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Prototype Froment Electric Motor c. 1844

The Froment electric motor invented in 1844 was the first electric motor designed to do WORK i.e. drive machinery, as opposed to simply having a moving part that turned with the application of an electric current (only supplied by batteries at the time). Although highly inefficient the Froment motor represented a very important technological step as it was a totally new potential power source for industry which at the time had only water, wind-mills or steam engines as alternatives. In fact it was some years before electric motors could compete with steam in economic terms because the only electrical power source before the development of dynamos were batteries and in the 1840s it was estimated that a steam engine powered by coal was seventy times cheaper for the same work output compared to an electric motor fueled by zinc and carbon batteries. The Froment motor was manufactured for many years but this example is, I believe, almost certainly the prototype for the following reasons: 1. The wood frame is highly unusual and significant. The only other examples of electric motors known to me with wooden frames were Wheatstone's first electric motor made in 1840 and now in the Science Museum, London and some experimental motors from the 1830s. It is pertinent to note that Wheatstone's second, third and fourth electric motors were all made with iron metal frames. So just how many Froment motors would have been constructed with wood frames before switching to metal ones, one? two? three? 2. There was an error made in constructing this motor. The base was motised in the wrong position to take one of the upright frame sides and was plugged with wood and re-mortised (see photo) such errors are not uncommon in prototypes but inconceivable in the manufacture of a number of units - even a very small number and this gives very strong credence to this example being the first prototype. (For a similar example of woodwork being modified on a world first prototype see details of the box of the Hooper Ether Inhaler sold on this web site). 3. The brushes in the form of little casters are extremely primitive and would have been modified very quickly for a more efficient means of connecting to the commutator. 4. In the early 1840s it was thought that the efficiency of an electromagnet was increased by placing it at an angle to the armature. This was quickly found to be erroneous so the steep angle of about 60ยบ of the two electromagnets indicates a very early example. 5. The winding of one of the electromagnets in 'bunches' is indicative of experimentation. It is also worth adding that the earliest Froment motors manufactured with cast iron frames had four electro magnets. A very early modification of introducing a further two magnets, making four electromagnets in total makes sense so this is a further indication that this motor pre-dates the manufactured examples. The Teyler Institute has a four magnet example made to the 1844 design by Froment's son-in-law, P. Dumoulin-Froment some years later, which also (I'm delighted to point out!) uses similar 'casters' as brushes for the commutator. Other points worth noting are the wood cores of the armature and commutator and the general construction of the motor using nuts and bolts, very reminiscent of steam engine construction, (ditto the cut of the cog wheels), which was known to influence the construction of the earliest electric motors. (Some early electric motors were even made with beams like little steam engines. Known as reciprocating electric motors examples are in the Smithsonian Institution and University of Texas). Finally note the 'flat' on the arbour to take a pulley wheel to drive a belt. I've had my eye on this electric motor for many years since I first saw it in a private collection and now that I've finally managed to buy it I am delighted to be able to offer for sale on my web site. I think I can state with a fair degree of confidence that this is a 'one-off' opportunity. I think it is exceedingly unlikely that I will ever be able to offer another electric motor of this importance or age again. Base 12.5" (31.5 cm) x 9.5" (24 cm) height 14" (35.5) weight 30 lbs (13 kg)

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