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 Posted - May 31 2020 : 11:55:25 PM
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So, I was going to shoot a video, tried another 1/2 amp transformer, the bus barely moved, and alarmingly
put out a puff of smoke.
Fearing the worst, I put in a 1 amp MRC unit and the bus merrily came to life and performed well through
all speed ranges. After a few minutes I shut it down and assembled the necessary stuff to shoot a video.
Tried to start the bus and it was now dead as a door nail.
Took the shell off, got a few brief hums and flickers, the motor, at one point, ran a few seconds then
quit again. The motor turns freely, but even applying the juice directly to the contacts, nada. Not even
the lights come on. Sometimes the overload indicator comes on the transformer, so presumably there
is some kind of short.
All the wiring looks intact, no loose leads, nothing touching something else. I am baffled. Tried blowing
the motor out with computer keyboard cleaner, no dice.
Totally stumped. Is it possible that it sucked up a small bit of metal causing some internal short?
Disassembling the motor looks like a long shot as it is riveted.
I tried it yet again, this time had flames and smoke. Not a good sign. Can't quite tell where the action
is, but is looks like some sort of assemblage on the right side of the motor, to where I would guess some
kind of brush assembly exists.
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Posted - June 01 2020 : 09:53:03 AM
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| I absolutely hate when that happens. Everything is fine, and then without changing anything, now there is a problem. Sorry to hear. Sounds like the transformer may have done something to it. But I'm no electrical expert..
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Posted - June 01 2020 : 12:49:48 PM
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Shame that the bus unit stopped after a few minutes of operation.
Maybe the unit is from Europe and uses a different electrical output.
Just guessing.
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Posted - June 01 2020 : 7:10:47 PM
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It could be something wrong with the brushes. For example, they may be worn out.
It also sounds like the windings on the armature or the field coil could be bad. If the lacquer on a winding melted, it could make a mini short removing some number of windings from operation, thus lowering the resistance and raising the current draw. It struck me as odd, from the beginning, that such a small motor should draw more than half an amp.
Carpe Manana!
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Posted - June 01 2020 : 8:31:43 PM
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That is useful info, scss. In point of fact, the owner's manual said that
the motor "draws very little current." In fact, it would scarcely budge
with a half amp toy transformer, and would only dig in with the 1 amp
MRC unit.
The only thing that changed before it quit was going from the toy transformer to a 1 amp transformer.
The other thing is, WKS, it briefly crossed my mind that this could
be a result of European type voltage, but again, this unit was
made for the US market, an additionally it was designed to run
off either AC or DC due to some curious sort of construction of
the motor. I never knew there was such a thing as an AC/DC
motor, I assumed it was one or the other.
I will be looking for a replacement, they are out there, just
have to pay up for it.
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Posted - June 01 2020 : 11:17:22 PM
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quote:It was designed to run off either AC or DC due to some curious sort of construction of the motor. I never knew there was such a thing as an AC/DC motor, I assumed it was one or the other.
Originally posted by Chops124Â -Â June 01 2020Â :Â 8:31:43 PM
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In one of the pictures you posted, the motor appeared to have a field coil rather than a permanent magnet. That's normal for AC trains, like the Lionel O gauge trains. It works with AC because the field coil, and therefore the field, alternates the same as the current in the armature.
It also happens that if you give that same sort of motor DC, the field coil creates the same sort of field as a permanent magnet (it doesn't alternate), so the direct current in the armature works just the same as the direct current in a permanent magnet motor. The one difference is that the motor will only run forward, because if you reverse the DC, you reverse it in both the field coil and the armature, so the motor always turns the same way with AC or with DC flowing either way.
Carpe Manana!
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Posted - June 01 2020 : 11:45:30 PM
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Yes, that is right, it would only function in one direction regardless
of which way the reversing switch was turned.
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Posted - June 02 2020 : 08:23:04 AM
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| First, I would figure out which transformer is the correct one to use. If that played any factor in wrecking the bus, another may break.
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