Subject:
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Re: Does anyone know how to modify a train controler?
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 25 Oct 2001 16:19:15 GMT
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Viewed:
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1198 times
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> > > > 9v (7.5 ~=~ 80% of 9) ?
> > >
> > > I think you've missed the point slightly.
> > >
> > > We are talking about 9 volt controllers and power supplies to the unit.
> > > The STANDARD power supply for the 9 volt controllers is 12 VOLTS AC! It
> > > turns it into DC 9 VOLTS inside the unit.
> > >
> > > When your using the less then 12 volts mode you're STILL taking the 3
> > > volt hit inside and the end result is a lowered total output.
> > >
> > > In your example, 7.5 volts is aprox 5 volts. That's not much for the
> > > train. It could degrade even more at low voltages. I'm not sure. I
> > > haven't had a chance to try it yet.
> > Also, the voltages that are output in the 6 steps do not increase linearly.
> > One might think that the settings (based on 9v max) are 1.5, 3, 4.5, 6, 7.5, and
> > 9, but they aren't. I cannot remember where the scale starts on the speed
> > controller, but I think it is around 3V. Below that setting (3V?), there just
> > isn't enough juice to get the motor moving.
>
> You are right. I think it's 2.9 volts or there abouts. Anything less and
> it's too low.
>
> Inside is just mis matched resistors. As you turn the knob up it just
> pulls more of them out of the circuit.
My solution was to add a resistor over them (picture later).
Yes the lowest is 2.9V. By adding a resistor over them all makes i affect
the higher settings more than the lower ones. This is right for less that
2.9V is not enough for the motor to move.
And there is no danger by supplying 12V or more, unless the regulator is
modifyed it can NEVER give more than 9V. So one can not speed up the trains
this way.
By using another transformer it should be considered that there is a loss in
the regulator, I don't the datasheets for the LM317 handy, but guessing that
1.2 volts is lost in the controller.
Also it depends a lot whether it is AC or DC.
The regulator says that it needs 9-10V AC which is some 13-14V DC. So if
ones transformer says 9VAC it makes no difference as it is 13V DC and a
stepdown of 1.2V is 11.8V so it can still supply the full 9V.
9VDC would make maximim app. 7.8V. But it would also make it so, that the
last steps will be the same.
Therefore a resistor still uses the full adjustment possible.
See you in 2 weeks
Sonnich
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Message has 1 Reply:
 | | Re: Does anyone know how to modify a train controler?
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| (...) Well, I want to modify mine to output a constant 9V for powering technic motor gadgets (e.g. point motors). I've just got some polarity switches, and I want to fit them on my controller. I've been advised to wire up my own 9V regulator with a (...) (23 years ago, 26-Oct-01, to lugnet.trains)
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