Two current generators (actually voltage generators for my purpose, since the coil has a fixed resistance). iGen 1 is
Fire; iGen 2 is
Hold.
Both supplied from a 20 V, high capacity source.
Each is actuated by a low current, timed pulse, orginally from the flywheel.
Both timed pulses act at the same moment. But Fire acts briefly whereas Hold continues longer. Fire is about 0.5 ms but can be varied; Hold is about 1 ms but is more variable. (ms is 10^-3 sec).
The solenoid is 4.5 Ω, ~2 mH,.
I reckon we need ~5 A to Fire (=pull plate across space), ~2 A to Hold.
In the lower figure, the timer could be acting on the iGens attached below the coil.
What do you think? Do-able ?
Malc