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Offline macxlii  
#1 Posted : 09 May 2021 15:46:35(UTC)
macxlii

United States   
Joined: 28/05/2012(UTC)
Posts: 5
Location: Fairfax Station, Virginia
The solid state ac speed controllers for the non digital track systems give a voltage range up to 18V with better variability than the old Maerklin autotransformers but they do not give the voltage spike of 24V to activate the reversers on the locos. Is there any ac controller which does have this reversal function? Aternatively, can a 24V spike from a separate transformer be used to do it? Since reversal is done at a standstill, i.e. when the variable voltage from the speed controllers is zero, can I simply connect the output of a 24V transformer fitted with a momentary on/off switch in parallel with the outputs of the lower voltage speed controllers to inject the reversing spike?
Offline DaleSchultz  
#2 Posted : 09 May 2021 17:35:10(UTC)
DaleSchultz

United States   
Joined: 10/02/2006(UTC)
Posts: 3,997
connecting the second power source for a moment might produce a reverse current through the first controller producing more than the input AC voltage on its plug, which is plugged into the AC socket. That could destroy anything else plugged into the AC elsewhere in the house. Good thinking about I think it could be disastrous.

If you could connect the impulse so that it completely disconnects the first power supply first, does the impulse, and then reconnects the first one, I think it would work.
Dale
Intellibox + own software, K-Track
My current layout: https://cabin-layout.mixmox.com
Arrival and Departure signs: https://remotesign.mixmox.com
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Offline scraigen  
#3 Posted : 09 May 2021 19:18:33(UTC)
scraigen


Joined: 29/01/2009(UTC)
Posts: 299
Location: Sheffield,
Use a 24v source with appropriate regulation to drive your solid state circuitry and then have a double throw switch that is momentary in one direction and latching in the other, flip between 18v modulated and 24v reversing.
Must build something
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Offline DTaylor91  
#4 Posted : 09 May 2021 22:57:22(UTC)
DTaylor91


Joined: 31/08/2007(UTC)
Posts: 414
Location: Kennesaw, GA
If your transformer/controller has a separate 18VAC output that isn't variable, perhaps you can add a Voltage Doubler circuit to the output with a momentary switch that temporarily connects the Voltage Doubler output to the track. Circuit in article below, scroll about halfway down to find the Voltage Doubler:

https://www.electronics-...-multiplier-circuit.html

You may need to use a double-pole switch that disconnects the controller from the track while the Voltage Doubler is in use, and vice-versa (At least I'd rig it that way)

[EDIT]: If the resulting 36V spike is too much, you can always attenuate the output of the Voltage Doubler
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Offline JohnjeanB  
#5 Posted : 09 May 2021 23:54:14(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 3,084
Location: Paris, France
Hi
Originally Posted by: macxlii Go to Quoted Post
The solid state ac speed controllers for the non digital track systems give a voltage range up to 18V with better variability than the old Maerklin autotransformers but they do not give the voltage spike of 24V to activate the reversers on the locos. Is there any ac controller which does have this reversal function? Aternatively, can a 24V spike from a separate transformer be used to do it? Since reversal is done at a standstill, i.e. when the variable voltage from the speed controllers is zero, can I simply connect the output of a 24V transformer fitted with a momentary on/off switch in parallel with the outputs of the lower voltage speed controllers to inject the reversing spike?


The only difficulty with generating an AC spike is to insert an idle time (0.5 second) without power before and after the spike. Then it all works great. You need 2 relays to do this (SPDT).
Simply switching from 7 to 14 volts for traction to 24v for direction change usually creates funny reactions and does not work

Of course you know that Märklin produced around 1983 a very interesting item for direction change, pause and smooth acceleration / deceleration: the 6600.
Sadly it was discontinued very rapidly because incompatible with digital models (using voltage hash instead of mure AC)
Cheers
Jean
Offline macxlii  
#6 Posted : 14 May 2021 21:55:20(UTC)
macxlii

United States   
Joined: 28/05/2012(UTC)
Posts: 5
Location: Fairfax Station, Virginia
Originally Posted by: JohnjeanB Go to Quoted Post
Hi
Originally Posted by: macxlii Go to Quoted Post
The solid state ac speed controllers for the non digital track systems give a voltage range up to 18V with better variability than the old Maerklin autotransformers but they do not give the voltage spike of 24V to activate the reversers on the locos. Is there any ac controller which does have this reversal function? Aternatively, can a 24V spike from a separate transformer be used to do it? Since reversal is done at a standstill, i.e. when the variable voltage from the speed controllers is zero, can I simply connect the output of a 24V transformer fitted with a momentary on/off switch in parallel with the outputs of the lower voltage speed controllers to inject the reversing spike?


