Loksound V4 cutting Out

[Chinapig]

Hi,
I've an Intermountain cab forward that I'm running on our club layout.  With the help of a powered box car made from a kit by Randgust it's pulling 51 reefers plus a caboose but after a couple of minutes the loco stops working.  The powered box car keeps struggling on.
The loco's lights, bell and whistle still work though.  After a couple of minutes everything returns to normal.
Does anyone know whether this is likely to be the decoder cutting out or the motor somehow refusing to work?  Indeed, can the decoder cut out just on the motor output and not the sound and lights?
If I reduce the number of reefers by a dozen I don't get the problem.
Cheers, Ted

[Steveruger45]

From what you mention it Sounds like decoder overload protection is kicking in.  What current does the problem loco draw in your scenario?

[Chinapig]

Hi Steve,
It'll be a while before I can test a train that long again but it does sound like the decoder overload kicking in.  But would that happen and still leave the sound and lights system working still?
Cheers, Ted

[Steveruger45]

Hi Ted,
I’m not sure on that exactly, but I do believe it would behave as you mentioned if motor was drawing too much current. I say this because similar happened to me once on an old Kato gp50 with a select micro 73800 a long while ago when one of the universals froze up. That little spider thingy in those universals came out and jammed the drive enough for the motor to still spin but the drive train on that end would not turn which overloaded the motor.  I thought I’d damaged the decoder at first but after I fixed the drive train issue, the decoder was ok.  I’m thinking there is some sort of thermal overload device in the decoders motor circuitry that resets when cooled down again.  I’ve never had the same issue again and loco is running great.

[Chinapig]

Hi Steve,
I'm going to have to test the current draw on the loco next we we set the club modules up.  I don't think I've a big problem I'll just have to limit the length of the train somewhat.  Pretty sure it's the motor part of the decoder that's cutting out.
Cheers, Ted

[peteski]

How well is the speed matched between the loco and the power car?  If the loco runs faster than the power car, it will be laboring very hard to pull the power car and the rest of the train behind it.

[jdcolombo]

How well is the speed matched between the loco and the power car?  If the loco runs faster than the power car, it will be laboring very hard to pull the power car and the rest of the train behind it.

Peteski is correct.  The very first thing to check is the speed matching between the power car and the engine.  If they are significantly off, then that could be causing excessive current draw which in turn causes the protection circuits to kick in. 

John C.

[Chinapig]

Just had a look at the speed matching.  It was pretty near perfect but I have adjusted the power car from very slightly slower to very slightly faster.  It may make a difference but it will be at least a month before we have our club layout up again so that I can test a train of this length.
Thanks, Ted

[jdcolombo]

Just had a look at the speed matching.  It was pretty near perfect but I have adjusted the power car from very slightly slower to very slightly faster.  It may make a difference but it will be at least a month before we have our club layout up again so that I can test a train of this length.
Thanks, Ted

Hi Ted.

Remember that the train drag will affect the power car first.  That is, it will have a tendency to run slower even if it is correctly matched to the front engine because it will be bearing most of the initial weight of the train, and with 51 cars + caboose, that's not an insignificant weight amount.  In this case, setting the power car to run a tiny bit faster than the lead loco would be prudent to overcome the train drag.

John C.

[Chinapig]

Just an update on this.
After running the loco for about five minutes I measured the amperage draw which worked out to 0.17 with no load and 0.24 with my finger pressed hard down on the loco nearly stopping it.  During this process it did cut out a couple of times as per the original problem.
I then took the motor out, put a drop of oil on the shafts, removed the wheels, cleaned the brass pickups (what a lot of crud they'd picked up), put it all back together and it's working well now.
I can't help but think it might have been a motor contact just not making it when it warmed up?
Anyway, fingers crossed and thanks for the help.
Cheers, Ted

[nstars]

Reading all the entries, I get the feeling the decoder is overheating. Is there enough space around the decoder for airflow? What is the volume level?

Marc

[Chinapig]

Hmm, I was premature in saying I had it fixed as it cut out again today after pulling a heavy load for quite a while.
Marc, it's an ESU Loksound and I had the sound off.  I'm also tempted to think it's the decoder cutting out but whilst the motor won't turn I can play the whistle and bell.  There's quite a bit of room in the tender so I imagine there's plenty of room for air circulation.
My big question is, can a Loksound decoder cut out on the motor side only totally independently and the sound keep going?

Ted

[RBrodzinsky]

It is sounding more like the motor outputs are solidly connected to the motor tabs.  Can you isolate them and direct wire from the decoder to the motor?  Which model of the V4?  Is the decoder in the tender, and if so, how is power routed to the motor?

[woodone]

What scale are we working on? If N scale and you used the 8 pin socket check that the pins are tight in the socket.

[nstars]

It resembles something we recently had with a Bachmann locomotive. We couldn’t get it to work on DCC (it ran fine on DC) until we found out there was a problem with the motor. One of the poles of the motor shorted which increased the current to a level where in our case the decoder blew. With the Loksound the current protection may have kicked in.

Marc