Monthly Archives: December 2014

12-31-14 lubrication

The last day of 2014. Happy new year.

It seems like things always come in groups. A few days ago I had a client asking about improving a TYCO engine. As I found, it’s main problem was to much of the wrong type of lubrication. Basically the motor brushes and other critical electrical contacts were literally dripping in a low viscosity oil. (Swimming may be a more appropriate description.)
It was a wonder that the engine would run at all.

This week a client sent me an early Athearn RTR engine. The main problem description is that it runs very slowly.

Trying to run a few initial tests showed that it would not run without some coaxing at all power settings. The condition would not allow a successful set of as received tests.

A visual examination during the subsequent tear down revealed a similar condition as was found on the TYCO unit. The square bearings on the axles were dripping with a low viscosity oil. As was every movable surface between the truck and chassis. The unit has the conventional blue box metal strip connecting the truck towers to the top of the motor. These surfaces had the oil film between them as well. Finally, the motor had the oil running on the communicator. The brushes and springs were also saturated with the oily substance. Needless to say the oil is the likely source of the problem.

After a through cleaning a consist an running condition was achieved at voltages above 8 volts. This cleaning included:

1- all chassis surfaces
2- all truck parts including wheels bearing and axle assemblies.
3- the metal strap
4- external motor surfaces
5- motor brush cavities
6- the motor shaft on each end were mopped with a tissue until the substance was no longer visible.
7- the communicator was cleaned repeatedly until the substance no longer ran.

The brushes and springs were replaced with a fresh set.

Even with this cleaning, the minimum run voltage was 8 volts. The speed at 12 volts measured 40 SMPH. The 16 volt speed was a lack luster 75 SMPH. The current levels are only .28 amps at the 16 volt setting. These speed values are considerably lower than most systems of this type from Athearn. The running was still erratic enough that draw bar measurements were not attempted.

It is apparent that the motor has been compromised by the oil. Based on the other findings, it is likely present between the magnets and the windings.

At this point, it was decided to replace the motor with a known healthy unit. With everything else the same, the unit indicates a starting voltage under 2 volts and a 16 volt SMPH over 110. These are both consistent with this type Athearn unit.

The details of this test work will be discussed in other posts. It is clear that this engine has suffered from over lubrication with the wrong type material. Fortunately, the plastic has not been compromised.

This unit and the TYCO engine before point out the need to use the proper amounts of the right kind of lubricating material. Gears require a good gear grease. Non-electrical bearing surfaces need a small amount of oil with sufficient viscosity to stay where it intended.

Electrical bearing surfaces require a conducting lubricant. Generally it is better to leave these surfaces dry than to use the wrong lubricant.

The brushes and springs do no need to be lubricated.

In all cases, the material tends to spread on its own. So a little is all that is required.
Truly less is more.