Updated: 10 Aug 2008
Mr Jephcott's water motor added
A water motor, as opposed to a positive-displacement water engine, was a small Pelton-type water turbine, often driven from a domestic tap; these were used for many light tasks, such as driving centrifuges and stirrers in chemical laboratories or running sewing machines. Like water engines, they were eventually displaced by electric motors.
There is nothing particularly unusual about a Pelton turbine, but their use for providing small amounts of domestic power seems to be virtually forgotten. Hence this gallery of the museum.
WATER MOTORS IN THE HOME
Left: The Whitney water motor of 1906.
This is a typical water motor. The water supply is connected to the horizontal spigot at lower right, and the waste water drops out of the bottom of the casing. The Pelton wheel inside is directly connected to the pulley on the side.
So just how much power could you expect from a water motor? In a report in Model Engineer & Electrician for 2 Feb, 1905, it was stated that Messrs Whitney of 117 City Rd, London, were selling a water motor with an 8.5 in diameter wheel rated at 1/4 hp with water pressure of 60 psi. This was considered to be conservative as "a 5in wheel would normally be so rated".
Picture from Model Engineer and Electrician July 5, 1906
Some more performance data was gleaned from a catalogue produced by Gilkes of Kendal, who also made big industrial turbines. This table refers to their Number 3 water motor, which had an overall height of 17in:
Left: Water motor and dynamo combination advertised in 1912.
This outfit was intended for charging accumulators that were then used to run a radio.
Given the open construction of the dynamo, there is a big incentive to get all the pipes truly water-tight. However, if the dynamo was for charging filament batteries (HT batteries were usually of the dry-cell type) the voltage would have been low and there would have been little risk of electric shock.
From Model Engineer and Electrician Feb 1, 1912.
Left: A Lane water motor coupled to a sewing machine.
It looks like the Pelton wheel is horizontal, which was unusual. There seems to be some sort of reduction gear (probably a worm and pinion) driving the small shaft with the pulley at the end. The treadle appears to be controlling operation, presumably by actuating an inlet valve. Unfortunately the original picture is not very clear.
Note the two hoses for water inlet and outlet.
From Knight's American Mechanical Dictionary 1881.
And how much did they cost? This advert appeared in the for sale section of The Model Engineer & Electrician for October 25, 1906:
"Water Motor, 9ins diameter, brass wheel, all brass fittings; 14s,; bargains.- Hinchcliffe, 3 Castlegate, Huddersfield."
Considering that the Whitney motor above cost 26s, it does indeed appear to be a bargain.
The Model Engineer and Electrician, 15 Feb 1912, carried this ad:
The "Midget" 6s 9d; castings 3s 6d. The "Amateur" 1/8 hp, 18s 9d; castings 6s 6d. The "Whitney" 1/4 hp, 26s; castings 18s 6d. The most inexpensive means of obtaining power for all purposes.
The reference to castings needs explaining. In those days you could buy just buy the castings for steam engines etc, and do all the rest of the construction yourself.
By 1927 the cost of the Whitney motor had gone up to 45s, or 25s for just the castings.
Left: A design for a water motor.
The jet of water comes in from the bottom right. The function of the 'splasher plate' is currently obscure.
This design was published in a series of articles called "Water Motors and other Hydraulic Machines" by a Mister Joseph G Solis.
From Model Engineer and Electrician, 30 Aug 1906.
Left: Another water motor design, intended for home construction.
Here the jet of water points downwards.
A motor to this design was used to drive a washing-machine. Interestingly the article describing it was written by the constructor's wife.
From The Boy Mechanic, Book 1. 1921. The book seems to have been published by the Popular Mechanics Co.
Left: This is a rare picture of a water motor doing a job of work.
The motor is geared down by what appears to be about 8 times, to rock a developing tray for photographic plates. The exhaust water is then ingeniously used for washing the developed plates.
From Things To Make by Archibald Williams.
Left: Another home-made water motor, by a certain Mr F M Jephcott.
The jet of water can be seen coming in from the top. The drum was 7 inches in diameter by 1.25 inches wide. The buckets were made from tin and fastened on with wood-screws. Mr Jephcott reported he got the water supply through 0.5 inch pipe from a main with a 70 foot head, and this gave enough power to run a small dynamo.
From Model Engineer and Electrician, 2 Jan 1904.
Left: A fan powered by a water motor.
The water is supplied through the hose at the top. The fan can be swivelled on a ball joint at its base. It looks as though the exhaust water falls out through the middle of this ball-joint, but the original article makes no mention of how this is handled.
"By attaching a balance-wheel and pulley, the motor can be made to drive a ceiling or post-fan, or a sewing machine, with water working at a pressure of 40psi. With a pressure of 50 to 60 psi, a telephone exchange generator can be driven... The motor consumes about 7 pints of water per minute."
This fan was manufactured by the A Rosenberg Company of Baltimore, Md, USA.
