[GreenKeys] [Bulk] Re: NYC subway power

[Peter Gottlieb]

Con Ed only within the past few years stopped supplying DC.  A lot of old 
elevators used it.


On 8/10/2011 5:51 PM, Jack wrote:
> In the early 1980's, when I was with AT&T's AMPS cellular
> company (pre-divestiture) I surveyed a 10 floor warehouse-type
> building in
> Manhattan for a cell site. The entire building was wired for
> DC! Somewhere on the upper East side.
>
>
>
>
> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net
> [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Peter Gottlieb
> Sent: Wednesday, August 10, 2011 4:43 PM
> To: nagle at animats.com
> Cc: greenkeys at mailman.qth.net
> Subject: [Bulk] Re: [GreenKeys] NYC subway power
>
> Fascinating.  I worked in the city for many years, commuting in via
> Metro North from Westchester.  I still remember the generation plant
> in Yonkers with their big generators which you could see spinning in
> the summer when they had the huge doors and windows open.  I also
> remember the old stations with the flickering 25 Hz bulbs where they
> used 5 120 volt lamps in series, like Christmas lights.  One burned
> out and a whole bunch went out.  Glad to be out of that rat race and
> back to real engineering.
>
> Peter
>
>
>
> Aug 10, 2011 05:24:06 PM, nagle at animats.com wrote:
>
> On 8/10/2011 1:30 PM, greenkeys-request at mailman.qth.net wrote:
>> Bruce Gentry wrote:
>>>> Larry Tighe wrote:
>>>> The subway AC distribution was 25 cycles, and the bulbs did
>>>> flicker quite noticably. They were indeed left hand thread, and
>>>> in groups of 5 wired in series for 600 volts. If the AC power
>>>> failed, the station master could switch them to take service from
>>>> the third rail at 600 volts DC.  I think all of them are gone
>>>> now, but they were there in 1992.
>       Assuming anybody cares,
>
> Yes, the BMT and IRT parts of the NYC subway system were once 25Hz.
> Distribution was 11KV, 3 phase, and was converted to 600VDC traction
> power at AC to DC substations using rotary converters, later huge
> mercury arc rectifiers, and finally solid state diodes.  Unusually,
> 3-phase power was converted to 6-phase power in special transformers
> before rectifying, to reduce ripple, and hence unwanted vibration in
> the DC traction motors.  The original generators ran at only 75RPM,
> driven by reciprocating steam engines with a 42-inch piston and a
> 60-inch stroke. Each engine drove a 5 MW generator, and there
> were 11 engines in the original 1904 plant.
>
> In 1915, there was an upgrade to turbines, with 30MW per turbine.
>
> The power house building still stands, at 59th St. and 11th Av,
> an impressive, ornate building. Con Ed currently owns it and
> does some steam generation there, but no electricity is generated.
>
> NYC subway traction power is still 600VDC, but the AC system is
> all 60Hz now.
>
> The original system is well documented:
>
> http://www.nycsubway.org/articles/powerplant.html
>
> The AMTRAK northeast corridor is still 25Hz.
>
>       John Nagle
>
>
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