Ken,
Ray outlined this in one of his docs with the pulse produced from the circuit compared to a Kato controller. It was about half the current and not the hard pulse of the contact switch. The cap discharge had a rapid up then slow decline after the peak, not just staying level. This he thought would help give the better coil action and less oscillation (humming) and bounce back. Also requires less power for doing multiple throws at once (he had a lot of circuits for reset of a panel with power up or hard ladders).
Cheers
Jeff
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On Jun 7, 2021, at 2:32 PM, Ken Harstine <kharstin@...> wrote:
?I don't know what the length of the pulse is that Kato controllers send.? That would determine the minimum value of the capacitor somewhat.? The only reliable way to know would be to check for heating of the turnout motor when thrown.? In general you want it to be as high as possible but not so high as to cause melting.? This would involve a lot of experimentation to arrive at with any provision.?
Pulse length matching does not really work either.? The Kato controller will produce a pulse at full voltage for a certain length of time.? The capacitor circuits provide an exponentially decreasing voltage over a known time period.? So the pulse with a capacitor should be about 30% longer to provide the same effect (sort of ).
At some point after power is applied the coil of the Kato would saturate and and only the DC resistance mentioned previously would limit current.? Once this happens the coil quits providing additional moving force.? If you watched the current with an oscilloscope you could ascertain when this occurs.? Now you know the optimum length of the pulse and could use the approximation provided by multiplying the resistance (22 Ohms per coil) times the capacitance.? If driving multiple coils you should increase the capacitance by the same multiple in order to maintain the same reliability of throw.
Regards,
Ken Harstine
Holyoke, MA
