Diesel Loco--Series vs. Parallel Wiring

[GTBob]

Right now my WbB GP9 runs at about 40 scale mph using 8.1 volts (w/ a Lionel Postwar ZW Trans.).  IF I switched the motors to run in series-----About how much voltage would it take to run at the same scale speed?

Anybody out there have any idea?  Any help would be appreciated.  Thanks in advance....

Regards,

GTBob

[GTBob]

AWWWW come on--someone out there has done an analysis on this and has an answer.

Thanks,

Bob

[r0gruth]

I can't answer your question but all of my two motored locos,all Williams,have been changed to series wiring.

I like this because they run slower at the same voltage and have not,IMHO,lost any pulling power.The speed is enough slower that I don't worry about my grandson having locos become airplanes.Smooth starts are also easier,IMO.

My guess is that it might take around 12 volts.

[671]

    In reference to the question of the difference in speed to voltage setting.
I would guess that one would need to double the voltage input when the motors are wired in series. The reason for this thought, is that inorder for the loco to do the same amount of work i.e. Speed and Load ( train length ) the two motors would require the same amount of wattage. Now since wattage is the based upon......
  Volts X Amperage =  Wattage by running the motors in series as opposed to parrallel the resistance in that motor circuit has doubled. This would cause a need to double the voltage to allow the motors to consume the same amount of total wattage to do the same amount of work.
     This could be easily visualized by a simple light circuit. Two twelve volt bulbs wired in parrallel ( Like the motor circuit within the locos ) powered by by 12 volts, would be lit up to their design brightness.
     Now if you wire the same bulbs into a series circuit, you would need to double the voltage to achieve the same brightness. 24 volts ( the force needed ) would then produce the needed wattage to power the circuit by over comming the doubled resistance.   I hope this is clear, 671

[GTBob]

Thank both of you for your comments.

671------Your explanation certainly makes good sense to me.  Guess you'd better have a 20 volt trans (ex. Lionel ZW) to get some decent speed out of a series wired 2 motor loco., right.......

Regards,

Bob

[CandO]

Hello GTBob,
I have been very happy with the locomotives that I series wired.
If you would like to give series wiring a try, here is a link to my How-To using an E7.  I did not cut any wires to do mine.  It is very easy to do and very easy to change back if you are not happy with the results.
Click on each photo for typed information:
http://s574.photobucket.com/albums/ss182/SunfireGT1996/Series%20Wiring%20WBB%20E7/

Another option is using diodes.  I have not tried this method, but I plan on trying it when the Williams Norfolk Southern F3s arrive.
OGR forum member Dale H put together a How-To using diodes:
http://www.jcstudiosinc.com/BlogShowThread?id=488&categoryId=426

[GTBob]

Hello CandO-----Thank you for the info you provided. 

I've previously seen your "How to Do" on series wiring (It's good work).  Sure seems simple enough---think I'll give it a try.  As you mention--it's easily reversed.

I've also seen Dale H's (OGR) post on use of diodes to slow down the loco.  Where would you splice in those diodes on a WbB/WbW 2 motor loco?   The only place I can think of is the wire coming off the power roller (Center rail power supply) and going to the reverse board.  Am I correct or am I in outer space w/o a space suit???

[CandO]

Dale H says you just cut one of the wires that goes from a motor to the reverse board.  So, on my Williams by Bachmann that would be the blue or yellow wire that I would tie into...the same wires that I are changed for series wiring.

[phillyreading]

While everybody is trying to wire things in series, has anybody thought about using a transformer with lower voltage capabilities?
Troller Corp. used to make a transformer that has both 0 to 9 volts and 0 to 18 volts. The model number is the TAC 2001, has 150 watt output and accessory hookups.

Lee F.

[671]

Hi Phillyreading, I believe that several positives can become available by the series wiring of the dual motor locos.
1. Running the locos at the higher voltage ( motors in series )allows the standard lighting in the loco, passenger cars, spot light cars, cabooses to be brighter and smokers ie caboose smoke to emit more smoke.
2. Voltage drop at the higher volltage settings is not as senitive as it is at lower operating voltages. I.e. A drop of one - two volt at 8 volts may be more noticable ( 1/8-1/4 power reduction ) than a one-two drop volt at 16 volts ( 1/16-1/8 power reduction). This voltage drop could come from the upside of a hill. The amperage draw will go up and this will cause a voltage drop. Resistance in the overall location of the loco to its' nearest power source. ( Track lenghth ). Dirty track. Any intermittant added load... Switch track, crossing gates, milk cars unloading,etc.
                            Thanks again.....671

