How to drop power on just one accessory???

[Texas Pete]

KRM

What I did to make this work was this. This CW80 is only used for accessories so I checked to see if the CW80 U terminals were shared and once I saw they were I powered the accessory off of the train side of the transformer and dialed it up to the speed I wanted the accessory to run at. 

A neat feature of the CW-80 is that the accessory output is also adjustable.  Check page 10 of the manual:

http://www.lionel.com/media/servicedocuments/71-4198-250.pdf

This is how I adjust the speed of my accessories, along with the previously mentioned voltage dropping devices so as to allow the use of several different types of accessories on the same transformer.

Pete

[Texas Pete]

lionelsoni

From the one schematic I've seen, it has the same output circuit; so the waveform should be the same.

Thank you.

Pete

[lionelsoni]

From the one schematic I've seen, it has the same output circuit; so the waveform should be the same.

[Texas Pete]

lionelsoni

The reason I asked about your meter is that that kind of traditional meter reads accurately only for sinusoidal voltage.  When used with the kind of waveform that the CW80 puts out, you can get up to about 4 volts error.  I have posted a correction table in the past and will include here later if I can find it.  That doesn't solve your problem; but it will let you make better measurements with the meter you have.

I would be sure to put some load on a CW80, like a lighted car or accessory, when measuring the voltage.  The output circuit has some peculiar behavior when there is no load.

Lionel rheostats are common on Ebay.  You can get bridge-rectifier modules at Radio Shack.  The smallest ones are rated at about 1.4 amperes, which may be too low for your accessory--I'm not familiar with it.  By the way, these rectifier modules are not being used as rectifiers when you do what I described--they are just a handy way of getting the components needed (diodes) in a compact package.

Here is the correction table for the CW80.  It shows that, when your meter reads 13 volts, the actual RMS voltage is 16.6 volts, that is, 3,6 volts higher than the reading.  When your meter shows 10 volts, the actual voltage is 14.1, that is, 4.1 volts higher.

Meter           RMS 
  0             0
  0.5           1.6
  1             2.7
  1.5           3.7
  2             4.6
  2.5           5.4
  3             6.1
  3.5           6.9
  4             7.5
  4.5           8.2
  5             8.8
  5.5           9.5
  6            10
  6.5          10.6
  7            11.2
  7.5          11.7
  8            12.2
  8.5          12.7
  9            13.2
  9.5          13.7
 10            14.1
 10.5          14.6
 11            15
 11.5          15.4
 12            15.8
 12.5          16.2
 13            16.6
 13.5          16.9
 14            17.3
 14.5          17.6
 15            17.9
 15.5          18.2
 16            18.5
 16.5          18.8
 17            19
 17.5          19.3
 18            19.5
 18.5          19.7
 19            19.8
 19.5          19.9
 20            20

Does the accessory output of the CW-80 put out a waveform similar to that of the variable output?  Have you checked it out?

Pete

[KRM]

Guys,

What I did to make this work was this. This CW80 is only used for accessories so I checked to see if the CW80 U terminals were shared and once I saw they were I powered the accessory off of the train side of the transformer and dialed it up to the speed I wanted the accessory to run at. 

 Why Did I not think of this earlier?  

 

[KRM]

Bob,

 First off thanks,

 Yeah I was thinking the same thing that the accessory draws so little current that the drop is not noticeable. I do hear it speed up a tiny bit if I move the rheostat setting to high, but it does not show in the operation of the accessory.

I will do some bench checking and let you know what I find.

 Thanks again,

 Kev

[lionelsoni]

The rheostat is just an adjustable resistor.  The voltage across a resistor is proportional to the current through it; so the voltage drop between your transformer and the accessory is proportional to the current that the accessory draws (as well as proportional to the resistance setting of the rheostat).  I'm not familiar with your accessory; but is it possible that it draws so little current that the drop is not noticeable.

You can test the rheostat by using it to control a train, which is likely to draw more current than the accessory.  If it is able to slow the train down, then the problem is too little current drawn by the accessory and probably not a fault in the rheostat.  Do you have any accessories or lights that you could connect in parallel with the accessory, that you wouldn't mind operating at the lower voltage?

The rheostat is easy to adjust, if it has the necessary resistance range for the load; but the diode schems has the advantage of being insensitive to the load current.

[KRM]

RT,

 Yeah I did not bench test it because it looked good. So I will pull it out from under the table and see if it works on the bench.??

[rtraincollector]

Kev run a line to the rheostat and then to a piece of track and then run a wire from transformer to other rail turn transformer on and turn all the way up slide the piece on the rheostat and see if it dims and brightens a light on a lighted car if not its not working.

[KRM]

lionelsoni

o  Put a Lionel rheostat in series with the transfer station.  Or,

o  Put as many bridge-rectifier modules as needed in series with the transfer station, each wired as follows:  Connect the + and = terminals of the module together.  Wire the ~ terminals into the series string.

 

Bob,

 I installed a Lionel #81 rheostat in the line to the accessory and it made no difference.  Any Ideas??

[KRM]

dbaker48

Kev,

What about picking up another small transformer for that unit.  I find them at train shows for $1 or $2, or even a hobby shop may have some used ones for less than $5.  Then with the use of a power strip power can still be controlled or wired directly.

Just a thought

 Don I could do that. I have several small transformers. but for now I got the Lionel rheostat on the bay for only $.99 and like $2.35 shipping and it can go under the table right by the accessory.

