Design

I came up with a design for a c.1920 Utility Pole transformer. This version is bracket mounted. The design is completely taken from old photos. While only some of the transformers were ribbed as in this design I thought that the ribs gave the transformer an ‘old timey’ look.

  1. Case ribbed with four bracket mounting tabs. There are three connectors for the wires running to the structure .. hot/neutral/hot, with a neutral connector below. There is another neutral connector on the side. The bottom of the case has a drain plug. Back “In the day” oil would be drained here.
  2. The lid has an oil fill plug centered on the lid with holes to mount the high-voltage bushings.
  3. There are two high-voltage bushings supplied. If the transformer is three-phase both bushings would be used. If single-phase only one bushing would be used.
  4. .022” pins slide into the bushings and are fixed in place with super glue. I slid a bit out the top of the bushing leaving a longer length to stick out of the bottom of the bushing.
  5. The bushing/pin assembly is then glued into the lid .. using two or a single bushing depending of whether the transformer is single or three-phase.

Assembly

Assembled as a three-phase transformer. The high-voltage bushings can be bakelite (black or brown), Ceramic (white, tinted green or other color) or glass (translucent green etc.)

The case color can of course be whatever you wish based on any research and your preferences. I used a white primer as I wanted it weathered well.

Printed

Some attention needs to be taken where the supports attach. These will be mostly under the mounting tabs.

The lid has multiple supports for printing .. just ensure that the lid fits nicely on the case. The bushing holes are parallel to the mounting tabs on the case.

The bushings were removed from the supports .. check to ensure supports are removed from the base. A quick swipe of an emery board will do that .. if necessary.

The bushing wire supplied was made from a .022” pin. How far it extends past the top of the bushing is up to you. I just made it enough to glue a wire to. The bottom only has to be long enough to pass through the bushing holes in the lid. I suggest using super glue to do this.

Mounted

Two of the transformers mounted as three-phase. Wiring still needs to be done.

The weathering may seem a bit “Over the top” but I have a photograph of a transformer close to my own home with a similar level of rusting. That of course is up to you.

Secondary Distribution Systems
Residential secondary systems are predominantly single-phase, but commercial and industrial systems generally use three-phase power.”

The above is taken from my article on the Secondary Distribution System. This goes into enough detail for you to determine what voltage levels you need .. giving you the proper selection for a transformer for your needs.

Electric Power Distribution System

There are links at the bottom of the page to other articles showing how to wire both single-phase and three-phase transformers.

Mounted

Here the packaged transformer. It contains the transformer case, lid, two bushings, two wires and an instruction sheet.

The instruction sheet basically says everything I have in this article along with the link as above for the Distribution System with as it states links to wiring for single-phase and three-phase transformers.