[phillyreading]

671,

I have no problem with the way Williams engines run for me, other than an occasional reverse board that acts up. Never did I wire a Williams engine's motors in series, to me they would be too slow.
To you this will seem odd, but I took the circuit board out of my older Santa Fe F-7's(an A-B-A set) and replaced it with a bridge rectifier. Why did I do that? I wanted a little more speed from my F-7 diesel and got it(about a 10% increase). The set came with six El Capitan passenger cars, probally 70 foot extruded alluminum, and the engine was sluggish in my opion, would barely do 25 scale MPH.
I upgraded the one engine, as it was unpowered, but after installing the upgrade kit I noticed that the new motors out run the old motors very much.
So I installed the new motors into a Pennsy F-7 and took it's old motors and was able to match the speed of my other powered F-7. Since the upgrade to bridge rectifiers I added two more passenger cars, an eleven unit passenger train with good speed.

Lee F.

[phillyreading]

Hi 671,

Forgot to mention that when I replaced the circuit boards with bridge rectifiers that I lost direction control.

Maybe my electric power is lower down here in Florida but I have not seen the need to wire a set of Williams motors in series, even when using my post war 275 watt ZW or my 250 watt Z transformers.

I know how to wire stuff in series. That is a piece of cake! But how about series-parallel, for electronic circuits?

Lee F.

[671]

Hello again Phillyreading,
       I am in agreement with you. I had just started purchasing Williams Locos this past December. I first landed a Semi-scale Hudson...nice puller,poor smoker. Next aquisition...GP9 Union Pacific...Great runner after breakin no need to series wire. Next a Bershire...Great Northern...not as good a puller as the Semi-Hudson, 8 wheels touch the track, only two have tires. Wheel spin with 5 car ore dump and 5 hopper cars and caboose all post war on hill. Ok smoke. Yesterday, stopped at Trainland Lynbrook N.Y., with cash burning a hole in my pocket. GP38 Santa Fe Warbonet. Great looker, Great puller, nice low speed with excellent coasting plenty of controlable power on ZW 275.
       P.S. I don't quite know what you mean by series parallel. Two series circuits wired parallel to each other?
                        Thanks again...671

[RNF]

Hi GTBOB,
     In answer to your questions, I suggest that you first go to a previous post....http://www.bachmanntrains.com/home-usa/board/index.php/topic,14649.0.html. The responses there will tell you the benefits of wiring in series, how to perform the wiring and also how to put in a switch that will allow you to toggle back and forth between series and parallel at your whim.
     I have performed this procedure on a Williams GG-1 and a GP9 and they perform flawlessly in either mode. If you have a Lionel ZW transformer, will be pulling illuminated passenger cars and are looking for more prototypical slow starts, to me, this procedure is a no-brainer. With a ZW in parallel wiring, the engines take off like a shot and is not realistic at all.
     I have done some tests as you requested to give you some quantitative comparison. I put my GP9 in a consist of ore cars as well as a crane car and searchlight caboose (a total of 9 cars). I first ran it in parallel mode to reach a speed that bordered on going airborne (my outer loop is on a board 13 1/2 ft long with 54 inch curves). I did not want to go faster than 11V. I then switched it to series and 18V brought it to the same point. I then ran it in parallel at what I would consider normal running speed. I completed the loop in 10.65 seconds. The transformer was set at about 9.5 V.  I switched to series and to get it to do the loop in approx. the same time, it ran at 16V.
     I very rarely use the switch in the parallel mode. The engines start too fast, my illuminated cars are dim and....I've had friends over to run my trains and they've run them off the tracks . I can't let that happen anymore. More times than not, I use the switch to show people the dramatic difference in the way the engines perform. I'm considering doing this procedure to my NW-2. I love the way my PW Lionel switchers do the "6 volt crawl". The NW-2, wired in parallel and powered by a ZW, can't come close to that. And by the way, the bell and whistle functions are not effected by switching modes.

Hope this helps...

Regards,
RNF

[GTBob]

Hello RNF,

Thanks much for the info you provided.  That is exactly what I'm looking for.  Based on the feedback from most, it appears series wiring is the way to go.  That will be my next project.

Thanks to all for providing some really good info.

Regards,

GTBob