Williams GP30 Speed Control

I don't have the GP30 but I have some other Williams diesels.  A common "trick" is to re-wire the motors in series rather than parallel as (at least all of mine) it came from the factory.  This cuts the voltage to each motor and improves slow-speed control, which is a common issue with owners.  It is a common modification.  someone who has the GP30 can perhaps tell you if the motors, like on other WBB diesels, are wired in parallel.  All of my WBB diesels were. 

Lee the same trick will apply. The new sound board plugs into the 6 Amp board. The easiest way is to pull the connectors out of the board. Each motor( Blue&Yellow)/Ground( Black)/3rd rail pick up( red) will have its own connector.  One connector for each motor and wires

 

Doug

Well my dealer thinks it is bad reversing board and wants me send it back on my dime for repair. I have my doubts and believe re-wire motors in series would correct the problem. 

I have changed all of my WBB GP30's; GP38's; Scale Alco FA's; and F3's to series wiring.  It is incredibly easy to make the change and immeasurably improves the operation of the engine.

There have been several threads over the years that provide the simple directions needed to convert your WBB engine to series wiring.  If you use the Forum search function you are certain to find one of those threads complete with photos.

Curt

Thanks guys, I have found some Pro Hobby Designs wiring info from search. Will review this weekend.

One thing I can say about the Williams engines is that I don't use them for switching duty, usually run too fast for that.

However I have never wired any Williams engines in series, it's any easy do for me but mainly I want more power from my engines verses low speed. I usually have about 12 to 16 freight cars behind my Williams engines so speed is not that important to me.

 

I don't have any Williams by Bachmann engines mainly because of the price of the engines, even with on-line dealers the engines are expensive.

I have heard from others that the wiring is about the same for the motors.

 

Lee Fritz

WBB engines run a lot slower, smoother, when wired in series, but they can't compete with Legacy and PS3 at low speeds, even when running in conventional - those systems just have smarter (read, more expensive) electronics. Still, they do alot better when wired in series.  I'm surprised WB B doesn't just make the change, frankly, but I guess they know what their target market likes as far as speed goes.  

I was really curious about the sound system used on these locos so I had a look.  They are built by Soundtraxx.  One thing I noticed is that there is a capacitor that is electrically across 3rd rail and ground.  This can cause false triggering of triac based ac transformers. 

I am surprised that nobody complained earlier.

 

You need a bias resistor in series with this capacitor.  Actually the circuit needs to be re-designed.  I had a similar problem with the first RoW digital sound system.  Lionel had just come out with a solid state transformer (MW?).  Locos would have two speeds, off and 120mph.

 

Regards,

 

Lou N

 

 

I suspect the reason for not wiring the motors in series is that it limits the pulling power of the locomotive and the top speed. 

Series wiring will only cause it to rocket off at less than light speed.

There is an old trick using a large non-polar electrolytic cap to make solid state whistles and horns work with marginally effective (tired) whistle buttons.  The cap, however, causes a solid state transformer (triac driver) to loose its mind and fire full on.  

I saw the cap on the Soundtraxx boards.  This is what happens when you get an HO DCC electronics firm to do your tinplate designs.

Like I said, I had this problem with the first RoW locos.

 

GRJ- always happy to discuss electronics.  We can get into the technical details off list if you like.

Lou N

I've wired them in series, I can tell you first hand that it does limit the maximum speed and pulling power.  As to whether that will be significant is an individual judgment.  I rarely worry about the maximum speed anyway, but just making an observation.

 

I wire all of my WBB in series, and put a thermistor or two in the series circuit (covered on other threads here).   Works great, is easy, brings the sound steps better in line with the actual speed.   Top speed is still too fast even in series, so no loss there IMO.   Williams pulling power is so strong even in series I cannot stress it with my size layout and train length (up to 20 cars no issues).

 

-Ken

I use inrush current limiting (thermistor) devices picked up from DigiKey.  These are CL-160, P/N KC016L-ND. 

 

The thermistor is simply wired in series with the two motors.   Blue wire from one motor connects to the thermistor,  other side of the thermistor connects to the yellow wire from the other motor.

 

The thermistor is a resistor whose resistance varies with temperature.  As it gets warmer, the resistance decreases.  It can be used to limit the initial flow of current and voltage for a gradual start.   On the GP30, I used only one.  On my older engines I use two.  The GP30 is not quite the racehorse that older Williams locos are, and I think two thermistors might take "too much off the top", but I did not experiment to confirm.

 

These are 2.8 Amps, you can find them at higher current levels if needed.  Resistance varies from 5.0 Ohms at room temp down to 0.2 Ohms when warm.

-- Ken

Hen,

 

What transformer do you use?

 

Lou N

Lou, I use the Lionel CW-80.  -Ken

Thank you Ken,

 

Those have a power MOSFET output so there won't be any light speed runaways with that transformer.

 

Lou N

I'd love to see a picture or two of someone's WBB GP30 "wired in series" wiring.  I'll try the search tool here to see if I can find some, but if anyone out there has pics and the time to email them to me (murnane@gmail.com) I'd appreciate it.

^^^^^

I found the following via searching the forum, could it be this simple?

 

http://s574.photobucket.com/us...ringdiagram.jpg.html

 

 

Yes, it is that simple, nothing to it.

Murname:

Sent you link to earlier thread posted by O-scale that provides instructions and pics.

Curt

Lou, Are you talking about Williams True Blast sound, because I did not see Soundtrax marking on it, though other types of Williams may have other sounds.

 

Some transformers also just start at higher initial voltage than others.  The voltage may be high enough for Williams to go too fast for an operator.  An easy test is to unplug the sound system and see if it slows down.  I doubt it from what I have seen.  G

Thank you all, I believe I just successfully accomplished my first modification!

 

 

There were two things to note:

1)  The motors were wired into the same connector, 2 yellows -> one slot, 2 blues -> one slot.  Because of this, I went the route of cutting the wires and soldering/wrapping them with electrical tape

2)  Ahhh, when I opened her up a small plastic "lens" fell out, I couldn't for the life of me find out where it belonged, so I put it in my parts bin because I had no idea where it was supposed to go.  Ideas/suggestions on this one are welcome, I just wanted to get the patient back together as I was kind of nervous doing this.  Picture of the "extra" piece is below.  Note:  all the lights seemed to be working fine.

 

A test run for the GP post-surgery indicates that all is well and it's most certainly more "slow speed friendly" now.  Thanks to all (Ken, Juniata, surfimp, etc.)  for the insight! 

 

 

extra lens/piece - no idea where it should belong

 

 

 

That lens is one of the headlight assemblies, you'll note that either the front or rear headlights now just have holes.