Wednesday, June 12, 2013

Motors and Gear Wheels

LGB locomotives are getting older. After all, LGB driving stock has been around for more than 45 years now. Most of the locomotives were made to run for about 800-1200 hours which would loosely translate into 5-10 years of operation. NOW- we all know by now that a German made LGB loco runs much longer - 'way much longer' in Generation X speak... But there comes a time after maybe 20 or so years.... that the material will run its course. And today's topic is about the relation between the Buehler motors and the gear wheels.

Motors: There are 2 types of Buehler motors. The older one was utilized for the very first LGB engines starting from 1968. It was custom-made for Lehmann by Buehler back then. In the early 90's Buehler changed the design of the long and short shaft motors to achieve better cost-profit margins. Some of those 2nd generation motors might die earlier than the first generation. But what leads to the demise of those motors other than old age? And why do the gear wheels play such an important role in this?

 'dead' Buehler motors
Motor Demise: One of the coils fail (mechanical overload, bad soldering spot or else), thus the motor runs rough. With that it puts an excessive mechanical strain on the gear wheel. The collector then gets clogged up with carbon dust shorting the other collector segments. This results in a large heat production inside the motor which travels to the gear wheel via the axle and the worm gear. Now the worm gear eats itself into the plastic gear wheel. Result: the loco stops running. And you might think it is a faulty gear wheel because that is what you see first when you check.
Mechanical overload :  too many additional lead weights in the loco (thinking to improve loco traction...), loco is running unattended, derails and gets stuck still running, human weight from above ( a 2-year-old lies on top of the loco trying to ride it...). If the loco is blocked suddenly then the plastic of the gear wheel gets damaged by the worm gear because the motor keeps running. The damaged plastic wheel results in a rough driving characteristic and a higher electrical load to the motor which eventually kills the motor.
Small selection of LGB gear wheels
Gear Wheel: There are about 15 different gear wheels. Different LGB locos use different gear wheels and one LGB loco may have more than one type of gear wheel. All LGB gear wheels are made of plastic and were manufactured in Germany. Three colors are prevalent: white, grey and black. The color does not define the type needed.


Gear Wheel Demise: In case the loco runs 24-7 or similar - like in doctor's offices, in children's hospitals, in public parks or exhibitions - the axles work themselves into the motor block body thus widening the bearing of the axle (See also our blog about Operating 24/7 in Feb/2013). The axle starts to wobble thus changing the precision position of the gear wheel. The plastic gear wheel wears off , and the worm gear cannot grab it as before thus either the loco just stops or the motor gets too much load resulting in a slow demise.
In case the gear wheel is connected to the intermediate gear wheel this intermediate wheel then gets damaged as a result of the wobbling and the motor gets damaged in the long run as well. If this happens in a steam loco the wheels that are interconnected with a connecting rod loose their synchronization and start binding. The connecting rods get damaged and the motor will get a devastating overload.

What to do: Call Klaus ( at 770-886-6670) and discuss your loco operation mode with him to determine what parts you need and how to prevent similar damage in the future. Klaus has Buehler motors and all gear wheels in stock to keep your LGB trains running.