Jensen Model # 51 Steam Power Generation Plant
Jeannette, PA, USA - Manufacture date: 1996
Bore = 1", Stroke 1 1/4", Flywheel diameter = 5"
Style: Double Acting, horizontal

Dimensions: 34" length x 24" width x 30" height
(includes wood base)

Jensen Model #51

s the Webmaster for the Jensen Steam Engine Manufacturing Company, they naturally have a special place in my collecting activities.

The limited edition Model # 51 is extremely difficult to acquire for a private collection. Jensen hand builds only 2 of these engines per year. They tend to, almost exclusively, end up with electrical power companies as public relations displays or university physics departments as teaching aides. Mine is a bit unusual in that the water tower is labeled "Jensen" instead of bearing the name of a power company or school. Needless to say, this engine is the Crown Jewel of the collection and will hopefully pass down through the family for many years.

The motor of the 51 is a show piece by miniature steam engine standards. The cast iron base is massive and ruggedly constructed, yet machined to fine tolerances to accept the highly detailed brass components that make up the assembly.

The 5" flywheel is turned by a one inch bore cylinder, complete with an open window cross head guide. It exhausts to a stainless condensation stack that really amplifies the chuffing sounds given off under a heavy work load. A working flyball governor lets you adjust the 51 to run at a preset self regulating speed.

With its multiple PTO pulleys, driven at 1/25th HP, this machine can be adapted to drive nearly any accessory you can adapt to a drive pulley.

The 51 Motor

The 51's 5 Inch Boiler

The boiler of a 51 is 5 inches in diameter and constructed from nickel plated brass. For heating, it utilizes 3 immersion rod style heater elements which are controlled by switches on the power plant's control panel. Combined with the mechanically powered feed water pump, supplying fresh water from the water tower, the 51 is capable of up to 8 hours of run time at low speeds, making the engine a perfect for public displays.

A well seasoned 51 will run on as little as 6 pounds of pressure with steam in reserve for those high speed temptations

Cylinder and Governor Valve Details

The detail of the 51's design and the high caliber of craftsmanship by Tom Jensen, Sr. and now, Tom Jensen Jr., separates it from the world of toy steam engines by a major leap.

Feed Water Pump

With such items as the linkage driven water pump and oiler cups, its obvious that no corners were cut during the design and manufacture of this masterpiece.

The 51's Electronic Control Panel

The Power Plant controls were a touch of genius supplied by Randy Calhoun, who designed and still does all of the control installations for the 51's. The power plant is fully able to demonstrate the various electrical effects which come into play as you put the 6 volt AC/DC generator to work under various types and combinations of loads.


The AC / DC Generator and Saw Motor

The various loads offered on the 51 include a DC saw motor and the highly recognizable Jensen Lamp Post, which lights under AC and DC voltages to produce different effects on the meters. Other, mechanical loads can be added via the PTO pulley.



A Pair of Jensen Model #51's

For a brief period in time, I became one of only a very few steam addicts to ever actually own 2 of these behemoths at the same time. (not usually recommended due to the amazing space requirements) An email appeared in my box one evening, asking if I'd be interested in purchasing a Jensen model #51. The sender went on to explain that his father had purchased the engine in 1983 and had passed it down upon his death. The owner was downsizing his accommodations and had quickly determined that a Jensen model #51 simply does not downsize gracefully. After a bit of negotiation, I agreed to purchase the engine and drove to Florida to pick it up.

Steam collectors find that parting with a steam engine is difficult at anytime, but it's doubly hard when it has a sentimental family attachment to it. I arrived at the fellow's home, consummated the deal and the model #51 and I soon departed Florida, but not before solemnly promising that, if sold, the engine would go to a "good home".  

Once back at home, a bit of minor restoration work was undertaken to return the engine to pristine condition and to put it back in excellent running order. I now have a completely new level of appreciation for the ingenuity of Tom Jensen Sr. and Randy Calhoun. I knew these engines were well made, but the level of attention to detail which went into the designing and building this marvelous engine can only really be seen from the inside. The skills required and the care taken in manufacturing a model 51 are simply unsurpassed.

I've long since sold the second Jensen #51 power plant, but I kept my promise to the previous owner and made sure that it found its way into the hands of a voraciously loyal Jensen collector. The engine now holds a place of honor in one of the most prestigious Jensen steam engine collections to be found anywhere. I hear it's kept well oiled, literally steamed every day and is said to be rather happy there.


Stuart Beam  -  Reeves Tangye  -   Williamson   -   Stuart H9   -   Stuart D-10   -   Jensen 51
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