Pendon museum use (or used) a high frequency AC power source for the lighting in their trains. I believe they rely on the inductance of the motor to stop it interfering with the motor and cooking it. I've always wanted to do something similar with 009 trains buy I'm not sure if the smaller motors are capable of protecting themselves from being fried. Anybody got any ideas please?
I think DCC would solve all these problems. I don't think it fries motors at all and i've seen some marvellous layouts with it on. There's a brilliant 009 colonial layout which even has sound which i saw at the Winchester AGM.
cheerz
One of you two should have RM back to 1963 or so; there was an article on HF lighting techniques there.
Of course you could always take Ted Polet's route and stick batteries in your stock! :D
Dave.
I think the motors generally used in OO9 should block high frequency AC just as well as those used in 4 mm scale standard gauge models. However, I agree with Gollum that these days DCC is a much better solution. The control of features such as lighting is built-in to DCC receivers, so it's off the shelf so to speak. Whereas, with high frequency AC lighting you will be constructing everything from scratch.
Richard
Another solution is to use small batteries to power the lighting. There are a few re-chargeable batteries on the market which are capable of powering a train and they won't 'flicker' with track pick-up. Bert van Rhijn has just written a very good article in the July 009 News.
NMB
Hello everybody,
I'm experimenting with button batteries at the moment - the limiting factor seems to be the ratio of batteries to LEDs. 6 v ( 4 pretty hefty batteries) only just about lights 2 LEDs with 1 resistor (only 150 ohms!). Anyone know what the minimum resistance it needs to stop an LED frying itself ???
Live long & prosper!
Hi All
Sorry to be so slow replying to this - I've only just noticed it. You need a blocking capacitor (condensor) to stop the dc motor "seeing" the ac current. Therefore the power has to be split in things like my trams which use this system so that car lights stay on at stops altjough this wouldnot apply for a train and coaches. Gaugemaster make a commercial HF unit which is what I have used.
Regards
Pete
I think it is the other way round. Capacitors block DC and pass AC as they are effectively two conducting plates separated by an insulator. You want a capacitor in series with the light bulbs or LED circuit to block the motor supply current.
Inductors are like flywheels for electrical current. An inductor in series with the motor (or the motor winding itself) will take "too long" to respond to the rapidly alternating High Frequency lighting supply and not "see" it. The capacitor you have across the terminals of a motor are there to short out the high frequency electrical noise that may be generated by sparking etc in the brushes and commutator that can cause radio interference. This capacitor may also form a short for the HF lighting and may need to be removed.
The books on Model Railway Electronics by Roger Amos include coach lighting circuits.
Hi All
Yes, you're right it should be the other way round. I was in a hurry. The blocking capacitor stops the lighting "seeing" the dc while the high frequency ac means the motor does not respond.
Regards
Peter
Quote from: engerth399 on January 06, 2009, 09:46
Hi All
Yes, you're right it should be the other way round. I was in a hurry.
Easily done! Done it myself. :-[