Got Curious working on a 2-10-0 (For the Electronically savvy)

[Irbricksceo]

So I have been having some trouble with my 2-10-0, I managed to figure out the pickups that lead to the drivers were causing the Locomotive to short and after removing the bottom plate to check on it, I blundered and tore the pickups and wire out, ruined the part... don't ask me how, luckily the parts department had some despite the locomotive being out of production. Anyway, while the part Is on order, I also figured I would drop a decoder into the Locomotive since I plan to go DCC soon and the fewer times i disconnect to Engine from the Tender, the better.

Anyway, While looking at the board in the tender, I started wondering... What are the various components for? The resistors are for lighting I presume, But I can't figure out the Capacitor and Inductors. Having been inside other Locomotives, I know they all have em, But i can't figure out why! Does anybody know what they do?

[Hunt]

Many countries require very strict electronic emission controls. In order to meet these controls we are required to install suppression capacitors and inductors on our locomotives. Most DCC decoders (including Bachmann E-Z Command decoders) can work properly with these components installed.  If you want to install a decoder that requires removal of these components, Bachmann will continue to warrant the locomotive so long as the locomotive is used in the US or Canada.

[Joe Satnik]

Dear Irbricksceo,

The brushes and commutators inside DC motors arc 'n spark, causing radio interference. (Radio is high frequency AC)

Inductors (aka "coils") pass DC but block AC.

                 Capacitors block DC but pass AC.

Clever engineers have figured out how to configure caps and coils to allow DC from the power supply through to the motors,

yet block the motor's AC RFI (Radio Frequency Interference) from getting out to the loco's wiring, wheels and track, which act like broadcast antennae.

In some cases these RFI filters can "mess up" the DCC signal, as it has some AC in it. 

If you do remove the caps and coils, each coil must be replaced with a short jumper wire.  The caps can just be cut out.

A throw-away resistor lead (excessive length clipped off after a resistor has been soldered into a circuit) can be used as a jumper wire.   

Hope this helps.

Sincerely,

Joe Satnik     

[richg]

I have worked with tuned circuits since 1953. Remove the caps and the inductors are not an issue at the DCC frequency. The residual capacitance is so low, the inductors will be like a piece of straight wire.
On the other side of the Pond, the DCC frequencies are the issue.
The real paranoid users strip out everything and hard wire.

Rich

[Irbricksceo]

Very interesting, Would not have though that they were used as RFI Filters, I can see it though I don't know just how much it is truly needed. I'll probably just leave as it is, Can't see it being that much of an issue But it is certainly interesting knowing that these models have such things inside.

[richg]

Very interesting, Would not have though that they were used as RFI Filters, I can see it though I don't know just how much it is truly needed. I'll probably just leave as it is, Can't see it being that much of an issue But it is certainly interesting knowing that these models have such things inside.

LC filter. The resistors are for the lights. Some PC boards have a ferrite inductor that looks like a green resistor. Check the stripes. About 4.7 uh
Some have a wire wound inductor.

Rich

[electrical whiz kid]

Rich G.  I personally don't think that is being "paranoid", as is a mechanically sound and soldered connection, if possible, will "out-trump" plugs, splice joints, etc, every time.  It isn't so much a resistance issue, etc; but more just the dependability of the whole concept.
Rich C.