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1882 Pearl Street Station 3-Wire

OttoEngineMan

New member
This is a piece of underground electric cable removed from the Edison Pearl Street Power Station of 1883. This was recently unearthed after the bombing of the WTC in NYC on Pearl Street.. To give you a example how big and massive this must have been to lay, a piece you see pictured of 1ft long weighs 15lbs and the three solid brass wires inside surrounded by black tar are over a 1/2inch in diameter. This was dug up by the bridges and harbors dept in NYC and I got it from a guy who works there and dug it up..Very very rare and early electrical history. I bought a 3ft piece from him and cut it into 3 one feet pieces and recently sold one to a museum in washington state called the spark museum..
 

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LCJudge

Subscriber
Edison believed DC was the way to go on electric service. It would require a multitude of power generating stations and much heavier service connections as witnessed by the large diameter wire. AC won out with its obvious advantages.
 

Junkologist

Subscriber
Very cool piece of history! Must have been very difficult to handle that stuff when it was installed.

I pulled some very old cable out of the ground in Cleveland, Ohio some years ago. It was about 3” in diameter, encased in lead with an outer rubber covering that looked like old fashioned radiator hose. Inside were three stranded copper conductors insulated with oily paper.
 

OttoEngineMan

New member
Is the exterior pipe or something else? How did they splice the copper rods together?
Outer material is heavy cast iron pipe with a black tar insulator inside. It was spliced together with large junction boxes. I do have a 1883 Scientific American Journal here somewhere depicting the working laying this conduit in NYC . I also have one of the huge 100LB cast iron junction boxes that was dug up along with the conduit.
 

OttoEngineMan

New member
Along with the section of cable, I also received one of the 3 wire junction boxes and a 2 wire junction box too. These are made of heavy cast iron all bolted together with large brass lugs and terminals inside. What you see on the outside is concrete and asphalt from street work. Somewhere I do have a 1883 edison catalog depicting these awesome early items forsake.
 

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Frank DeWitt

Subscriber
What a great thread. We all know Edison got AC vs DC wrong, but when you think of all the steps needed to get power from the station to a lamp in a home, he got an amazing number of things right.
 

Radiomike

Member
Three wire DC was a common method of power distribution, it gave two voltages V and 2V. The prolem arose with unbalanced loading between the two poles.

http://www.eeeguide.com/three-wire-dc-distribution-system/

For this reason balancer sets were used to keep the voltages about equal.

http://www.eeeguide.com/three-wire-dc-system-balancer-set/

DC was popular as it made speed control of motors easier. Many transit systems still use 750VDC as their supply. Although modern technology allows the use of AC motors. Earth return currents were a problem in early systems causing corrosion. Negative boosters were used to keep one pole of the DC at ground potential for traction.

Mike
 

Pete Spaco

New member
It never occurred to me that "tar" would be that good an insulator, considering that it's mostly carbon. I will have to go ohm some out one of these days.

I guess we've all read and heard a lot about Edison and DC. But in recent articles and documentaries about him, Tesla, and Edison's backers, I think he knew, later on, that AC was the right way to go. He just had too much personal capital at stake to give in. The guy was not dumb.

Pete Stanaitis
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Junkologist

Subscriber
It never occurred to me that "tar" would be that good an insulator, considering that it's mostly carbon. I will have to go ohm some out one of these days.
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Tar has been used as potting material for transformers for many, many years, but if the voltage is high enough, it can short through a carbon track. One case would be a neon sign transformer being abused as a power source for a Tesla coil. They’re output is typically 10,000+ volts.
 

OttoEngineMan

New member
The 2 wire system was only approx 1 SQmile around NYC from the Pearl Street Station. It is unreal how large a diameter that solid piece of copper is that was cut down the middle like a 1/2 moon. this is as early as it gets for electrical distribution in the entire world..
 
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