Large Scale Central

Odd motor behavior

General Discussion
#1

I have an old LGB 2017. Just the other day it started acting strangley–it would run extremely well backwards, but haltingly and weakly running forward. I put it on the bench and took it apart, and the motor runs more slowly and more weakly in forward. It spins in both directions, but with the polarity set to “forward” it’s very easy to stop the spinning with my fingers. With the polarity set in reverse, it’s much much harder. Also it sounds different in forward, lower pitched

Now why would that be, and how can I fix it?

#2

A couple of questions to help you troubleshoot the problem …

What is in the circuit? Are there any LGB electronics and/or switches involved between the motor and the power source? Is the voltage measured at the motor terminals the same in both directions? Could just be a faulty polarity switch. Since you most always run in the forward direction, something in the forward circuit has gone south.

#3

Mike,

Everytime I take one of my locomotives to the repair shop, the problem seems to go away. You might try that…:stuck_out_tongue:

I had a horse like that one. Everytime I took him to the vet, he got well…

#4

I agree with Del. First reverse the power leads to the engine so your power supply is set to reverse for the motor to go forward, p.s forward for motor to go reverse. See if it improves forward performance of engine.

Sincerely,

Joe Satnik

#5

I took the motor out and replaced it, but the problem continues. I’m pretty sure I have a short in the power pickup somewhere, but I can’t understand a short that only works when the polarity is set to “forward.”

I’m going to strip it down again and make sure of all the connections

#6

it isn’t a short. It is a poor connection in the reverse switch or wiring. Power pickups are fine if it works in reverse.

#7

and sometimes (experience), simply loose motor contact to the vertical bars.
But, you said you took it apart and it did the same thing.
Did you take the motor out of the chassis and test it?

Maybe your power supply is fratzed in one direction?

#8

Thank you all very much

This loco was running via an aristo 75 mhz onboard reciever. This summer I gutted the loco, took all the original LGB wiring out, and wired up the aristo reciever. I pulled the LGB 3 wires dealio and replace dit with two motor leads soldered to the motor, and two track power rleads soldered to the brass contact point son top of the brick. It ran fine for a couple months, then suddenly a couple days ago started this odd behavior

I took the motor out and tested it by itself on the bench. It seemed to run unevenly, So I thought ok, maybe it was damaged by running on an Aristo PWM throttle." So I happened to have a brand new replacement motor. I dropped that in, reassembled the loco, and it did the same thing. Same thing on my test bench as it did on my track.

I rewired the front headlight so it was powered directly from the track, with a bridge rectifier so that it was on regardless of track polarity. AHA! Power pickup is intermitent. But only in forward. That’s the part that seems puzzling to me. It should be intermitent in both directions, no?

Tonight I’ll tear it down again and check the power contacts inside the LGB brick. Resolder the connections. I can only assume there is some short in the brick which opens up when the brick torques a little in forward

#9

Even get to that point where you’re so determined to figure it out you lose sight of everything else?

Anyway I nailed it–the plunger pistons on one side were not extending all the way. When the brick moved backwards, it shifted to one side, enough to make contact. When it moved forward, it shifted away

Seems like it’s working so far.

#10

That’s a problem with those pickups.
Oil and dirt, even dust, and they’ll lock.
I keep lighter fluid and q-tips on the bench for that and other cleaning needs.