LGB 25852 sound mallet drawing 4 amps

[stevedenver]

need some ideas on how to interpret this amperage draw.
1 I run analog-running a bridgewerks 10 amp, very clean DC
2 track is clean as are loco wheels, plunger brushes, inside of wheel, as well as tyres
3 both motor units are running same speed
4 drops to 2 amps running in reverse
5 loco has had less than three-five hours use since new
6 other than amperage, all seems normal, including speed, no funny smells, etc
7 other locos run at normal amperage draw-ie a non sound mallet at about 1, moguls ditto, stainz .5, etc
8 engine runs smoothly and slowly without hesitation or stalling, up grade, down grade etc

took it apart and did not see any gunk or the like which would have entered the grear boxes, nor did I see anything goopy when I opened the gear boxes, but did not remove the axels etc to view worms

I don't know if this a dirty commutator rings (on both motors??), some sort of resistance when on the tracks, ie some interference with pick up, or what.

 

[HBBahn]

A couple of quick things:

- check each motor individually by putting the loco on blocks & applying power through crocodile clips onto the skates

- if there's a significant difference between forward and reverse, it could be that something is binding. Check the quartering on all axles.

 

[Neil Robinson]

drops to 2 amps running in reverse

I suggest you take a close look at the possible causes of this first.

A few suggestions

Turn the loco round and retest, just in case the ammeter is giving a misleading reading with reversed polarity. Unlikely but simple to check.

Remove all motion rods from both bogies and re rest.

Disconnect one bogie, run the loco on in both directions rollers. Repeat with power to other bogie only.

 

[PhilP]

Check continuity down each side of the loco..
I have found with some only one wheel, or skate, actually picking-up and passing power.

Use continuity tester to start, and with one lead on first wheel, work your way down that side of the loco checking wheels, and skates, for continuity.
Clean the back faces of wheels where plungers rub.
Check for contamination of the plunger casings, and the wires inside the motor-blocks, with oil / grease.

I have had to 'de-grease' these areas, and tweak the bus-wires in the blocks on a number of loco's..

Quartering (as stated above). Binding of motion. Wear on one, or more, idlers in the motor-blocks.

 

[minimans]

I'll bet it's the front motor? if the smoke stack is leaking fluid or it's been overfilled it drips down onto the motor causing this very problem, check the front motor draw............

 

[stevedenver]

and the winner is..................PhilP!!!!!! :-*

thanks to all

it was indeed the plungers on one side -either dirt or inadequate pressure, but its sorted -I hope
running at 1 amp @10-12 volts, both directions
amps still rise a bit when voltage increased-

 

[PhilP]

Whenever I am given a loco to do any work on (service, or decoder fit) I always run it analogue, in both directions, first to get a feel for any problems which have not been disclosed.. My bench supply also has an ammeter, so I get an idea of current consumption as well. - Good indication of any problems in the drive-chain, of current collection.
Glad to have been of help.
Enjoy!!