From English Mechanic 9 Sept 1898, p83; originally from Scientific American
WATER MOTORS IN THE LABORATORY
An excellent source of information on water motors in the laboratory is the "Catalogue of General & Industrial Laboratory Apparatus", issued by Chas Hearson & Co Ltd, of Willow Walk, Bermondsey, London in Jan 1930.
Left: A water motor powered centrifuge .
This water motor has twin nozzles for greater power output. The water exhaust is taken out at lower right, either downwards or sideways by using the appropriate hole. The small glass cylinder at upper left is presumably a lubricator for the lower bearing, which would have borne the weight of the turbine wheel and the test-tube carrier.
These motors were capable of respectable speeds, given enough water pressure; this table was provided by Hearson & Co:
No figures were given for power output.
From the Chas Hearson catalogue.
Left: A water motor powered centrifuge: horizontal section. (looking from top)
The water exhaust is on the right. This part of the drawing is distorted as it was right in the fold of the book; the exit pipe was really circular in cross-section.
Quite why the second nozzle was set at an angle is unclear; 180 degrees seems to be the obvious alignment as it would minimise side-force on the bearings. I should have thought the exhaust could have been offset without any problems.
From the Chas Hearson catalogue.
Left: The water motor powered centrifuge worked by hand-pump.
Setup for use where there is no piped water supply; the water exhaust here is taken out from the side and returned to the bucket. The Hearson catalogue has a fine old colonial flavour, many of its products being aimed at organisations in farway places where neither mains water or electricity was available. With this arrangement, unskilled local labour could be put to work on the pump handle.
On further thought, I'm not sure that this makes a huge amount of sense. Surely it would have been easier to drive the centrifuge directly from a handle, geared up by a suitable amount? This would eliminate losses in the pump, pipework, and turbine.
From the Chas Hearson catalogue.
Left: The introduction of water-powered stirrers
An anecdote about the introduction of water-powered stirrers into the laboratory of Adolf von Baeyer (1835-1917) one of the great German organic chemists.
The Frau Professor's comment means: "That should be able to make good mayonnaise".
From a review article by John Read in Nature, 131, 294, (1933)
WATER MOTORS IN INDUSTRY
Left: A water motor in use today at Twyford water works, Hampshire
This water motor is of the usual Pelton type. It is used to dispense carbon to absorb residual impurities in the water.
The motor is the disc-shaped object at left, partly concealed by a pressure gauge. Operating pressure is 23 psi.
This explanation was given by the volunteer who provided the picture:
"The carbon plant in the corner of the mixing room was added when the diesel pumps were installed in the 1930's, to remove any possible contamination by diesel fuel. The plant is operated by a pelton wheel, driven by mains water pressure and it measured out a small quantity of carbon which the spent water from the pelton wheel washed through pipes, into the water softening tank. Here the carbon floated on the water and absorbed any oil present on the surface."
Image used by permission
Left: A water motor powered fire alarm: 1949
British buildings protected by sprinkler systems always have outside alarm bells activated by small Pelton turbines. When the sprinklers begin to discharge onto a fire, the main flow of water lifts a valve that sends a small amount of water to the alarm turbine. This has the great merit that it does not rely on a supply of electricity to operate the gong. It is also immune from frost as the pipe to the alarm is kept empty of water until the system is activated.
A bypass valve allows the alarm to be periodically tested.
From Manual of Firemanship Part 4, p103. Her Majesty's Stationary Office, 1949
Left: A water motor powered fire alarm: 2008
Alarm bells activated by small turbines are very much still with us. This picture was taken on the afternoon of the 5th of July, 2008, on the inside of one of the outside walls of the John Lewis department store, on Oxford St, London.
You can learn more on the Angus Fire website here (external link)
ON THE PELTON TURBINE
The Pelton impulse water turbine, on which most water motors were based, was invented by the American Lester Allan Pelton (1829-1908). He was born in Vermilion, Ohio in 1850 and moved to California during the gold rush. (1848-1855) Pelton worked there as a carpenter and millwright.
Water turbines and water wheels were not new, but Pelton's innovation was to shape the buckets on the wheel so that the impinging water was reversed in direction, thus extracting more energy from it. For greatest efficiency the buckets are receeding at half the speed of the water so that the water is brought to a stop.
The Pelton wheel was first used at the Mayflower Mine in Nevada City, California in 1878. By 1879 he had tested a prototype Pelton wheel at the University of California.
In 1887 a miner attached a Pelton wheel to a dynamo and thereby produced the first hydroelectric power in the Sierra Nevada Mountains.
A patent was granted to Pelton in 1889, and he later sold the rights to the Pelton Water Wheel Company of San Francisco.
The Pelton turbine works best with relatively small amounts of water at high pressure. It has a high energy conversion efficiency, usually over 90%.
The water-motor lives on! See:
This describes a small Pelton turbine. See page 52.
More info on it: www.watermotor.net
Water motors are often used to power irrigation equipment. See: www.kifco.com
Typing "water motor" into Google does not yield much. "Micro-hydro" however brings in a lot of info about modern small turbines.