Engine will only run backwards

Hi,
I'm trying to bring my old Lionel train set (O gauge) back to working
order. The problem is that the engine (yellow Rio Grande 221 made in
the early 60's) only runs backwards. When I toggle the e-unit to make
it run forwards the motor stops. If I then manually try to move the
motor it seems stuck in a magnetic field.
I notice that the field wiring is double wound with both red and green
magnet wire. I'm guessing that one coil causes the motor to run
forwards, the other causes the motor to run backwards. I'm also
guessing that the forward coil is burned out (although that doesn't
explain the magnetic field mentioned above). Not sure but I don't
think it is the e-unit as it is really just a contact device and it's
pretty obvious that the contacts switch when it toggles.
Could someone familiar with these engines please speculate on a
prognosis? If the coil is burned out it's probably not worth repairing
but my hope is that I'm overlooking a possible simple fix.
Thanks!
Regards,
-- Greg
Reply to
Greg
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The Lionel motors are usiversal wound motors and the reversing is done by swapping the wires for the field winding. I'd findi out what is going on by putting a meter across the field winding and, using DC (the motors work equally well on AC or DC), operate the reverser. You will probably find that the normal direction of movement has no voltage to the field winding.
-- Why do penguins walk so far to get to their nesting grounds?
Reply to
Bob May
I seem to be getting a voltage reading in both directions although in the reverse direction it is slightly less.
-- Greg
Reply to
Greg
The voltage sould be the same in both directions of flow. The voltage level indicates change indicates that one of the contacts on the E-switch is bad.
-- Why do penguins walk so far to get to their nesting grounds?
Reply to
Bob May
I put a jumper across the forward contacts (from common on the e-switch to the motor coil) and it still behaves the same.
-- Greg
Reply to
Greg
Then the problrm isn't electrical. That leaves something in the drivetrain that is causing the slow speed in the forward direction. The resistance to movement of the motor should be the same in both directions and if it isn't, then you need to disassemble the drive to find out why.
-- Why do penguins walk so far to get to their nesting grounds?
Reply to
Bob May
Hello, and I seem to remember visiting an S-gauge website that said a common problem with old AF locos was a preference to run faster in one direction than the other. The problem was attributed to bearing wear in the trucks. It's amazing this stuff works at all after sitting in a hot/cold/humid house attic for 50 years. There once was a company in New Haven, CT that knew how to make robust, long-lived toys. Back in that time when "American quality" meant something other than a punchline. Sincerely,
John Wood (Code 5550) e-mail: snipped-for-privacy@itd.nrl.navy.mil Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337
Reply to
J. B. Wood

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