Thanks

[dbaker48]

Kev,

What about picking up another small transformer for that unit.  I find them at train shows for $1 or $2, or even a hobby shop may have some used ones for less than $5.  Then with the use of a power strip power can still be controlled or wired directly.

Just a thought

[Boyd]

You need a flux capacitor.

[lionelsoni]

That's another way to do it; but using the bridge-rectifier modules just gets it done with fewer components.

Note that the instantaneous forward drop of each diode is not the same as the effective drop in the RMS voltage of an AC waveform.  For dropping full-wave sinusoidal AC voltage, you get about .5 volt drop for each pair of diodes.  With the phase-control waveform of the CW80, it could be more, could be less. 

 

[gunrunnerjohn]

To drop about three volts, you could use two strings of silicon diodes.  For one accessory, I suspect just 1N4001 diodes would be plenty.  Five diodes in each of two parallel strings facing in opposite directions.

[rtraincollector]

KRM

rtraincollector

Kevin there are rheostat's all the time on evilbay heres two for $8 http://www.ebay.com/itm/2-LIONEL-CONTROLLING-RHEOSTAT-95-81-0-027-/360483987126?pt=Model_RR_Trains&hash=item53ee851eb6  but there a big list of them if you just search rheostat unter O gauge

 Thanks Bill,

 It would be nice just to dial it down to where it seems fine. I have never seen them before.

There about a year or two befor your time there pre war like around the 1920's - 1930's I think

[KRM]

rtraincollector

Kevin there are rheostat's all the time on evilbay heres two for $8 http://www.ebay.com/itm/2-LIONEL-CONTROLLING-RHEOSTAT-95-81-0-027-/360483987126?pt=Model_RR_Trains&hash=item53ee851eb6  but there a big list of them if you just search rheostat unter O gauge

 Thanks Bill,

 It would be nice just to dial it down to where it seems fine. I have never seen them before.

[KRM]

WOW Bob,

 I had no idea, The factory setting is stated as 12 volts and that is what my reading was so I figuried it was correct. I had no load on it when I tested so I will try again but I already know that somehow I need to cut this one accessory back.

 Thanks,

 Kev

[lionelsoni]

The reason I asked about your meter is that that kind of traditional meter reads accurately only for sinusoidal voltage.  When used with the kind of waveform that the CW80 puts out, you can get up to about 4 volts error.  I have posted a correction table in the past and will include here later if I can find it.  That doesn't solve your problem; but it will let you make better measurements with the meter you have.

I would be sure to put some load on a CW80, like a lighted car or accessory, when measuring the voltage.  The output circuit has some peculiar behavior when there is no load.

Lionel rheostats are common on Ebay.  You can get bridge-rectifier modules at Radio Shack.  The smallest ones are rated at about 1.4 amperes, which may be too low for your accessory--I'm not familiar with it.  By the way, these rectifier modules are not being used as rectifiers when you do what I described--they are just a handy way of getting the components needed (diodes) in a compact package.

Here is the correction table for the CW80.  It shows that, when your meter reads 13 volts, the actual RMS voltage is 16.6 volts, that is, 3,6 volts higher than the reading.  When your meter shows 10 volts, the actual voltage is 14.1, that is, 4.1 volts higher.

Meter           RMS 
  0             0
  0.5           1.6
  1             2.7
  1.5           3.7
  2             4.6
  2.5           5.4
  3             6.1
  3.5           6.9
  4             7.5
  4.5           8.2
  5             8.8
  5.5           9.5
  6            10
  6.5          10.6
  7            11.2
  7.5          11.7
  8            12.2
  8.5          12.7
  9            13.2
  9.5          13.7
 10            14.1
 10.5          14.6
 11            15
 11.5          15.4
 12            15.8
 12.5          16.2
 13            16.6
 13.5          16.9
 14            17.3
 14.5          17.6
 15            17.9
 15.5          18.2
 16            18.5
 16.5          18.8
 17            19
 17.5          19.3
 18            19.5
 18.5          19.7
 19            19.8
 19.5          19.9
 20            20

[rtraincollector]

Kevin there are rheostat's all the time on evilbay heres two for $8 http://www.ebay.com/itm/2-LIONEL-CONTROLLING-RHEOSTAT-95-81-0-027-/360483987126?pt=Model_RR_Trains&hash=item53ee851eb6  but there a big list of them if you just search rheostat unter O gauge

[KRM]

Bob I used a voltmeter much like the one you suggested in another post today..

I un-hook the transformer from the rest of the accessories and read off the terminals on the back and set it like it tells you to in the manual. Most of the accessories call for 12 to 14 volts so i just thought 13 was a good place to be.

Do you have a part number and a place where I could get the rheostat or bridge-rectifiers?

Thanks for your help again!!

[lionelsoni]

o  Put a Lionel rheostat in series with the transfer station.  Or,

o  Put as many bridge-rectifier modules as needed in series with the transfer station, each wired as follows:  Connect the + and = terminals of the module together.  Wire the ~ terminals into the series string.

I am curious to know how you know that your transformer is set to 13 volts.  If you used a voltmeter, what kind?

[KRM]

I have a CW80 I use to power some of my accessories and it is set to 13 volts. I have a Lionel Transfer Station where this guy goes back and forth with a pallet but at 13 volts he flies back and forth. If I set the voltage lower, like 10 volts it still dose not slow that much but the other accessories need more power to work right.  How can I slow down just this one accessory and not drop the 13 volt setting for the others?

Tks,

 Kev