What type of railroad three phase delta with only two conductors did I observe?

[mdlueck]

Greetings,

This forum has been of significant benefit already sorting out one type of pole mounted transformer I observed. Here goes with another....

Railroad signaling and powered switch utility feed. The meter says per a utility label: "Three Phase Three Wire Delta". However, I only see two wires feeding the meter! (Single phase triplex.)

And one of the wires is bonded to ground.

The transformer mounted to the board has the following label. I figure that transformer is performing 240v / 120v/240v... basically adding the center tap ground that is missing with the Delta primary. Correct?

The utility pole transformer has insulated wires connected to both sides, nothing to the center tap.... and the bare ground is connected to the same bushing as one of the two insulated wires in the triplex! So that bushing gets pulled to ground, the other rises to 240v to 250v?

So the utility's "Delta Primary Service" is a single hot leg at around 240v to 250v? How exactly is "one hot leg" constitute a "Delta service"?

I know full delta, I know open delta, but this.... is a stretch to understand. Please again kindly do so.

I am thankful,
Michael Lueck

 

[LarryFine]

It looks like 240v 1ph to me.

 

[jim dungar]

You have a single phase service.
Could be an old meter.

 

[mdlueck]

Judging from the pole transformer connection, do you think I am concluding correctly that the one insulated conductor that also has the ground connected to the same bushing is truly ground, and thus the other insulated conductor has the full 240v?

I am thankful,
Michael Lueck

 

[LarryFine]

Yes, but definitely not sure enough to proceed without measuring it for yourself.

I'd want to see inside the disconnects anyway.

 

[mdlueck]

Yes, but definitely not sure enough to proceed without measuring it for yourself.

I'd want to see inside the disconnects anyway.

That, my friend, will never happen. That railroad crossing is right next to a county park....

"Historic Bridge Park of Calhoun County, Michigan - Visitor's Guide"

Historic Bridge Park of Calhoun County, Michigan - Visitor's Guide

A concrete bridge goes under the Michigan Central track between Chicago and Detroit, then I walk back the surface country road, pass the signal and powered switch at the East approach to the Battle Creek yard... which this configuration is powering that. Then pick up a park trail (not listed on the map) which leads to the #6 bridge.

Park suits me fine.... I am interested in both railroads and old bridges.

I did just get back from catching the last Amtrak for the day going through the Kalamazoo station. I checked a couple of the services powering railroad signal boxes here... yes, proper three phase delta powered by three tub transformers.... simple configuration.

Anyway, driving in the entrance of the bridge park, the drive pulls under this beauty bridge... the #6 bridge per the map with the bridges numbered.

I am thankful,
Michael Lueck

 

[CoolWill]

It certainly looks like straight 240 with one leg grounded, like a European system. For some reason they wanted a line to ground voltage of 240.