To paraphrase Vane Jones, "Knowledge is of little value until shared with others."

Wednesday, October 17, 2012

Model Not Running & The Electrical Short Circuit

The very item which makes a trolley model unique can also be the model’s undoing. You place a trolley model on the track, place the trolley pole (pan) on the wire, turn on the power, and nothing happens.

The over all problem may be non-conductive oxidation or dirt on the wire, trolley pole slider or wheel, track, or wheels. OR, the model no longer runs due to an electrical short circuit.

If you routine for getting the model to operate due to non-conductive oxidation or dirt does not work, STOP trying to pass electrical current through the model!

When the problem is due to an electrical short circuit, the amperage of the power supply can be passing through the entire wiring of the model including the trolley pole.

Resistance in an electrical circuit causes the conversion of the electrical energy into heat energy (heat). The heat can cause problems. Soldered joints in models or wiring will un-solder causing wires to come apart and brass models to deform and come apart. Wire, which is metal in a thin, dawn-out form, will not only deform but will lose other physical properties.

The reason for this post is the affect of an electrical short circuit has on the trolley pole! When the total amperage of the power supply goes through the trolley pole; the wire used for the trolley pole, the material used for the trolley shoe or wheel and trolley base, the springs, and the screw and/or material used to hold the trolley pole to the roof of the model will be affected.

The most common affect I’ve seem is the deformation of the springs. First the springs will become hot and then glow until the electric current is turned off. After this the springs are soft and stretched-out. The springs will no longer hold the trolley pole up to the trolley wire. The only way to get the trolley pole to work again is to replace the springs.

Recently I obtained a streetcar which would not run when placed on my test track. The test track is a 36” long straight piece of track with overhead wire. An old power supply is used to power the test track. To see the amount of current used both a voltmeter and ammeter are part of the electrical circuit.
This photo is the power supply installed at 1 end of the test track.
From left to right - a brass rod line side pole with the positive power supply attached with an alligator clip.
At the bottom right is the negative power lead attached to the track.
The black electrical panel part in the center contains the 2 meters.
The black wire coming out of the panel is the positive and negative power leads with alligator clips.
The use of the toggle switch in the bottom center of the panel is unknown.
The toggle switch at the bottom right of the panel controls the direction.
At the right is the small but useful power supply. 

The voltmeter and ammeter are an important part of the circuit. You can tell immediately the electrical “condition” of the model or whatever is connected to the wire leads of the power supply.

Recently to test a newly acquired non-operating model (without disassembling the model or placing it on the test track) the positive (red) lead was connected to the trolley pole and the negative (black) lead to the power truck. The model didn’t run.

Next, the trolley pole was removed (unscrewed) from the model. The pole unscrewed unevenly from the model (This turns out to be an interesting observation.). The positive lead was attached to the 2-56 screw sticking out of the model’s roof. The model still didn’t run.

I knew there was an electrical short circuit in the model. Without knowing exactly where the short was, I decided to replace the “wiring” from the inside of the trolley base to the motor lead outside the model on the floor exterior. This was estimated to be a 30 minute task.

Without going into too much of a discussion, the model was wired-up so the power truck could be easily electrically disconnected from the model. At the same time the negative ground was brought-up into the model. This later part was done for the future installation of interior lighting in the model.

Back to my interesting observation of the difficult trolley pole removal from the model – it’s the reason for this post. The correct trolley pole base for the model is a 4 or 2 spring vertical. This was on the model when I got it. Observation of the trolley pole base disclosed the vertical part of the base was curved.

The springs were removed to be able to better see the base and perform corrective actions. The vertical part of the base was deformed when the full amount of electrical current of the power supply went through the trolley pole. The piece of metal heated up enough to become soft. The action of the springs was strong enough to cause the heated piece of metal to take on an “S” shape.

The part of base which was deformed was a lost wax casting. Small protrusions were filed off. Then the trolley base was placed in a vice to apply enough pressure to straighten the metal casting.

The springs were replaced and the trolley pole moved up and down without any problems. To blacken the part of the trolley pole which had deformed, the lower portion of the trolley pole was dipped into Neolube #2. At the same time this will improved the electrical connection where the 2-56 screw, screws into the trolley base. Allow the Neolube to dry first before attaching the trolley pole to the model.

The bottom line of this post is when 1st testing a model which you have never seen run, test it with a power supply having both amp and volt meters. If there is a short, high amperage draw for a comparable model, immediately turn off the power to avoid any damage to the electrical circuit.

If a model with an electrical short circuit is allowed to have high amperage go through the model for an appreciable length of time, inspect the model including the trolley pole for damage. The trolley pole may have been damaged in a way which alters the geometry of the shoe or slider and the trolley wire.

Trolley poles are expensive. But at the same time they are the part of the model which sets it apart from other railway models.


Sunday, October 7, 2012

East Penn Trolley Club and Additional Vendors Listed

Three Chicago area retail hobby shops have been listed at the bottom of this page under "Traction Suppliers & Chicago Area Hobby Shops With Web Sites".

Each is unique and has carved out a particular niche in the O scale market besides stocking the normal modeling supplies found in other hobby shops.

Finding a retail store (hobby shop) which will stock trolley parts can be a problem. This is why trolley oriented vendors are listed at the bottom of this page. A hobby shop near your location can supply the items common to all model railroaders.

In posts in this blog are mentioned specific vendors for unique items covered in the post. When possible a link to the vendor is provided.

While I know there are other hobby shops which stock HO models, please recall this is an O scale oriented blog. I have very little knowledge about HO trolleys and models.

It's important for modelers to know the hobby shop(s) in his or her area to be able to obtain the day to day hobby supplies. 

One exceptionally useful web page is the list of trolley specific vendors provided by the East Penn Trolley Club (EPTC).

By the way, are you a member of the EPTC? Here is a link to the membership application.  Why not join?

The next biannual EPTC 21st National Model Trolley Meet is planned for May 2-5, 2013. It will be held at The Greater Philadelphia Expo Center at Oaks. Check out this link for more info.