blinking lights

[hunter2115]

Does anyone know if there is a way to reduce the blinking of the lights in my track-powered passenger cars when crossing #6 crossover track sections (even when going straight through)? Would polarizing the frog as described in the instructions help?

[Nigel]

You could put a capacitor and voltage regulator in the cars - or a battery like Rapido does in thier passenger cars.

personally, I like the idea of low voltage lighting (bulbs or LEDs), with a voltage regulator with a large capacitor.

[Joe Satnik]

Dear Hunter,

Nigel's solutions are nice because you don't have to worry about frog shorts from wiring errors or operator goof-ups. 

I suppose you could put an 1156 automotive tail lamp in series with each of the frogs to guard against shorts.  (2 bulbs needed.) 

Regarding polarizing the frogs (if you must): 

You already have 2 controllers to move the 2 sets of points into their crossover positions. 

I can't think of a reason you would want to keep 1 set of points mainlined while the other divergent, so you could just use a DPDT switch on your panel next to your 2 controllers.  Mount and wire the 2 controllers and the DPDT switch so that all three go in one direction for mainline operation, and the other direction for crossover operation.   

Back of DPDT switch:

1 2 3
4 5 6

For DCC operation:
North rail power -->1 and 6
South rail power -->3 and 4
North frog -->2
South frog -->5

For DC Block operation (Cuts/mods for isolating the 2 mainlines)

North track North rail power -->1
North track South rail power -->3
North frog --> 2
South track North rail power -->6
South track South rail power -->4
South frog -->5

Label the paddle position when 1-2 and 4-5 are connected as "crossover".
Label the paddle position when 2-3 and 5-6 are connected as "mainline".

Hope this helps.

Sincerely,

Joe Satnik

[Jim Banner]

A large capacitor, or worse, several large capacitors are okay on dc but can play havoc on DCC.  I used this idea on a layout driven by a Power Station 8 (8 amp DCC booster).  With four or five of these passenger cars on the tracks, a short would shut down the booster and then the booster was unable to recover.  It saw the capacitors as momentary short circuits, which lasted long enough to shut the booster down again before it could fully recover.

A better choice for DCC is a rechargeable battery with a limited current charger.  About 90 to 95% of the time, the battery receives a small charge, about 10 to 15% of what is required to light the lamps.  But if the wheels momentarily lose pickup, then the battery provides full lighting power for that moment.  In the circuit I have in mind, the battery sets the voltage both during battery powered lighting and during track powered lighting, so there is no tricky circuit adjustments and no flicker or change in brightness when it switches from track to battery and back again.  No flickering, no dimming, and works with both incandescents and LEDs.

An easier choice, again for DCC, is to rectify the power from the rails and feed this to the lights through a diode.  Also feed the lights from a battery through a second diode.  The lights will change brightness somewhat as they switch from track to battery power, but not objectionably so if you use LEDs.  And battery life will be extended to about 10 times what it would be with no track pickup.  No flickering on and off, long, long battery life - but you have to use LEDs.

These two circuits will works on cross-overs, dirty track, or anywhere else you have less than perfect rail contact.  I don't have time to draw circuit diagrams this morning, but if you want them, let me know.

[WoundedBear]

Jim....it's funny....everytime I read one of your posts, I get a little smarter.

I have a whole file of your materiel that has been cut'n'pasted into notepad.

Thanks.

Sid

[richG]

Here are some ideas. A 0.47 to 1.0 Farad capacitor is usually recommended if you do not go with the battery option. You will probably have to experiment. These circuits work with DC as well.

http://www.awrr.com/lighting.html

I bought a complete kit for the one using the 0,47 F capacitor from Jim Betz on the Yahoo SoundTraxx group for about $6.00 including shipping. The kit includes a bridge rectifier, resistor, capacitor. Works very well "for me".



As usual, your mileage may vary.

Rich

[Joe Satnik]

Actually,

The zener diode is in the correct orientation, cathode (stripe) up.

It is a shunt regulator with a primary purpose of limiting the voltage across the storage capacitor to 5.1 Volts. 

It also sets the voltage (5.1 V) across the series combo(s) of the LED(s) and its (their) current limiting resistor(s).   

It is better to have a resistor for each LED, as a mismatched LED would "hog" current from the rest of the LEDs.  (It would be brighter, the others would be dimmer.)

Also, Rich, the drawing shows the capacitor as 47,000 uF, while the text shows it as 470,000 uF.  If you could check that for us, please.  Thanks.

Hope this helps.

Sincerely,

Joe Satnik 

[richG]

Yes, I am aware of how the circuit operates. I meant the circuit I have is .047F. sorry for the confusion..
The link I included indicates .47 to 1 F.

You have to understand what the author means by the zener being "backwards".

Also said your mileage may vary..

Here is a description of the circuit from the author.
   1) The bridge rectifier (BR1) takes whatever your layout power is and changes it to

DC with the desired polarity.  The bridge rectifier also prevents the stored charge

from flowing out of the circuit when track power is absent.  I use a 100v, 1a bridge

rectifier.

   2) The R1 resistor slows down the charging of the capacitor and therefore prevents

this circuit from tripping a circuit breaker in DCC.  Use a 1/4 watt, 1000ohm resistor.

A 1000ohm resistor has Brown-Black-Red as its first 3 color bands.  The value of this

resistor should -not- be reduced.  If you increase it's size the circuit will still work - it

will just take longer to fully charge the capacitor.

   3) The capacitor (C1) builds up a charge and then provides the power to keep the

LED(s) lit when track power is temporarily 'gone' such as when the wheels don't

make good contact.  I use a 5.5v, .047F (yes - that is FARAD!) capacitor.

   4) The R2 resistor provides the proper voltage/current to the LED.  If you reduce

the size of this resistor the LED will see more voltage/current and will burn brighter. 

Increase it and the LED will have a dimmer light.  I use a 1/4 watt, 1000ohm resistor

most of the time (see comments elsewhere in this document).

   5) The Zener Diode controls the maximum voltage that the LED and capacitor can

receive - and "protects" them both.  When the track power is removed from the input

side of BR1 then ZD1 "drops out" of the circuit and the capacitor supplies the LED.  I

use a 1N3826 zener diode (5.1v, 1w). 
----------------------------------------------------------------------------------------------------------------------------------------------------------

Some people like to use one resistor for two LEDs. Their choice. I do not.
Again, your mileage may vary as there are different ways to do this. Again, experiment.
Make sure you have a multimeter.

Rich

[bevernie]

 :DGREETINGS!! RICH, do you mean that if I am doing DC, and am running my circuit from a POLARIZED SOURCE, I can dispense with the BRIDGE RECTIFIER part of the circuit??
                                                                                                THANX!!
                                                                                                Ernie

[Joe Satnik]

Bernie,

No, as you will want to run your train in reverse at times (= opposite polarity).

Joe

[bevernie]

 :DGREETINGS!! ???So, Joe, IF I were to operate this circuit WITHOUT the BR, in REVERSE, would that simply mean that I wouldn't have any lights in my cars, or would I blow something up?
  Also, if I wired some cars with opposite polarities, couldn't I have some that light in one direction, and others that light up in the other?(That would be interesting!)
                                                                                              THANX!!
                                                                                              Ernie

[Joe Satnik]

In general, designers don't put LEDs in reverse polarity situations for a long time, as they are not as robust as regular diodes in reverse. 

In situations where reverse voltages are expected, regular diodes are put in series with LEDs for reverse polarity protection.

--l>l----l>l---

reg.     LED

Hope this helps.

Sincerely,

Joe Satnik