2phase 4wire

Status
Not open for further replies.
drcampbell said:
I didn't know 2P4W was still in use. I would enjoy knowing more. For example, how is the incoming service configured? 2 x 120/240 volts? What voltage(s) are supplied to large industrial buildings? How many transformers on a pole? How is power generated, transmitted & distributed? How are substations configured? Can you send pictures?
Click to expand...

Here are some historical photos to give you a sense of scale:
https://www.atlasobscura.com/articles/magnificent-photos-of-power-stations-in-the-early-1900s

Here is some detailed history of how the early power companies started then merged in Philadelphia:
http://citeseerx.ist.psu.edu/viewdo...32C94B4?doi=10.1.1.692.8508&rep=rep1&type=pdf
Original Schuylkill or Christian Street Station completed (known
as Station A, later A-l, within P.E. system). Designed by
architect John Windrim and Engineer William C. L. Eglin, plant
generates 6-kilovolt, 2-phase alternating current and forms
anchor of burgeoning Philadelphia Electric system.
Click to expand...
By the end of WW1 and the beginning of the depression they were generating in 3 phase, new transmission voltages were 3 phase. Old small plants closed and became substations, but still distributed two phase.

Early on they were using two phase @ 25Hz to back-feed DC converters in areas's that used Edison 120/240 DC.
That 25Hz system is still used for some of the electric rail, I believe.
This article talks about it:
https://en.wikipedia.org/wiki/Amtrak's_25_Hz_traction_power_system
 
I couldn’t get to the main incoming service only limited personnel had keys to get me anywhere during this holiday weekend. I did get a quick pic of the effected disconnect. True 2 phase 4 wire no neutral in this disconnect. Obviously no ground either. Mechanical only and with the water damage that is gone as well.
Of course I’m having trouble uploading the pictures off my phone I’m getting an error message.
Tomorrow is another day will try again to upload these. I will be back next week try and get some good pictures of the main incoming and the switch gear if possible. Anyone have a lead on a 4 pole 100amp fusible disconnect ? SqD don’t have one, don’t make one according to my supply house guy. I couldn’t find one online either.
 
Smash said:
I couldn’t get to the main incoming service only limited personnel had keys to get me anywhere during this holiday weekend. I did get a quick pic of the effected disconnect. True 2 phase 4 wire no neutral in this disconnect. Obviously no ground either. Mechanical only and with the water damage that is gone as well.
Of course I’m having trouble uploading the pictures off my phone I’m getting an error message.
Tomorrow is another day will try again to upload these. I will be back next week try and get some good pictures of the main incoming and the switch gear if possible. Anyone have a lead on a 4 pole 100amp fusible disconnect ? SqD don’t have one, don’t make one according to my supply house guy. I couldn’t find one online either.
Click to expand...


Siemens was mentioned earlier in this thread, did you try them?
 
Smash said:
Anyone have a lead on a 4 pole 100amp fusible disconnect ? SqD don’t have one, don’t make one according to my supply house guy. I couldn’t find one online either.
Click to expand...
https://www.schneider-electric.us/en/product/H463AWK/switch-fusible-hd-600v-100a-4p-nema12/

Can you fuse down a 200a switch?

NEMA 1, 240v: https://www.platt.com/platt-electri...-Pole/Eaton/DH424FGK/product.aspx?zpid=518699

NEMA12, 600v: https://www.platt.com/platt-electri...3-Pole/Eaton/DH464FDK/product.aspx?zpid=80771
 
 
Last edited:
zbang said:
Kind of late to the party, but I think 2-phase comes up here about every 9-12 months. Mostly in Center City, but IIRC there are still a few islands of it elsewhere (Hartford CT?, Niagara Falls?),
Click to expand...
Niagara Falls upgraded to 3 phase a while back. That leaves two Philly and Hartford. All the two phase here in Philly is all in old parts of Center city. Now the surrounding infrastructure is crumbling on a lot of these old buildings. That’s where I find myself there are major water problems throughout the massive cave of a basement. They keep adding sump pumps instead of trying to stop the water which tells me it cannot be stopped. Unless sidewalks are ripped up which then invites the city to the party and everything comes to a screeching halt. The people working in this building are doing real good work with the city’s youth I would hate to see them not be able to continue. I will do what I can to keep there lights on. I’m thinking of constructing a unistrut wall about a foot from this crumbling wall water proof the back and possibly give it a little pent roof and salvage the old switchgear that my disconnect is attached to. I will inspect the condition next trip. Thx for the links on the disconnects. Will dig in on them tomorrow.
 
Status
Not open for further replies.
Top