Smiths Sectronic Mk II Movement
(Impulsed; moving coil; electronically
The Smiths Sectronic Mk II movement is
basically similar in operation to the Sectronic
Mk I. The construction of the balance and coil assembly is slightly
different in that the coils are in the same plane as the balance and not
at right-angles. There are two separate coil assemblies each with a concentric
trigger coil and impulse coil (the two trigger coils are in series with
each other as are the impulse coils) and therefore there are two trigger
signals and two impulses in each direction of the balance's swing.
There are still three hair springs to pass current to and from the coils
so there is no real saving in complexity of construction over the Mk I.
The hands are driven by a rack lever escapement working in reverse.
||one LR14/MN1400/C size cell
Copyright Text & Pictures - Martin Ridout. Last updated