The open framed motor for the majority of Brass Steam Locomotives and some Diesels have been with us since post World War II. They were a main stay to power the locomotive. These motors were all produced in Japan except for the Pitman Motor which was produced in the United States.

About thirty five years ago the industry began changing over to the can motor. The can motor was introduced in new locomotives to be sold to the hobbyist. It wasn't until a few years later that the hobbyist could buy the can motor for personal use.

Why the sudden change to the can motor? What were the reasons for such a major overhaul? The following is a presentation of the reasons for those changes and the advantages as well.

The open frame motor was a nightmare to keep running. There were several reasons for this.

1. The brushes and armature are exposed to the atmosphere. This allows dust particles which are charged to accumulate on the armature and adhere to the brushes. This alone causes sever problems electrically. It takes more power to turn the motor which in most cases isn't there. That is it creates a resistance which bogs done the motor. 2. The accumulation of static charged particles on the brushes causes them to be ground down and become useless. These particles also can cause scaring on the armature which can make the motor useless. 3. The open frame motor requires lubrication at each end of the motor where the bearings are located. The manufacturers would place a pad around the motor shaft next to the bearings. Here is where you would lubricate the motor. The problem is that these pads would get old and shrink thus eliminating the lubrication process. 4. At best you can tear down the motor and rebuild/replace the vital components except the armature. This can be a difficult process and very time consuming. It doesn't mean the motor is going to run any better. These motors when left standing for any length of time usually did not run.

The can motor eliminated all of these problems and is far more sensitive to electrical input than the open framed motor. It was almost impossible run an open frame motor at low speeds where the can motor is suited for this type of operation.

The open frame motor is not really adaptable to the new DCC operations. This is the opposite for the can motor as it is suited for the running of locomotives which have the DCC decoders on board. The can motors are smaller than the open frame motors which made it easier for the hobbyist to install the new motor.