The Story of Edison Dynamo No. 16
On 10 May 2011, members and officers of IEEE, officials of the Consolidated Edison Company of New York (Con Edison), and friends gathered at the Con Edison Learning Center in Long Island City, New York (see Figure 1), in the shadow of the Queensboro Bridge, to dedicate an IEEE Milestone plaque. The celebration and luncheon recognized the historical significance of Thomas Edison’s first central generating plant, which began operating at 257 Pearl Street, Manhattan, in 1882 (see Figure 2).
IEEE Milestone Dedication
After welcoming speeches by Ronald Bozgo, Con Edison’s vice president, central engineering, and Melvin Olken, IEEE New York Section historian and nominator of the Pearl Street IEEE Milestone, the keynote address covering the early history of the Edison system was delivered by Paul Israel, noted author, Edison scholar, and director and editor of the Thomas A. Edison Papers at Rutgers University (see Figure 3).
Moshe Kam, 2011 IEEE president, spoke about IEEE Milestones in general and the importance of the Pearl Street Milestone and then invited Kevin Burke, president, chairman, and CEO of Con Edison to the podium to help unveil the Pearl Street IEEE Milestone bronze plaque. A standing ovation followed (see Figures 4 and 5).
IEEE Milestone plaques are usually affixed to buildings or locations directly related to the achievement honored. In the case of the original Pearl Street plant, after a devastating fire in 1890, the building was stabilized and temporary generators were installed. The first generation equipment in the station was quickly outdated, and the buildings at Pearl Street were closed and razed before the dawn of the 20th century.
President Burke accepted the plaque on behalf of Con Edison and thanked all attending for this distinct honor. As the 257 Pearl Street site today is nothing but an open parking lot, the decision was made to install the IEEE Milestone plaque in the lobby of the Edison Building at 4 Irving Place, Manhattan, near a bronze bust of Thomas Edison.
Burke then spoke about a little-known Edison power plant, Pearl Street in Brooklyn (yes, there were two Pearl Streets!). He informed the gathering that thanks to the rescue and restoration efforts of Robert W. Lobenstein (the author of this article), retired general superintendent of power operations for the New York City Transit (NYCT) subway system, and volunteers from the Metropolitan Transportation Authority (MTA) Pitkin Yard Electrical Motor Rewind and Fabrication Shop (Pitkin Yard), a piece of early Edison history was saved. A bipolar Edison-Hopkinson dynamo bearing number 16 on its builder’s plate and rated at 100 kW, identical to the dynamos installed at the Manhattan Pearl Street station just a few days after the 1890 fire, is now proudly on display on the main floor of the Con Edison Learning Center (see Figure 6).
Burke presented a certificate of appreciation to the author for the intricate, historically accurate restoration of dynamo no. 16 (see Figure 7). He further invited all to go downstairs to the main floor after the ceremony to view and appreciate the fine work that was done in the restoration.
In his remarks, Lobenstein dedicated the restored dynamo to all engineers and electrical workers, past and present, and made a special dedication to the children as they will take up our mantle and become the backbone of the electrical industry in the future (see Figure 8).
After closing remarks by Ronald Bozgo, the dedication event adjourned for picture taking and a walk downstairs to see dynamo no. 16 on display in its new home.
Watching Over History
For over 38 years I’ve watched them, sitting quietly on the gutted turbine floor of the old 1905 Kent Avenue powerhouse (see Figure 9).
When the sale of our New York City subway powerhouses to Con Edison took place in 1959, the vintage 25-Hz generating equipment was gradually retired and ultimately removed from our old BMT (Brooklyn Manhattan Transit) 1905 Kent Avenue powerhouse. Until its closure in 1999, old Kent Avenue remained a switch house sending 11-kV power, generated at the remaining plants at 59th Street and 74th Street, Manhattan, to various transit substations in Brooklyn and Queens. Sometime during the 1960s, Con Edison began to store old equipment on the empty turbine floor. Two of about a dozen pieces were Thomas Edison’s early bipolar “long-waisted Mary Ann” dynamos. A small unit of approximately 30 kW and a much larger one of 100 kW sat side by side in silence, barely protected with rotting tarpaulins.
I became interested in these machines in the early 1970s when our substation crews were dispatched to the powerhouse to witness hi-pot testing of our almost century-old 11-kV feeders. Each time I walked through the plant, I’d stop by and marvel at the construction of these machines. I took several photographs with a Polaroid camera and later took some 35-mm photos. The large dynamo caught my eye because affixed to it was a plate that stated that this unit was one of the Brooklyn Pearl Street dynamos, identical to the ones installed at Edison’s Manhattan Pearl Street station after the destructive fire in 1890. Old dynamo no. 16 had a great lineage, though I puzzled: “Edison had a Brooklyn Pearl Street too?”
In the latter part of the 1880s, the Edison Electric Illuminating Company (EEICo.) branched out into Brooklyn. The First District powerhouse, ironically, was located on Pearl and Adams Streets in downtown Brooklyn, near the Brooklyn and Manhattan Bridges (see Figures 10 and 11).
EEICo. Brooklyn was a holding of Kings County Electric Light and Power Company (KCEL&PCo.), which became a Brady/Murray holding and was reorganized as Brooklyn Edison Company (BECo.) in 1919. BECo. did not become part of the Consolidated group until 1943, at which time it was acquired by Con Edison.
Here, the newer, more efficient technology of Edison-Hopkinson bipolar dynamos replaced the “Jumbo” design dynamos originally installed across the river at the Pearl Street, Manhattan, station in 1882. Brooklyn is where dynamo no. 16 went into service, together with other similar machines, powering nearby Brooklyn neighborhoods until alternating current (ac) systems superseded direct current (dc) generation, transmission, and distribution.
Brooklyn Pearl Street was the site of an interesting peak load dc to ac power conversion. It was initiated in the summer of 1897 and probably continued until about 1900 during each summer of the Coney Island resort season. This conversion used dc dynamos (most probably including no. 16) to power an inverted rotary converter to produce ac power. Transformers stepped up the output to permit a 12-mi (19.3-km) transmission of power to Coney Island where the voltage was stepped down and converted back to dc.
This dc power was not intended to meet local needs but rather to power the amusement parks and especially the resort hotels, which constituted a substantial summer electric load. Many owners were eager to scrap or sell their isolated stations that proved to be an economic burden since they remained idle during the off season.
During the 1976 U.S. Bicentennial celebration, the New York Transit Museum, located in Brooklyn Heights, was established. By then, I had begun my efforts to squirrel away vintage power equipment for display. I also worked over the decades with our museum to give talks and tours of our old turn of the 20th century substations.
I was always interested in power history and believed that these two early Edison dynamos stored at the Kent Avenue powerhouse should be preserved for future generations to appreciate. However, at that time I didn’t know that I would be doing the saving and restoring! I made it a point in the early 1980s to affix tags with my name and phone number to the dynamos just in the remote chance that, when the time came, I would be the one to give these historic machines a new more dignified home.
As time went on, I progressed up the ladder to my position of general superintendent in transit power operations. The time had come to retire the 25-Hz feeder systems from Con Edison. I was on hand on 3 August 1999 and had the privilege of cutting out the last 11-kV, 25-Hz feeder and retiring the old Kent Avenue facility from transit service.
I immediately began making inquires about those old dynamos. As they were considered scrap (what a shame), I asked if I could take the smaller unit and hoped that Con Edison would remove and preserve the large Pearl Street dynamo. We were about to take the smaller machine but discovered all power feeds to the old station crane were cut, and the only way to safely get it out was during building demolition. Even dismantled, the solid cast iron pieces were much too heavy to move by hand. I was disappointed, but I didn’t forget these machines or give up on my quest.
Fast forward to 2008 when developers were eager to get the land where the old Kent Avenue powerhouse stood. I received a call from the Con Edison demolition team. They saw the tags I had placed on those dynamos decades earlier and offered me both machines.
Heavy equipment was brought in and the building walls, one by one, came tumbling down. As crews tore through the south facing wall of the turbine floor, payloaders were brought in and both dynamos and a small 25-kW rotary converter that was discovered alongside dynamo no. 16 were saved for future historical research and restoration. I was working with Gordon Lockhammer and Joe Country, two fine gentlemen from Con Edison who arranged pickup of the small dynamo and the rotary converter. The 100-kW Pearl Street machine remained on site at that time in the rear yard, its fate uncertain (see Figure 12).
I brought the two smaller machines to our Pitkin Yard shop where I began the slow process of documenting, photographing, and restoring the small 30-kW dynamo.
After approaching friends in Con Edison, IEEE, and other historians, it was decided that the 100-kW Brooklyn Pearl Street dynamo would be given to me. Our MTA crane truck couldn’t lift the machine, so Con Edison, using heavy equipment, loaded it up and delivered this historic machine to Pitkin Yard (see Figures 13–16).
Restoring and Preserving History
One thing that must be understood is that Thomas Edison knew little of eddy currents. All of his early dynamos were constructed of solid and heavy cast or wrought iron from the upper yoke to the base. While it was claimed that an over 90% efficiency rating was obtained, that level of efficiency was reached at the price of heat. That is why, after the opening of the original Pearl Street station in Manhattan, large blowers were required to cool the fields and armatures in an effort to prevent burnout.
Everything that I learned in the reconstruction of the smaller unit was applied to the 100-kW dynamo no. 16. Dismantling the small 30-kW dynamo was accomplished using our five-ton (4.54-metric ton) shop crane. The two massive bolts holding the yoke in place were removed. The bolts were stamped “Edison Machine Works,” no doubt constructed at Edison’s New York Goerck Street works. The yoke was moved to a workbench where the field connection plate and all bolts were removed. A thorough cleaning and painting was the easiest part of the restoration. All nuts and bolts were sand blasted and chased with a taps and dies for easier assembly.
Utilizing the knowledge that I gained in restoring the small 30-kW dynamo, the next task was to dismantle the 100-kW dynamo no. 16 (see Figures 17 and 18). Almost every early dynamo had a plate on top holding a carbon filament lamp to indicate machine output. Outlines of such plates were discovered on the yokes. Replicas were fabricated at the shop using gray insulating fiberglass, looking much like the original marble connection plates. Brass sockets from the turn of the 20th century were affixed. I have several century-old glass-tipped carbon filament bulbs in storage, and one of these was installed on each of the completed machines.
The bearing caps were removed to reveal perfectly preserved babbit bearings and oil rings. The two outer rings pick up oil and direct it to the bearing surface, and the circular brass bearing mount perfectly centers both sides of the bearing on the armature shaft (see Figure 19).
With a little cleaning of the bearings, the armature was free to turn. We used to use what was called “dynamo oil” in our large subway generators and rotary converters, but after we ceased rotary operations in 1999, there was none to be had. A substitute of 30-weight motor oil will suffice for the time being. Figure 20 shows an antique dynamo oil can that I donated to the New York Transit Museum.
During the decades in storage at the Kent Avenue facility, thieves broke in and tried stealing anything of value such as copper builder’s plates, lugs, and bus work. Dynamo no. 16 even had its brush boxes stolen. The leads to the bipolar field wiring were found cut also. Working carefully, each cut end of the old field was spliced into new number nine motor wire. The splices were carefully insulated and imbedded back into the windings, while the new leads were directed outward to the yoke above. Each was checked for continuity and grounds and, to my surprise, after almost 130 years, the original coils were clear of short circuits and grounds.
The early dynamos, after assembly, had their vertical field poles wrapped with a protective rope winding. The 100-kW dynamo no. 16 still had its severely deteriorated wrapping, so a sample was taken and matched. Three 600-ft (183-m) spools of 0.250-in (6.4-mm) manila rope were purchased, and several days of careful wrapping ensued. The final outcome was impressive, as these dynamos seemed to take on a new life of their own (see Figure 21).
While field wrapping was underway, copper leaf brushes were made to replace the carbon brushes found retrofitted in the brush holders of the smaller dynamo. Before I started up the smaller machine for a test, I reinstalled the carbon brushes to determine the final rotation and then permanently installed the copper leaves as was done in Edison’s day.
Using pictures from similar machines and photos that I had taken years ago, new brush arms were constructed for dynamo no. 16. Six copper leaf brush holders from one of our dismantled 1899 transit rotary converters were installed. However, we fitted the large unit with carbon brushes for the test run. Figure 22 shows the dynamo no. 16 lower base, reconstructed brush holders, and armature, which has been painted with black Glyptal insulating varnish. Also shown is the unpainted zinc magnetic break between the bipolar field and the base.
Making the New Look Old Again
After I was satisfied that the field was intact and the red fiber field coil insulators were cleaned and repainted, the crane picked up the yoke and reunited it with dynamo no. 16. Now it was on to final assembly before painting.
Only three original copper field lugs remained, and each was stamped with an “F#” to identify the connections. Having only modern pretinned copper lugs, I matched the size and then hand stamped, like the originals, each one with its new field position identification. A trip to the sand blaster stripped off the tin, and after the squared edges were rounded, the new lugs looked like the 1880s originals.