The only difficulty with generating an AC spike is to insert an idle time (0.5 second) without power before and after the spike. Then it all works great. You need 2 relays to do this (SPDT).
Simply switching from 7 to 14 volts for traction to 24v for direction change usually creates funny reactions and does not work

Of course you know that Märklin produced around 1983 a very interesting item for direction change, pause and smooth acceleration / deceleration: the 6600.
Sadly it was discontinued very rapidly because incompatible with digital models (using voltage hash instead of mure AC)
Cheers
Jean


Thank you JohnJean. I have a 6600 unit which I bought thinking that it had the normal reversing function but it seems that it is only with the shuttle operation that it functions. So, I think that I shall connect a SPDT switch ON-OFF-(MOM ON) to the two ac supplies and then toggle it between the positions.
Offline JohnjeanB  
#7 Posted : 14 May 2021 22:55:43(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 3,084
Location: Paris, France
Hi
Originally Posted by: macxlii Go to Quoted Post
Thank you JohnJean.I have a 6600 unit which I bought thinking that it had the normal reversing function but it seems that it is only with the shuttle operation that it functions.So, I think that I shall connect a SPDT switch ON-OFF-(MOM ON) to the two ac supplies and then toggle it between the positions.

Not sure I understand what you mean.
The 6600 unit can control smooth start and stop as well as pause all this being adjustable.
The unit also allows using its input II to generate an over-voltage for direction change or Telex operation
So you have it all there to organize whatever type of automatic ANALOGUE operation, maneuvers in yard, getting cars or leaving them.

Sadly their death toll came 1 or 2 years later when Digital stated in 1985: not compatible.
Now all this is done using digital and Rocrail (or equivalent) like here on my layout



Just in case you don't have the manual, here it is Marklin 6600 AnleitungR.pdf (2,417kb) downloaded 15 time(s).


Cheers
Jean


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Offline Martti Mäntylä  
#8 Posted : 18 May 2021 09:02:38(UTC)
Martti Mäntylä

Finland   
Joined: 15/11/2018(UTC)
Posts: 397
Location: Uusimaa, Helsinki
Originally Posted by: macxlii Go to Quoted Post

Thank you JohnJean. I have a 6600 unit which I bought thinking that it had the normal reversing function but it seems that it is only with the shuttle operation that it functions. So, I think that I shall connect a SPDT switch ON-OFF-(MOM ON) to the two ac supplies and then toggle it between the positions.

Besides the shuttle operation, you can apply the 6600 unit's reversing function by connecting the input II momentarily to ground potential. I use a K84 to control it digitally.
- Martti M.
Era III analog & digital (Rocrail, CAN Digital Bahn, Gleisbox/MS2, K83/K84), C & M tracks, some Spur 1
Offline mike c  
#9 Posted : 24 May 2021 02:00:32(UTC)
mike c

Canada   
Joined: 28/11/2007(UTC)
Posts: 7,880
Location: Montreal, QC
THE 6600 IS NOT TO BE USED WITH ANY DIGITAL LOCOMOTIVE WITH A MDOERN DECODER. IT WILL CAUSE THE DECODER TO OVERHEAT AND BURN OUT

It's technology worked to allow modellers to have a timed reverse pulse with classic motors/reverse units, so that you could recreate end station direction changes, etc, but as this worked using a chopped AC wave, it will have a nefarious effect on current technology.

Regards

Mike C
Offline macxlii  
#10 Posted : 24 May 2021 02:55:38(UTC)
macxlii

United States   
Joined: 28/05/2012(UTC)
Posts: 5
Location: Fairfax Station, Virginia
Originally Posted by: mike c Go to Quoted Post
THE 6600 IS NOT TO BE USED WITH ANY DIGITAL LOCOMOTIVE WITH A MDOERN DECODER. IT WILL CAUSE THE DECODER TO OVERHEAT AND BURN OUT

It's technology worked to allow modellers to have a timed reverse pulse with classic motors/reverse units, so that you could recreate end station direction changes, etc, but as this worked using a chopped AC wave, it will have a nefarious effect on current technology.

Regards

Mike C


Mike, Thank you for the warning. It is definitely not my problem however as all my track and locomotives are pre digital. Much is from the 1950s -even including 3800/3900 track!) which I bought mid 80s but which has sat in various trunks and boxes since then. My project is to rehabillitate it now although it seems that the onmarch of technology has far outpaced it. The only concession I have had to make so far is the use solid state speed controllers (MRC Tech 4) to replace the original Maerklin autotransformers as the Paxolin boards inside them were, well, very flaky..
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