Re: Master Clock contact spark quenching
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When the switch breaks, current is still flowing in the magnet coil, as the magnetic field collapses in the iron core, reverse current is induced. Since the circuit is broken the voltage rises very high and a spark may jump the gap. When synchronomes were in service a resistor was used to drain the current and avoid the voltage reaching a level that would spark. The modern way is to use a silicon power diode (e.g. 1N4001) mounted in reverse across the switch. These were not available in the clock’s heyday, hence the resistor. A capacitor might delay the rise of the peak, but either a resistor or diode is really the way to go.
On Jan 6, 2021, at 23:23, Andrew Nahum <andrew.nahum@...> wrote: