Armatures

Armature

1. ARMATURE

The copper five windings are wound thousands of times to create a coil. The windings are very thin and each winding connects to one of the commutator segments. A break in one of these windings will lead to either erratic running, or no running at all. The breaks are difficult to find and sometimes render the armature beyond repair. Excessive heat will damage these windings.

2. POLE PIECE

Shroud the sides of the motor, maximising the magnetic field around the copper windings. The more snug these are to the motor, the lower the current draw / more efficient the motor runs. Adjust with a pair of pliers but be careful the motor doesn’t rub against these. It is common for pole pieceS to vibrate against the chassis side, making for noisy running. They can be adjusted to prevent this. Early separators were not removable from the chassis, making it more difficult to remove the magnet.

3. COMMUTATOR

Made from metal, but surprisingly delicate. Be careful not to damage this by trying to scrape off deposits with a knife or metal instrument. Use a lint free cloth with IPA to clean it and chop down an artist’s brush to brush between the segments. Completely submersing this part in IPA will not damage it. If using a rolling road (i.e. loco is stationary but running, a chopped down cocktail stick soaked in IPA can be used to polish the comm surface, but be gentle). Be careful not to get oil on this component.

4. BRUSH HOLDER

Slots into the chassis and holds the spring and brush in place against the commutator. Can benefit from a periodic clean. The clearance between the brush holder and commutator is minimum – visually check the two are not touching (this will not happen if the components are assembled correctly).

5. BRUSHES

These are durable, yet will wear down over time with continued usage. A blend of carbon and some form of hardener, they will last a long time. If you plan to keep your locos for a long time then it might be a good idea to hold a few spare, since there was a shortage a few years ago and this lead prices to increase dramatically., A new batch was produced. Be sure to not get oil on these, and to clean them a soak in IPA is appropriate – making sure the brush face is clear of deposits afterwards. After re-insertion the brushes need exposure to a moving commutator in order to bed down properly.

6. SPRING

This applies the correct amount of pressure on the brush so that it makes contact with the commutator. Use the correct springs in order to achieve the appropriate pressure. These can also benefit from a periodic clean, since they can collect carbon dust / grime. Very delicate and they like to escape handle with care, and preferably on a tiled floor instead of carpet (easier to spot).

7. BRUSH HOLDER

Slots into the chassis and holds the spring and brush in place against the commutator. Can benefit from a periodic clean. The clearance between the brush holder and commutator is minimum – visually check the two are not touching (this will not happen if the components are assembled correctly).

8. BRUSH CLIPS

These simple components cap the brush holder ( brass cylinder) and prevent the spring and brush from falling out. They also act as an electrical conductor to the brushes. Another form of these, by way of a swivelling plate, are built into some diesel baseplates.