stay alive capacitors

Discuss your experiences with systems, decoders, installations, wiring, control and any general hints & tips you have found.
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stay alive capacitors

Postby scalemaster » Sun Mar 16, 2014 1:40 pm

Can any of the members tell me if this system can be fitted to non dcc loco`s . it could be very usefull for slow running shunt loco`s + passenger stock on my layout?

A small diagram showing component values would be great?

Regards Bob Cummings[scalemaster]

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Re: stay alive capacitors

Postby nigelcliffe » Sun Mar 16, 2014 5:28 pm

I've seen a scheme for doing it (and a demonstration proof of principle), but it was complicated and introduced all sorts of "interesting" running issues, such as massive momentum implicit in the behaviour of the locomotive.

Unless wanting an "experiment with electronics" project, then its either DCC or battery radio operation. Simple radio systems are not particularly expensive and can work alongside DC (or DCC) power through the track.

- Nigel

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Re: stay alive capacitors

Postby KK92 » Mon Mar 17, 2014 10:23 am

Unless you use some electronic trickery that detects when the loco looses electrical contact the stay alive capacitors would work like a battry if only a small one.

What would happen is that the capacitor charges and then would power the motor either when the loco looses contact or the controller is turned down.

Be aware that a single stay alive capacitor (or a bank of these) will only work in one direction on a normal DC motor. You would need two of them an some electronical device to avoid both capacitor shortening out each other.

It is a different matter with DCC here the capacitor(s) deliver the power to the input of the decoder. The direction and speed controll happens here behind the capacitors.

I would say that the amound of electricery would equal that of using DCC.

Does anyone know whether a stay alive capacitor would work with a DCC decoder used analog?


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Tim V
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Re: stay alive capacitors

Postby Tim V » Mon Mar 17, 2014 4:47 pm

I always turn off DC capability in my decoders.
Tim V
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Re: stay alive capacitors

Postby grovenor-2685 » Mon Mar 17, 2014 8:33 pm

Does anyone know whether a stay alive capacitor would work with a DCC decoder used analog?

The Stay alive caps are on the output side of the decoder rectifier so will work, however, at low speed when you really want them they will only be charged to 5 or 6 volts so will have very little effective energy stored and the hold up time consequently very short. It will be OK at full speed when you don't need it :)

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