Thanks to the old Polaroid pictures I took 30 years ago, I was able to re-form the field wires into their original positions on the terminal blocks. One by one, the lugs were soldered onto the leads, leaving a nice old patina on the lugs. Using historically accurate materials like friction tape, the leads were carefully taped and bolted onto their final positions (see Figure 23).
For historical reference, the old field leads on the smaller dynamo, which were not destroyed by thieves, were found with the original insulating tape on them. I left the original tape in place so that one can see how these machines were constructed so many years ago.
Once the bipolar fields for dynamo no. 16 were complete, the base and armature and the fields were reassembled. The five-ton (4.54-metric ton) crane strained under the load, but as each piece was installed, the dynamo took on a new life (see Figure 24).
Copper bus work that leads from the lower armature brush connections to the upper yoke terminal blocks was formed and installed (see Figure 25). Everyone in the shop was anxious to do a full test run to hear what these dynamos would have sounded like when running.
A Great Dynamo, but a Miserable Motor
Thomas Edison and his fellow “wizards” at the Menlo Park laboratory developed this type of dynamo design back in the late 1870s. It was a marvel of engineering as it turned mechanical energy into a somewhat stable source of dc. When supplied with power from a dc source, the dynamo would run as a dc shunt motor, a very bad shunt motor that spits and sparks. Edison took one of the smaller dynamos, turned it on its side, and installed it within a frame. Wooden insulated railway wheels were attached, and Edison had one of his first electrically powered trains traveling around his Menlo Park complex. He built two of these locomotives while he was busy constructing his 1882 Pearl Street plant in Manhattan. Work on the electric engines was stopped for others like Frank Sprague, his assistant, to pick up where Edison left off. The two locomotive frames can be seen today in the front yard of Edison’s West Orange, New Jersey, laboratory and factory complex, now a part of the Thomas Edison National Historical Park.
It’s Alive, It’s Alive!
The paint was dry and all connections were sound. It’s now time to see if these dynamos would spin. The smaller dynamo was first. Using a 17-V, 2,000-W resistor in series with the field circuit, 125-V dc from a spare substation lead-acid battery was applied. Using a compass, I verified that the north-south field was correct. A 4.5-V resistor in series with the armature circuit was energized. With video cameras rolling and with a little help, I spun the armature shaft and the 30-kW dynamo awoke from its century-long sleep. A quick check of the bearings showed that the oil rings were spinning and lubricating the bearings.
Changing the resistance of the field and armature, the machine was up to speed spinning almost silently. The repair section personnel erupted with cheers and applause! A few adjustments of the brushes to find the neutral plane to reduce sparking and the small dynamo was complete.
A few weeks later, when the large 100-kW Brooklyn Pearl Street dynamo no. 16 was completely assembled, we gathered once more to give it a spin. Using the same resistors in the field and armature, the power was turned on. Again, with a little prodding, the armature started to roll and built up speed. Another round of cheers and applause by all assembled must have sounded like the day Thomas Edison fired up the original dynamos at Pearl Street. Many were in awe to see such a sight. A piece of history, our history, restored and brought back to life (see Figure 26).
A New Respectful Home
The smaller dynamo was moved to our New York Transit Museum and put on display in our new electrical exhibit in late October 2011 where visitors will be able to see the connection between this machine and Edison’s early efforts in electric railroading.
As our transit rotary converters are much too large for the New York Transit Museum displays, the small 25-kW rotary converter will be restored some time in the future and placed on display to represent its much larger 1,000–4,000-kW cousins.
The completely restored Brooklyn Pearl Street dynamo no. 16 proved to be too heavy for our transit trucks to transport. Con Edison’s master rigger, Kevin McGuire and crew, using a 30-ton (27.2-metric ton) crane and flatbed truck, came to Pitkin Yard and picked it up like a toy (see Figure 27).
Its permanent place of honor is on the main floor of the Con Edison Learning Center, giving all employees and visitors a historic view of electrical machinery that first lit up New York City. This will serve as a proud reminder to all that our modern extensive generation, transmission, and distribution systems had their humble beginnings with these machines (see Figure 28).
Members of IEEE and Con Edison joined me to inspect the dynamo restoration work, and all were very pleased with and impressed by the historic display. To top off the restoration, Con Edison’s shop in Westchester cast a replacement builder’s plate from photos that I furnished. Old Edison dynamo no. 16 is finally home (see Figure 29).
I wish to thank all of the volunteers at the MTA NYCT Pitkin Yard power repair shop who assisted me in these restoration projects. A job well done!