Few Questions about Sunset M

[NW Modeling List]

On brass steam locomotives, the entire locomotive is electrically tied 
to the engineer side drivers (+). The entire tender is tied to the 
fireman's side wheels (-).

If you are correct that the red arrow is pointing to the headlight wire 
as the only wire to the upper motor tab, then I have to ask if there is 
a blob of solder connecting the motor tab to the metal case of the 
motor.  If so, this connection has to be unsoldered. The 2 motor tabs 
sticking out of the plastic end cap of the motor should be completely 
isolated from any metal parts of the locomotive or motor casing.  These 
2 tabs should only connect to the motor tabs of the decoder.  The top 
tab should be positive and the lower tab negative.  If one of the motor 
tabs is permanently connected to the motor casing, then you have to 
completely insulate the motor casing from the motor mount with double 
sided foam tape or Kapton tape.

The 2 leads from the headlight bulb should only connect to the headlight 
tabs of the decoder.  One wire to a light function tab, the other wire 
to the light common tab.  Resistors may be needed. The wire from the 
green arrow should go to the left track connector of the decoder, if the 
decoder is mounted in the locomotive, otherwise just unsolder the wire 
from the tab and leave it unused.  If the decoder is tender mounted then 
the left track connector wire should be soldered to the floor of the 
tender.   A wire soldered to the locomotive  frame goes to the right 
track connector of the decoder.

The yellow arrow is pointing to the torque arm of the motor mount which 
should not have been used for electrical conductivity.  To improve 
electrical pickup on brass engines (very useful for sound decoders), it 
is possible to add wheel wipers to the engineer side of the tender and 
to the fireman's side of the locomotive.  Due to the placement of 
insulation on brass drivers, any wheel wipers are limited to the tread 
surface of the driver.  An alternative to added wheel wipers, is a large 
"keep alive" capacitor available on some decoders.

You can test the motor and mechanism for binding by hooking the 2 motor 
tabs directly to a DC power pack using some jumper wires with mini-hooks.

David Jacobs
Stillwater, OK


On 11/17/2013 5:46 PM, NW Modeling List wrote:

> Thanks for the replies everyone. I have a rear coupler installed. 

> looks like the front coupler is going to take some more work. I took 

> off the boiler, and had a look at the motor. I'm a little bit 

> confused. Attached to my email is a picture. The red arrow points to 

> the wire for the headlight. The yellow arrow points to what I assume 

> is the pickup for the front/engine. The teal arrow points to the screw 

> that goes to the drawbar/tender. How to install the decoder? More 

> directly, solder what to what? Is the screw at the yellow arrow 

> removable? Having a tough time getting it to move at all. Also, still 

> confused about that is picking up what current and how power is 

> transferred. I can take more pictures if people need to see it to help 

> me out. Thanks for the help!

>

> -Brad Custer

> Columbus, OH

>

>

>

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