Power Station 1908
power station used for early experiments by C.P.
Steinmetz's Experimental Power Line
Schaghticoke-Schenectady power line was a testing
ground for new power grid technology
Steinmetz, pioneer of AC power started a new project in
1908. His goal was to make a new power transmission system
to rival the Westinghouse system. He connected the small
hydro-power station at Schaghticoke (built in 1902) with
Mechanicville 8 miles away. He invented the monocyclic 3
phase system for power transmission. On the transmission
lines there were 3 wires, one with a phase of 270 degrees,
and two with 90 degrees. They operated at 40 cycles per
second. The line operated at 32,000 volts. The experimental
line was linked with the existing Mechanicville-Schenectady
The new system had the advantage of being able to run
an electric motor without need for a centrifugal switch.
This would allow for smaller electric motors, and no failures
of electric motors caused by the sticking of the starting
clutch (a common cause of electric motor burn out).
centrifugal switch connects a starting winding in
the circuit until the motor is up to speed. Then the switch
opens because this winding is not designed for continuous
advantage was that it was a current constant line: the power
line was self adjusting. If you use more power, the voltage
would rise to meet the need.
Steinmetz's new system had the disadvantage of not handling lighting
strikes well. When lightning struck the system, the current was
sent down the line.
a Monocyclic Power System Works:
Invented by C.
P. Steinmetz in Schenectady, NY
"The monocyclic system is essentially
a single-phase system, consisting of two wires in combination
with a third auxiliary, or teaser wire; the main lines being
used for supplying lights, while the the third wire which
carries the intermediate, or displaced, current, is used
together with the main lines for supplying power to polyphase
motors.The teaser wire need only be run to the motors. Indeed,
the teaser wire need not start from the generator,but may
start from any motor, or multiple-circuit apparatus of the
system. The motors operate practically the same as polyphase
motors. As the lights are connected to the single-phase
circuit, there is no possibility of unbalancing. The monocyclic
generator can be loaded to the fullest extent with either
lights or motors, or partly with the lights and partly with
motors, in any proportion.
It has been noted that the regulation of polyphase generators
varies with the inductive character of the load. The monocyclic
generator, when designed with a shunt and series excitation,
possesses the superior advantage of the automatically compounding
for all kinds of load. The power wire of the monocyclic
system supplies the magnetizing current to the motors, which
current is returned over the main wires, adding to the magnitude
of the current in one lead, and reducing it in the other.
The commutating device is placed in the main carrying the
largest current. As the increase over the normal depends
on the motors, ... "
from Standard Polyphase Apparatus and Systems 1899
by Maurice Agnus Oudin
Over time Steinmetz's power line was later linked up with other
small hydro projects like Victory Mills, 14 miles to the north.
The Hudson Transmitting Power Company owned these systems.
The place where Steinmetz's line crossed
the Hudson River within view of the Mechanicville power station.
Beginning of the Schaghticoke transmission
line showing power station in the background
Steinmetz's project was stopped due to the fact that Westinghouse
had already controlled so much of the market that it was going to
be impossible to break into the market with this new system. The
powerline was then converted to a 3 phase Delta system in the 1920's.
the power line operates at 34,500 volts. The power station at Schaghticoke
produces 16.4 megawatts.
W. Hull of GE worked on HVDC transmission from Mechanicville
to Schenectady, and converting the 40 Hz to 60 Hz.
Multi-phase power transmission research continued over the years.
Twelve-phase was the most ever created and that research was done
Oliver Winn at General Electric. The 12-phase system worked
well when converted to DC, it made a smooth transition.
Early Power Transmission History Sites:
to History of Electrification and Transmission Page
Power Station, Mechanicville, New York 1897
Powerhouse, Folsom California 1895
Redlands Mill Creek 1 powerhouse Redlands,
Barrington 1886 The first AC power distribution system using transformers
Hawkins Electrical Guide #5
Theo Audel and Co. 1917
Harnessing the Hudson by Dr. Paul Loatman
The General Electric Story by the Hall of Electrical History
Men and Volts by John Hammond
History of High Voltage Direct Current Transmission by Owen Peake
Monocyclic Power, A Novel but Short-Lived Power Distribution System
by Thomas Blalock, IEEE
Photos: M. Whelan, and Hawkins
Electrical Guide #5
Article by: M. Whelan, reviewed
by Tom Blalock
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