Traction engines

[Anonymous]

I am building a model of a rod drive electric engine. Are the drivers quartered the same as on a steam locomotive, or does it really matter? The engine is being built at 1 1/2" to the foot scale and will be driven by an electric motor. On a steamer, quartering is necessary or the engine would not be able to self start, but on an electric, there is one power source.

[CSSHEGEWISCH]

I'm going to go out on a limb and suggest that the rods would not be quartered since the drive source is rotating instead of reciprocating.  They may be 180 degrees from each other in order to lessen the counter-balancing that would still be needed.

[Anonymous]

Thanks for your reply. It's just what I thought too. It shouldn't be much different than a diesel or other electric.

[J. Edgar]

well heres my .....this pic shows the rear drive set of a PRR DD1 quartered around 90 degrees....is ths typical?? dunno.....but you can see the counterweight of the rear drive shaft is off about 90 from one side to the other...i would assume the front set is the same....

 

[tomikawaTT]

The drivers are quartered and cross-balanced to minimize asymmetrical stress on the frame.  Quartering to balance piston thrust isn't necessary in a siderod electric, but the dynamic augment of reciprocating weight is still there.  And, if the rods were set at zero or 180 degree offset, the rods wouldn't be able to transmit rotary motion from the motor to the wheels.

Chuck

[Anonymous]

Thank you all for the replies. I think my question has been answered. BTW, the DD-1 model is on the back burner. I am working on an electric (class D, 1-C-1) used on the SJ, a Swedish line that operates some very interesting engines. The reason is the class D was built with a wood body, hence easier for me to build. The DD-1 would be a steel body. Although I have the means to work either wood or metal, I prefer wood.

[timz]

the dynamic augment of reciprocating weight is still there[in a siderod electric]

What reciprocating weight? 

[timz]

I think my question has been answered.

One guy answered yes, the other one answered no. Which one did you choose? 

[Anonymous]

I think the concensus indicates the drivers are quartered and that's what I'm going with. I will post pictures of the finished engine at a later date. For now, progress is slow as I have to reinvent the wheel as I go. Here is a foto of the engine I'm building.

[tomikawaTT]

the dynamic augment of reciprocating weight is still there[in a siderod electric]

What reciprocating weight? 

Looking at one side of the locomotive only, the weight of the siderod and main rod cannot be fully counterbalanced (the main driver wheel weight can't be made big enough.)  The effect is more noticeable in the horizontal plane, and is offset either by having pilot wheels (as in the DD-1) or by having a longer rigid wheelbase.

[timz]

the weight of the siderod and main rod cannot be fully counterbalanced (the main driver wheel weight can't be made big enough.)

You agree the counterweight could have been bigger than it was? (On the DD1, anyway.) So why didn't they make it bigger, if more was needed? We've all seen pics of semicircular counterweights.

And no reciprocating weight-- right?