The Felsa 790, here in red-golden color, debuted in 1953ies and is compareatively rare, since Felsa produced it in lower quantities (only 69.500 items) than the caliber 1560, which was made at the same time.
As all Felsa movement, the Felsa 790 is very well made, too.
All important bearings use rubies.
The classical gear train construction requires a center minute wheel, which is directly driven by the mainspring barrel. It is beared below an own bridge.
The rest of the gear train is pretty much standard: The central minute wheel drives a double third wheel, which engages with both gears into the center seconds pinion and with the lower of the two gears into the seconds wheel. Because of this, the center seconds wheel does not flap.
The final wheel is, as expected, the escape wheel, made of steel. It is blocked by a swiss pallet lever escapement.
The golden Glucydur screw balance is really beautiful!
It beats slowly with 18000 A/h and can be regulated with a long regulator arm.
The balance wheel is shock protected by two Incabloc bearings.
A little speciality of the Felsa 790 construction is the crown wheel: It is located on the inner side of the gear trian bridge, which also bears the mainspring barrel.
The tiny ratchet is located at the outer edge of the base plate and is pushed with a spring against the ratchet wheel.
Felsa kept the “Bidynator” principle: The oscillating weight drives the transmission wheel of the lever changer. Depending on its direction, it drives either the left of the right large exchange wheel. The pawl of the left exchangle wheel ensures, that only revolutions in one direction are possible.
After the right exchange wheel, a reduction wheel with a ratchet clutch is used to drive the ratchet wheel of the mainspring barrel and to release it, when the movement is manually wound.
The oscillating weight, which unfortunately is missing on the specimen shown here, is axle beared. The axle is mounted with three screws on top of the gear train bridge.
On the dial side, you see the yoke winding system, the Incabloc shock protection and a partial minute scale, which was used to adjust the movement prior to casing.
|Size:||11 1/2''' (measured: 26,0mm)|
|Number of jewels:||22|
Glucydur screw balance (two legs)|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||3 hole(s)|
|Production period:||1953 - 1960|
Flume: 1957 57|