The Siren Board

holler wrote: Also it is possible to have three phase power with just one transformer. They aren't very common but they are out there. You can spot them easy since they usually have three insulators on top of the tank.

There are lots of them in and around Philadelphia, usually delta secondaries, sometimes with a center tap.

Chris

landmobile wrote:

holler wrote: Also it is possible to have three phase power with just one transformer. They aren't very common but they are out there. You can spot them easy since they usually have three insulators on top of the tank.

There are lots of them in and around Philadelphia, usually delta secondaries, sometimes with a center tap.

Chris

Here is the siren on google maps if this helps.
https://www.google.com/maps/preview#!q= ... 6714&fid=5

Do they make 3 phase transformer? I got to say I never seen that set up before, two and one transformers.. Is some thing just in "South"?

By the look of street view it looks to be either wye or delta.

EWS Rules wrote:Do they make 3 phase transformer? I got to say I never seen that set up before, two and one transformers.. Is some thing just in "South"?

Yes they make the "all in one" three phase transformers:

http://www.ppiway.com/sites/default/fil ... _sheet.pdf

A lot of utilities don't use them since they can get everything done with single phase transformers.

The two pot banks are very common. Next time your out driving look at the transformers on three phase drops.

holler wrote:

EWS Rules wrote:Do they make 3 phase transformer? I got to say I never seen that set up before, two and one transformers.. Is some thing just in "South"?

Yes they make the "all in one" three phase transformers:

http://www.ppiway.com/sites/default/fil ... _sheet.pdf

A lot of utilities don't use them since they can get everything done with single phase transformers.

The two pot banks are very common. Next time your out driving look at the transformers on three phase drops.

Most I worked on are underground drops.. But I sure start looking.....

Do 3-phase sirens have longer "wind-up" than single-phase sirens?

Nope, it's the other way around. Single phase sirens usually have longer windups (unless the 3 phase is running on 208V).

Here is a Model 5A (3 phase)
https://www.youtube.com/watch?v=9tUihUbfe3k

Here is a Model 5B (Single phase) (not my video)
https://www.youtube.com/watch?v=TAjb0HtXU7Y

Unless it's a capacitor start motor. Those thing REALLY go when they are working right: http://youtu.be/D9WJDJdD5YI?t=49s

I'd rather bump this topic than start a new one, but I'm still confused on a few phase things.

1. This one is more of a clarification, but a 3 phase siren can run off 1, 2, or 3 transformers, given that they are able to produce power, right? And are pretty much all single phase siren setups run off of 1 transformer?

2. In terms of wires going into the siren, how many are needed to provide power for a 3 phase siren and a single phase siren?

3. Since my area is filled with Tempests, are T-128 and T-135s offered in both single and 3 phase varieties or they all 3 phase? Same question with 2001s as well. The ones around are seen with both one transformer and 2 transformers. Also, I believe all P-50s are 3 phase as well, am I right?

4. I thought that in order to have 480V, you would need 3 transformers, however, I'm seeing this P-50 run off of 2 transformers, yet have a very fast windup. What am I missing here?