My 432 DC armature gets hot. It measures 2.2 ohms. Running it on a test stand with no lights or smoked attached it is drawing 3.3 amps. This seems awfully high for running with no load. Does anyone know if this is out of range?
Hi, are you sure your posting the right number ? An American Flyer 432 is a pre war engine that not only didn't have a smoke unit, but would not have been DC.
That is too high, with no load it should be 1A or less. What year is it, the 1950 DC motors are substantially different than the 1947 through 1949 motors.
If there is no date stamp under the boiler shell, the easiest way to tell is look for an oil slinger on the armature shaft. 1950 DC motors have them, 1947 through 1949 do not.
Having worked on a number of HO scale locomotives (including some Gilbert items) that have DC permenant magnet motors, I would advise that if your motor is overheating, and has reduced torque, it's extremely likely that the motor's field magnet has lost a significant portion of its strength.
Dissasembling DC motors that make use of Alnico field magnets will permenantly weaken the strength of the magnet, often to an extent that it will cause problems for the operability of the equipment. There is solutions to the problem- either replace the alnico magnet with a strong neodymium magnet, or find/make a magnetizer that is strong enough to re-charge the field magnet.I don't think any Gilbert S gauge locomotive should draw that many amps under no load, something definitely isn't right. My money is on the field magnet being weak.
-Ellie
There is no date. But I know it is the 47-49 model. The wire on the armature is black and some of it is loose. Although the ohm measurement is within range I am thinking that the armature needs to be rewound.
The armature used in the 1947 through 1949 motors should measure 2.7 to 2.9 ohms between any two commutator segments.
your Armature is dying. You need to replace it or get it re-wound. Also, and this is rare, the Alnico magnet in the feild maybe weak after 70 yrs and needs replacing also.
I am sending to Bob Hannon to have it rewound.
In my opinion you have picked the right person for the rewind!
Bob also makes a limited DC pullmor armature that copies the ones Gilbert made for their display showroom layouts . I have 2 and use them in 332's. they work great.
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