The addition of traction tires will give the locomotive better grip on the rails. Increased grip on the rails means that the locomotive will pull harder before the wheels start to slip.
The amount of tractive effort required to bring a train up to speed depends on the length of the train, the weight of the cars, the rolling resistance of the cars, the grade of the track, and how quickly you are trying to accelerate the train. Also starting a train that is on a curve is harder than starting a train that is on a straignt section of track.
In other words, a long string of heavy postwar cars will require the locomotive to pull harder to bring them up to speed than a train that consists of just a few modern cars with Fast Angle wheels with low resistance bearings.
Since my knowledge base is on the low side when it comes to determining the physics of toy train motors you'll all have to excuse me if this sounds like a dumb question. But, wouldn't a simple act like adding traction tires reduce the specific tractive effort required during the run-up? Or do I have it backwards?
Becky
Trains, trains, wonderful trains. The more you get, the more you toot!
I'll agree with Bruce. It is my experience that the wheels on the locomotive will spin before the motor will stall.
I think Lionel's postwar equipment was pretty durable. The #210 Texas Special Alco diesel I grew up with is still running. I can remember fanning the direction control on the 1033 transformer to reverse directions with the train running at full speed basically wide open forward, right into wide open reverse.
If you are really curious, you could install an ammeter between your power supply and the track to monitor the current the train draws under various conditions.
I don't think you can hurt your motors under "normal" operating conditions. If the motor is turning and has not been stalled by being restrained by something, it should not draw enough current to overheat. I have regularly pulled more than 20 cars with a 2046 steam engine and a 2333 diesel. Neither engine is working particularly hard with a train like this. The 2046 will spin its wheels if it is given too much power too quickly. Since the 2333 is a dual motor, it can start the train without slipping the wheels.
Bruce Baker
Seems like the peak torque in the motor would happen as you are accelerating the train up to the crusing speed. Once at crusing speed, the torque requirement would fall off, thus the current draw would also fall off.
By this reasoning, accelerating the train slowly would help keep the motor cooler.
An industrial example of this is on the 400 hp motor driving one of the 4000 ton presses we have at work. The motor drives a 60,000 pound flywheel which is connected to the press crank through a clutch to make the press go up and down when the cycle button is pushed. The ammeter on the motor drive indicates a surprisingly low 40 or 50 amps when the flywheel is up to speed and the press is idling. When the press cycles and the flywheel gets slowed down, the ammeter on the motor drive indicates maybe 150 to 200 amps while the motor speeds the flywheel back up between hits on the press.
Thanks again, Bob. I guess I am bringing up this topic because I have always "felt ", whether right or wrong, that it is better for an engine to be cruising around the track at a voltage leading to a comfortable speed (say 30 to 50 smph) than to be at a voltage where it barely makes it through the curves: this regardless of the size of train it is pulling. Again, my basic motivation is to avoid doing things which will harm either the motor or the electronics in the engine.
Heat, or more precisely, temperature, is all that comes to my mind.
Yes, a heavy load or immobilization would certainly increase the current and therefore the possibility of damage. I was responding to the question in the way you proposed it, that is, with the voltage varying but the train remaining the same.
Bob Nelson
Bob,thank you for the input. If a motor is kept clean and well lubricated, is heat the only concern to worry about for abusing the type of electric motors used in our toy trains ? Also, wouldn't a motor overheat even at a relatively low or medium voltage if the engine could not move because of an overlarge drag force?
In an ideal universal motor, torque is proportional to the square of current. The heat produced in the motor windings is also proportional to the square of current. Since more torque is needed at higher speed, the motor produces more heat at higher speed. The more heat, the higher the motor temperature. The problem is in knowing whether the temperature in your locomotive's motor is too high. I would say that, if you can't touch it without burning your fingers, it's too hot.
Can someone tell me if there is more strain on the electric motor of a conventional engine when pulling a long, heavy train at a slow speed (for example, just enough to keep going around the loop) than when pulling the same train at a higher speed (i.e. more voltage)? My goal is to avoid abusing the engine. Thanks for any input.
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