That the circus engine is definitely at fault, it's pulling 3 times more than the other 2, so it seems that something is causing the extra load. You've checked that there's no binding on the wheels, and rods, the gears are greased and in good condition, so it's probably the motor on its way out
Circus Engine
- Thread starter zman50
- Start date
Neil Robinson
Registered
Agreed. However the motor may not be on the way out, its possible that the motor's commutator has excess carbon deposit. Either way the loco will need some dismantling to remove the motor so I suggest you clean and test the motor on its own. On its own the motor should show about 0.1 to 0.15 amps on your meter
stevedenver
Registered
New motor, likely.
before they die, they begin to draw more juice.
assuming the motor is not the old replaceable brush type,
something i have done to remove excess commutator gunk is to submerge the motor in 91% denatured alcohol, (meths) remove, run, repeat, . Shake out excess, use small shot of electronic contact cleaner. See if things improve.
also things may improve by cleaning , backs of wheels, tread area, skates, contact brush plungers.
fwiw, those old starter controlers can run 2 locos, as you know, but……eventually the combined load, w/o grade or cars, overheats the controller.
my other suggestion, get a 5 amp power source, minimal. It makes a big difference in performance.
before they die, they begin to draw more juice.
assuming the motor is not the old replaceable brush type,
something i have done to remove excess commutator gunk is to submerge the motor in 91% denatured alcohol, (meths) remove, run, repeat, . Shake out excess, use small shot of electronic contact cleaner. See if things improve.
also things may improve by cleaning , backs of wheels, tread area, skates, contact brush plungers.
fwiw, those old starter controlers can run 2 locos, as you know, but……eventually the combined load, w/o grade or cars, overheats the controller.
my other suggestion, get a 5 amp power source, minimal. It makes a big difference in performance.
Last edited:
Fred2179G
Registered
Great job! Well, those are all ampere readings, so 0.33 is about 1/3rd of an amp. 0.98 is almost 1 amp. Your power supply is rated at 0.33A, or 1/3rd of an amp, like your 2 non-problem locos.
You can't get 0.98A out of a 0.33A power supply, so the loco goes really slow as it isn't getting enough amps. Note that the 0.33A power supply probably has a margin of oversupply, so it can probably produce 0.9A which will drive the same 2 non-problem locos or the one circus loco. But it clearly won't drive the circus loco and another at the same time as that would need 0.98A+0.33A= 1.31amps.
If the locos are all the identical type, even if one is painted Circus, then there is something wrong with it. But, as someone commented, there may be other factors - incandescent lights, smoke unit failure, or similar.
I am not an LGB loco expert so I can't tell you why it needs 3 times as much power as the other 2. I suggest you consult an expert LGB loco repair shop.
Well when I cleaned the gears of the old grease one of the wheels may have lifted up and moved a cog, but I am not sure how to check or adjust for that. Thanks
PhilP
G Scale, 7/8th's, Electronics
If you look side-on, then the wheels need to be in the same positions..
They are never 100% perfect, but even one tooth out, is enough to cause binding.
See the vertical line, moulded into the wheels?
Both are vertical, so all is good. - With the loco upside down, and the bottom of the block removed, you can gently lift one axle, and turn it slightly. Drop it back into the block, and see if you have gone the right way.
PhilP
They are never 100% perfect, but even one tooth out, is enough to cause binding.
See the vertical line, moulded into the wheels?
Both are vertical, so all is good. - With the loco upside down, and the bottom of the block removed, you can gently lift one axle, and turn it slightly. Drop it back into the block, and see if you have gone the right way.
PhilP
Thanks My next thing to check is that the wheels are alligned, I may have lifted them up a bit when cleaning the old grease off. After that I will probably pull motor out and clean like you suggested.
Thanks Phil I will check that out, did not realize it was that simple
Thanks for that explanation of the amperes.
Greg Elmassian
Guest
I agree, drawing 3x current, either brushes damaged/worn or motor windings shorted or both...
Greg
Greg
Well nows the time to get stuck in, you're not likely to make things worse!
Greg Elmassian
Guest
you can measure the current again, but it's bad most likely. is there any binding the the rest of the rotating parts with the motor out?
All pieces are apart, wheels, side rods, so to late to check for that. Would like a diagram of how to power, and check the motor for amps used, and what that reading should be. Thanks
Greg Elmassian
Guest
OK, so most likely you have bad brushes or a shorted winding.
use the low ohms scale on your meter and connect to the brushes. The motor probably has 5 commutator segments.... so SLOWLY turn the motor to a position and observe the resistance (again be on the ohms scale where you can read just a few ohms, under 100)... then rotate the motor a few more degrees and stop and see if you get a different reading.
What you are looking for is a position where the ohms are WAY lower or WAY higher.
If the loco ran smoothly, there probably is not a drive train issue (normally you might have it "catch" or slow down at the same rotational position of the driver, for example.
Hope this helps. (what happens is that the insulation in the windings in the motor fails and provides a partial short, the motor will still run but draw a lot more current).
Another possibility would be brushes very worn or damaged, but normally this draws LESS current, which is not your problem.
Greg
use the low ohms scale on your meter and connect to the brushes. The motor probably has 5 commutator segments.... so SLOWLY turn the motor to a position and observe the resistance (again be on the ohms scale where you can read just a few ohms, under 100)... then rotate the motor a few more degrees and stop and see if you get a different reading.
What you are looking for is a position where the ohms are WAY lower or WAY higher.
If the loco ran smoothly, there probably is not a drive train issue (normally you might have it "catch" or slow down at the same rotational position of the driver, for example.
Hope this helps. (what happens is that the insulation in the windings in the motor fails and provides a partial short, the motor will still run but draw a lot more current).
Another possibility would be brushes very worn or damaged, but normally this draws LESS current, which is not your problem.
Greg
My meter may not be working properly, as when I set the ohms to 200 which is the lowest and touch probes together nothing happens. Same when I touched the two motor contacts. Has anyone opened up a motor like this to check inside? On ebay new ones go for 70-90 US, thats to much to put into this engine. I could see around 30 US. Maybe someone could suggest a more reasonable vendor. Thanks
No I moved it.