# LGB powered tender question



## lownote (Jan 3, 2008)

I have an old LGB 0-4-0 steamer (2017 I think) which I've repainted and modified a bit. It pulls a string of hartland mini cars which is very popular with the kids who visit. I wanted to see if I could get it to pull better so after reading George Schreyer's tips page I went and bought an LGB powered tender on ebay. I've got it hooked up so it's both powering (I use track power) and being controlled by an aristo 75 mhz onboard unit. 


Is there a way to sync the speds of the two? It does pull better with the owered tender, but the loco is faster than the tender. I'd like to try to match them up a little better. 

Any ideas on how to match them up? Maybe drop the voltage going to the loco uisng a resistor? I'm no EE, I blunder along.


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## Treeman (Jan 6, 2008)

If they are close to the same speed just hook them together and let them run.


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## Dan Pierce (Jan 2, 2008)

Get the tender instructions as there is a set of switches inside for delay. Make sure these are set to the default (fast setting). 

Other than that, I would add back to back diodes to the faster unit's motor to slow it down. 

Add a switch to short the diodes when not using the second unit.


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## lownote (Jan 3, 2008)

I'l look for the tender instructions--I had it comepletely apart to wire it for the TE receiver and didn't see any way to adjust the speed--there were no switches.

The diodes would drop the voltage? When you say back to back just two diodes in series? I suppose I could put them on the motor leads from the TE unit?


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## markoles (Jan 2, 2008)

Mike,

Do you have any way of telling the vintage? Does it have two round holes off to one side on the loco side? Does the loco have a matching pair of holes? The 2017D I have is a 1986 vintage unit and came with a two conductor cable that went between engine and tender. Those were quickly lost, and my tender runs better than the loco, so it often is slamming up against the engine. I haven't really felt a need to hook them together electrically, but perhaps it would improve the running performance if I did.


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## Snoq Pass (Jan 2, 2008)

Posted By Dan Pierce, "Other than that, I would add back to back diodes to the faster unit's motor to slow it down." 

Wouldn't a resistor be better, since a diode prevents the flow of electricity from one direction, but allows electricity flow from the other. Where as a resistor just restricts the flow of electricity.


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## dbodnar (Jan 2, 2008)

Back-to-back diodes means that you wire two diodes in parallel, one facing one way and the other facing the other way - this drops the voltage about 0.7 volts - add additional pairs of diodes to drop it more. The additional diodes go in series with the first set -


For more details see this article: Using Diodes to Control Train Speed 


It works very well and is easier to adjust than resistors

dave


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## lownote (Jan 3, 2008)

Thanks Dave--I'l read that asap. 

Mark I don't get these as a set--I had the 2017 and then bought a powered tender on ebay. The tendr has the two hole son both ends for power, although now they do nothing because i rewired the whole thing


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## Greg Elmassian (Jan 3, 2008)

To reinforce Dave's comment, using diodes gives you a fixed voltage drop per diode, and no heat sinking required. Using resistors will often generate more heat, and the amount of voltage dropped by the resistor varies with the load, so, in my opinion, motor/speed control is not as good. 

Regards, Greg


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## Snoq Pass (Jan 2, 2008)

Ah, I get the diode thing now. Thanks


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## Road Foreman (Jan 2, 2008)

lownote, 

The loco should be a little faster so that the tender is not trying to push.. You can also hook the track power of the 2 together so that they are both getting the same voltage all the time.. 

BulletBob


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## lownote (Jan 3, 2008)

Bob:

These are already wired together--they are both running on track power using an aristo 75 mhz onboard remote decoder. the track power leads form both the loco and the tendr go to the track power pins on the decoder, and the motor leads for both are going frm the motor leads on the decoder. The track is constantly powered at 20 volts. I can see your point about the loco pulling




I may try the diodes, but I'm not eager to take the whole thing apart again, and then try to figure out which direction to orent the diodes on each motor lead to the loco!


Thanks again everyone for the help


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## jnic (Jan 2, 2008)

I bought a loco and powered tender - separately - on ebay. Both have the two conductor cable holes and the cord was included with the tender. I put both on the track unconnected and one out ran the other (don't recall which was faster). I connected them with the connector cable, left them uncoupled and observed that they run at identical speed. I use track power with an Aristo 10amp transformer and a radio controlled onboard unit just like you.


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## Guest (Oct 23, 2008)

you should cross jump track power. More wheels gives more reliable power pickup.

if the motors don't run at the same speed, put pair of diodes (3 amp) in anti-parallel in series with the faster one's motor. If that is not enough, use two sets. It won't matter which way they go in because one of them is always pointed in the right direction. They can go in either lead to the faster motor.


If one set of diodes is too much, move to small resistors. Those motors probably run light at an amp or so, so 1 ohm will result in 1 volt of drop, more than one pair of diodes. You'll need some small values of resistors.

- gws


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## Greg Elmassian (Jan 3, 2008)

Don't worry too much about getting the locos to match speed exactly, when under load, both will contribute to pulling power and there will little bucking. 

It's the worst when you run the 2 locos by themselves. 

Regards, Greg


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## Dan Pierce (Jan 2, 2008)

I found that an easy way to add 2 diodes in each direction was to use a full wave rectifier bridge. Short the plus and minus together and add the AC leads in series with the motor. 

Much easier than soldering 4 diodes.


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## lownote (Jan 3, 2008)

I ended up putting four 4-amp diodes in anti parralel on one leg of the loco motor lead. Worked like a charm. The two units are now very closely matched in speed. Thanks everyone


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