The Folsom Power House 1895

The Folsom Power Plant 1895

The Folsom Power House and transformers. Folsom, California
(Notice the round port on the 2nd floor which allowed for the original Stanley air-cooled transformers)

The Folsom Power House was one of the earliest alternating current power plants in the country. In 1895 it opened and operated as the longest transmission lines of any power plant in North America. It produced power and sent it 22 miles to Sacramento. That was the longest power transmission in the U.S. until that time.

The powerhouse is open for free visitor tours Wednesday-Sunday, 12pm-4pm.
Group tours can be scheduled at (916)985-4843

About this Power Generation Site:

Notable features: First commercial 60 cycle 3-phase power system (now our modern system), was the farthest commercial power transmission until the next year (1896), when Niagara Falls power was transmitted using a GE system to Buffalo from the 1895 Westinghouse powerhouse.

Frequency: 60 cycle
Three-Phase, Alternating Current
Power Transmission Length: 22 miles at 11,000 volts using #1 wire
Power system built by: General Electric
Notable Engineers: Elihu Thomson (generators), William Stanley (original transformers), Dr. Louis Bell (became chief transmission engineer)
Maximum Power Output: 3000 kW

Watch the videos of the generators and transformers below:

Generator and Turbine Areas: (9:24 min.)

Transformers and Power Transmission Lines: (4:30 min.)

There will be more videos in the future of the switch panel, governors, and lower power house.

Photo Gallery :

The generators were built in Schenectady, New York.

This ammeter is non-shunted, it takes the full load from bus bar.

Ammeter photos by Bill Henning

The ammeter Another invention of the great Elihu Thomson.

Brushes: brush carrier, brush holder, feed spring (these were burned by an overload just before closing the plant)
See more about this burned up generator in the end of the video above.

Four pole DC Excitor, most likely shunt wound

Winding bars and field coil splice

Name Plate:

GE Alternating current generator Type AP No 1376 Class 24 760 800 Form A
Volts no load -- full load 830 Amperes 542 Speed 300 Patented Jan 13 1880 Oct 10 80 March 25 84 Apr 222 89 March 4 90 Marc 14 1892 Apr 4 82 Nov 14 1892 Patents applied for General Electric Co. Schenectady, N.Y. USA

One of North America's first commercial AC generators!

Lombard Governor

Wide view of the generator room

One of four main turbines, has gearing for the wheels, gears used to maintain speed.

Westinghouse Step-up Transformers (Oil Filled) installed later in 1917. Originally the
plant was equipped with Stanley transformers.

Switch board built with Tennessee marble

Half of the motor genset -3 phase (this is the one in the next photo above on the right) originally put in for the lower powerhouse to energize the field coils and later on this provided standby DC power.

The lower powerhouse contains a newer
generation of AC generator 1900:

DC field slip ring (the field was on the rotor) wires carry DC power from the rings to the field coils

Field Coils on the left, stator on the right. 3 phase

Shooting the interview with Bill Henning, PH Docent

Folsom Power Houses (upper and lower) as seen from across the River

Folsom Lake is created by the modern hydroelectric dam that replaced the historic Folsom Power House. This lake is formed by the American River and extends into the foothills of the Sierra Nevada mountains in central California. The river is fed by an enormous watershed that peaks at the mountains just west of Lake Tahoe.