DescriptionHamilton Important & Rare EM-1 Prototype, The First Complete Prototype Electric Wristwatch From The Personal Collection Of René Rondeau
Case: gold filled, two body with insulated metal plate screwed to the back over the battery, 33 mm, beveled and tapered lugs
Dial: black, radial golden Arabic numerals and dart markers, jagged "electricity" bolt below the Hamilton signature, gold Dauphine hands, gold seconds hand with red arrow tip
Movement: Electromagnetic model 1 by Fred Koehler, semi-circle layout for the coils, conventional size balance wheel
Note: This historically important, museum quality watch was the first working electric wristwatch. In October, 1952, Fred Koehler was assigned to develop a wristwatch based on his electric clock movement. To fit in the small Hamilton-Illinois automatic case, the coils were redesigned in a long semi-circle which surrounds the movement, rather than the two barrel-shaped electromagnets used in his clock. The balance wheel was conventional in size, leaving room for the battery to be incorporated into a hole in the case back. The prototype was completed on November 15, 1952, three months before the PM-1 (Permanent Magnet Model) was cased. The electromagnetic project was shelved and no further prototypes were made when the Hamilton research division and management opted to instead develop the PM-1 model in a controversial decision. When Fred Koehler retired in 1961 the company let him keep his prototype electric clocks and the EM-1 prototype electric watch.
This watch was acquired directly from Fred Koehler in 1988. it is accompanied by original factory photos of the disassembled watch and of a young Fred Koehler. Also, new and old patent drawings and papers relating to the EM-1 and a newspaper obituary from his death 4/13/91.
Type: Hamilton Important & Rare EM-1 Prototype, The First Complete Prototype Electric Wristwatch From The Personal Collection Of René Rondeau
Dial: black, Arabic numerals
Hands; gold Dauphine hands
Metal: gold filled, insulated metal back plate
Case Info: two body back plate held by screws
Case Width: 33 mm
Watch Movement: Electromagnetic model 1 by Fred Koehler, semi-circle layout for the coils, conventional size balance wheel
Circa: completed November 15, 1952
Condition: dial is very good, case is very good, movement good - a prototype - non running
*Heritage Auctions strongly encourages in-person inspection of items by the bidder. Statements by Heritage regarding the condition of objects are for guidance only and should not be relied upon as statements of fact, and do not constitute a representation, warranty, or assumption of liability by Heritage. All lots offered are sold "AS IS".
Fees, Shipping, and Handling Description: Miscellaneous Collectibles, Small (view shipping information)
Sales Tax information | Terms and Conditions
Bidding Guidelines and Bid Increments
Glossary of Terms
Buyer's Premium per Lot:
25% on the first $100,000 (minimum $14), plus 20% of any amount between $100,000 and $1,000,000, plus 12% of any amount over $1,000,000 per lot.
Opens about 01/02/2018
- Past Auction Values (prices, photos, full descriptions, etc.)
- Bid online
- Free Collector newsletter
- Want List with instant e-mail notifications
- Reduced auction commissions when you resell your
- Cash Advances
- More Bidders
- Trusted Experts
- Over 200,000 Satisfied Consignors Since 1976
HA.com receives more traffic than any other auction house website. (Source: Similarweb.com)