rants about on his/her page as not belonging. Wtshymanski, request that undo your deletions. (Forgive me in advance if I don't check this page again soon; I'm pretty busy with my regular full time job).

Here, here!Longinus876 (talk) 20:05, 30 October 2012 (UTC) Victorcache (talk) 18:22, 24 February 2011 (UTC)
 * That was a very short edit comment, I'm sorry. What I should have noted was that Wikipedia is not  a how-to guide. Specific recommendations and tips on the sizing, selection, and installation of a transfer switch are outside the scope of an encyclopedia article. You could put it in a Wiki book, instead.  --Wtshymanski (talk) 18:47, 24 February 2011 (UTC)

Three-way transfer switch
I have two (2) GENERATORS on my RV. How would I setup the transfer switch from one GENERATOR to another and also transfer to shore power.Electricly.

Skip Duld ( 21:45, 10 April 2007 172.164.65.247)

Use a three-way transfer switch. They are often designed for boats where they switch between generator, inverter (battery/solar) and shore power (example example2). Or you could use multiple transfer switches, one between the two generators and one between the other transfer switch and shore power. --203.28.150.120 (talk) 07:56, 16 April 2008 (UTC)

Large campuses
How do large campuses operate transfer switches, especially when there are non-critical loads that don't need transfer in each building? Do they use transfer switches in each building or separate electrical systems back to one transfer switch? Or do they have a separate generator and transfer switch for each building? Also can we have more detail in the article about transfer switches that do load shedding - I've seen some info on these but how do they integrate with the system? --203.28.150.120 (talk) 07:56, 16 April 2008 (UTC)

There is no general answer to this question- every design depends on the specific project requirements and parameters. A large campus within a single city-block is not comparable to one occupying a number of city blocks, where distribution may be done at high voltage.

In many cases, it is sensible from a reliability/redundancy standpoint to have 1 (or more) generator plant(s) that may or more generators operating in parallel - with the requisite redundancy. From a design standpoint - and in some jurisdictions also from a code standpoint - it is prudent and good enginering practice to divide the loads by category (such as life-safety and critical, for example) and possibly based on other further criteria such as location, importance, etc. to permit more granular control and switching. Generator power would be distributed throughout the building or small campus to the ATSs and the output of the ATS would then supply a distribution panel feeding the backed-up loads. The ATSs would typically have different time delays such that they transfer the load to the generator sequentially rather than all at once; the amount of power required to start an inductive load (which is likely a high percentage of loads in a large building/campus) is much greater (roughly 6x) than the power required to run the load. If the full load were to be connected to the generator in one shot, either 1) the generator would need to be MUCH larger than it would be if otherwise stepped, and then would run at a low percentage of capacity, with reduced efficiency and other concerns (such as carbon build-up in the engine, etc.) caused by under-loading the generator. Alternatively 2) the loads are applied sequentially with the larger loads applied first and then the smaller ones (where this is practical from a code standpoint).

Additionally, by having the loads separated by multiple ATSs, it is easier to handle the starting and potential failure of parallel generators. When the first generator reaches stable operation, one or more ATSs can transfer, loading the generator plant up to the available capacity. As additional generators become active and synchronized, they are connected to the common generator bus and then additional ATSs can transfer, to suit the additional capacity from the additional generators. If a generator fails, ATSs can be shut off simply to avoid over-loading the generator plant and causing a mass shutdown of the plant.

In a larger campus spanning multiple city blocks (such as a University) where the large distances require high voltage distribution, but the utilization voltage within the buildings is 480V in the US and 600V in Canada (Other locations use different voltages, such as 415V, etc.) - it may be more cost effictive to have distributed generation, where each building (or group of buildings) have their own generator(s) and operate at the utilization voltage, rather than have a common plant, as high voltage has significant equipment and labor costs which may reduce any benefits associated with a single shared plant. — Preceding unsigned comment added by 209.250.153.11 (talk) 23:28, 10 August 2011 (UTC)

Static Transfer Switches
We need to add a paragraph or two about how static transfer switches work as well... The Deviant (talk) 14:26, 27 May 2008 (UTC)

Hyperlinks Some of the concepts may not be familiar to some readersLonginus876 (talk) 20:02, 30 October 2012 (UTC)

Questions not answered
I came to this Wikipedia article to see if power to devices was lost momentarily when using a transfer switch. The article mentions soft transfer switches without giving this as a definition, since it mentions that this type of switch needs to synchronize the power from the other source and can ramp up/down from the other source. Is there a term for a transfer switch that does not momentarily lose power when switching? Or does it depend on the transfer switch? Is there something specific I would look for in the labeling of the transfer switch to know if power would be lost momentarily? I probably won't come back, but I wanted to let you know where I personally thought this article needs more information. Thank you. — Preceding unsigned comment added by 2601:182:C680:1450:38B8:61B8:7765:6DE (talk) 01:39, 18 June 2017 (UTC)
 * What parts of the discussion of "open transition" and "closed transition" were unclear? --Wtshymanski (talk) 17:22, 1 July 2017 (UTC)