Postwar motor and running question

[msacco]

Excuse my ignorance here, but i'm running my postwar engines more than ever now after really just taking them out once or twice a year.
I know a.c. motors run warm/hot after a while. Should postwar engines be given a rest period to cool off and if so, how long should they run continuously at a slow speed before you rest them?
Also, since they do get warm, how does this effect the running. I seem to find that after they've been running for a while they require slightly more voltage to keep the same intial running speed. Is this normal for a.c. motors?

thanks in advance.

mike Sacco

[Sturgeon-Phish]

My American Flyer engines will run warmer after continous operation. The normal heat increase is a result of winding resistance and other inefficiencies in the generation and induction of the magnetic flux used to produce torque at the motor shaft. The general rule of thumb for motor life expectancy is every 10 degrees in C rise in motor temp results in a 50% decrease in motor life. Significant heat increase is a bad thing. Keep them lubed and wheels free rolling including rolling stock. At train shows I rotate engines after about 2 hours of operation. An ammeter to monitor current draw is an excellent and essiential work bench tool.
Jim

[3railguy]

Run them hot. The aroma is priceless.

[andregg1]

QUOTE: Originally posted by 3railguy

Run them hot. The aroma is priceless.

Agree with you...I thing .we will die before any postwar motor.....
Andre.

[eZAK]

15 min.of rest in each 2 hrs. of run time.

[Anonymous]

Small motors do tend to heat up after running for some time but thet should not get too hot to handle. Some of the old Flyer engins did have a tendency to get hot enought to melt the plastic bodies of some engins but that was unusual. The main culprit is friction due to a lack of proper lubrication. Running a close second however is a dirty commutator, brushes, or brush plate ( holder). Ihave seen dirt in this area burn up a motor faster than anything.