LGB Loco & Powered Tender Speeds

[Madman]

I have an LGB 2017 type loco with powered tender. Both have the older clamshell type gearbox. I noticed when running on my layout that the tender seems to spin it's wheels on slight upgrades.

So on the test stand, the tender starts immediately, while the loco doesn't start until about two volts is reached.

What can be done to get them in line ?

 

[Neil Robinson]

I assume that these early locos will have the motors directly wired to the tracks.
Assuming the motors are generally in good order one solution would be test all your single motor locos to find two motors that run at the same speed. These could be fitted to the problematic loco and the existing motors fitted to less critical single motor locos.
I guess going DCC and tweaking the decoders may work but would involve fitting separate decoders to loco and tender.

 

[idlemarvel]

May be due to the coupling/valve gear on the loco motor block, you could try lubricating that to see if that helps. Is this DC? You could try diodes inline to the tender motor? The LGB ones drop about 0.4v. If it's DCC there was a long discussion recently about the merits of using a decoder for each motor on a thread about the LGB Rugen 0-6-0 tender loco, then you can tune each decoder to get each motor to run in tune with the other.

 

[korm kormsen]

try putting some additional weight into the tender

 

[James Day]

try putting some additional weight into the tender

Dan,

If you think about it, a lot of the Clamshell chassis motors were designed for 14-18v. If your 2017 has older couplings this is almost certain.

As has been said earlier some of those early motors are real greyhounds - my 2050 from 1977/8 is a real whippet!

If the extra weight, or oiling etc doesn't do the trick, try a proven high speed motor in the slower part of the combo just to see what happens.

Janes

 

[Madman]

Thanks all. I run battery power and in the case of this loco/tender combination, a trailing battery car supplies power.

I like the extra weight idea, simply because it's so simply obvious to all but me.....

 

[korm kormsen]

if you use battery, you could install a diode in the line to the faster motor...

 

[Madman]

if you use battery, you could install a diode in the line to the faster motor...

I believe that's what has to be done, Korm. I added weight to the tender and it's wheels spin in vain trying to get the loco to move. Would you show me a diagram and type of diode I need to use ?

 

[korm kormsen]

please, keep your breath untill tomorrow.
(just preparing for a party...)

 

[korm kormsen]

back and not drunk...
diodes: i used these for my tests. but i think, smaller ones would work too.

you can see, that there are two of them in different directions on the same cable.
only one of them works at any given time. the other does not let DC enter.
when you reverse the switch/whatever for backing up the train, the former inactive diode lets pass DC, and the former active does nothing.
the actually active diode "robs" your quicker motor of 0.7 volts.

 

[idlemarvel]

Nice picture Korm, thanks for doing that, it explains it very well.

 

[Madman]

back and not drunk...
diodes: i used these for my tests. but i think, smaller ones would work too.

you can see, that there are two of them in different directions on the same cable.
only one of them works at any given time. the other does not let DC enter.
when you reverse the switch/whatever for backing up the train, the former inactive diode lets pass DC, and the former active does nothing.
the actually active diode "robs" your quicker motor of 0.7 volts.

Thanks Korm !

 

[Madman]

back and not drunk...
diodes: i used these for my tests. but i think, smaller ones would work too.

you can see, that there are two of them in different directions on the same cable.
only one of them works at any given time. the other does not let DC enter.
when you reverse the switch/whatever for backing up the train, the former inactive diode lets pass DC, and the former active does nothing.
the actually active diode "robs" your quicker motor of 0.7 volts.

Dorm, can more than one diode be inserted in series. So if one diode reduces voltage by .7 volts, would a second diode attached to the first one reduce the voltage twice that amount ?

As mentioned, the slower motor doesn't start until about 2 volts is applied.

 

[idlemarvel]

Yes, just make sure they are in the same "direction" as each other.

 

[korm kormsen]

sorry, i didn't mention that.
yes, two strings of three would be what i would try.
in each string al three in the same direction, and the strings in opposing directions

 

[Madman]

sorry, i didn't mention that.
yes, two strings of three would be what i would try.
in each string al three in the same direction, and the strings in opposing directions

What about resistors ? Wouldn't they do the same thing ? Trouble is, determining the right ones

 

[Neil Robinson]

What about resistors ? Wouldn't they do the same thing ? Trouble is, determining the right ones

Diodes are useful in this application as their voltage drop is independent of current. With a resistor the voltage drop varies directly with the current.

 

[korm kormsen]

What about resistors ? Wouldn't they do the same thing ? Trouble is, determining the right ones

i haven't got the slightest idea.

 

[Madman]

I experimented with three diodes I had in my parts drawer. I couldn't read the numbers on them but figured, what the h_ll. With three diodes the voltage drop is 2 volts. That's just about the exact difference in the two different motors at start up. So as soon as the correct diodes arrive I will do the deed.