This topic is probably not new. How can I reduce the speed on Williams locomotives when operating using conventional variable voltage power transformers? Can I rewire the twin motors to operate them in series?
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Yes, this has been discussed.
Yes, wiring in series works very well, many of us do this. It is easy and does no harm. I wire my Williams in series.
-Ken
That is the best way to do it.
Another solution is to replace the worm gear on each power truck with another worm gear designed for slower speeds. But I don't know of anyone who makes such worm gears, and that project would demand some skills to get everything just right.
Here is a link with pics that show how easy it is to accomplish this:
Marty
I used the diode method Dale references. I am no electronics person, but the schematic was easily followed.
No problems running regular transformer controlled conventional or when running conventional through a TPC400 with a CAB1 for control.
Series wiring works well in most cases but has its drawbacks. Two identical motors in series will distribute power evenly if wired in series and have the same electrical resistance. However when an engine enters a curve one motor will spin faster than the other and motor resistance changes with speed,thus one will run slower than the other and the electrical load will not distribute evenly worsening the problem. Also sometimes gears in 2 motors have uneven drag.
This may not be noticeable on shorter locos but I had some Williams E7s and GG1s that simply would not run right wired in series. On a corner at slow speeds one motor would actually lock up while the other one would speed up and drag the engine. Dale Manquen of the forum actually designed a compensation circuit to overcome the problems of series wired motors.
I opted for the diode method after experiencing problems with series wiring. The only drawback of it is the power expended by the diodes and work and expense of installing them. They also works on single motored units. In addition the diode string can be tapped to run 3 volt bulbs or LEDs for constant voltage directional and non directional lighting,headlamps,backup lamps etc.
Dale H
This gets asked so often you'd think some aftermarket control company would see the market opportunity for a kit: a small board with the diodes ready to go.
Originally Posted by artyoung:
This gets asked so often you'd think some aftermarket control company would see the market opportunity for a kit: a small board with the diodes ready to go.
If the train companies would listen and double the gear ratio,none of this would be necessary.
Dale H
Originally Posted by artyoung:
This gets asked so often you'd think some aftermarket control company would see the market opportunity for a kit: a small board with the diodes ready to go.
K-Line eventually added a DPDT switch on the bottom to select series/parallel.
Where would the diode string be placed on a 2-motor unit? I seem to remember that each motor has its own harness that plugs into the reverse board. Would I need a set of diodes for each motor?
Only 1 set is needed. Sometimes motor wires go to the board in pairs,a total of 4 wires. Both of 1 pair then are put in series with the diode string. Treat them as one wire so a pair in and a pair out of the diode string. If 2 yellows and 2 blues go to the board for example, Cut the 2 yellow and insert the string in series so that 2 yellows go to the board and 2 go to the motors connected in series to the diode string. The blue wires are left alone.
Dale H
These engines were designed to use with modern transformers. No problems with jack rabbit starts if you do so.
With a modern 150 watt Williams transformer I can make both Williams and K-Line engines do a very slow crawl.
Originally Posted by KMK:
These engines were designed to use with modern transformers. No problems with jack rabbit starts if you do so.
With a modern 150 watt Williams transformer I can make both Williams and K-Line engines do a very slow crawl.
That is my experience also. I add inrush current suppressors (NTC Thermistors) to my single motor steamers. This simple mod along with transformers that start near zero volts allows 2-3 mph speeds. Speed estimate based on tracking a MTH DCS engine running at 1 scale MPH. I am still working on the proper device for two motored engines.
Pete
Hello guys and gals.......
My new Williams NW-2 will crawl slowly with my Z4000. I was impressed that it can do that as it is. The engine give good slow speed with 3 weighted cars @ 7.5 volts (40 scale MPH). I am running the short train on my 4 by 6 using the 036 fastrack. The cars are Williams 4 bay hopper, MPC lionel 9726 boxcar and Williams caboose. The cars have 2 oz. of stick on weights and up graded with older MTH die-cast trucks. I think it will help slow dow the Williams engines if you use weighted down cars like adding few oz. of stick on weights. The weighted cars with die-cast trucks give good tracking when backing up the train on the yard. The Williams NW-2 is a GREAT little switcher.
the woman who loves the S.F.5011,623
Tiffany
Not all Williams start like jack rabbits! The GP-9 starts at a lower voltage but the SD-45 takes a good bit more voltage to start. Another thing that may effect speed is using a bridge rectifier in place of a circuit board, the circuit board takes about one volt away from the motors. I have removed the circuit boards and installed bridge rectifiers in a couple of older F-7's and they run a lot faster.
Also what transformer you use can and will matter what speed your Williams start at.
I was able to buy a very nice transformer that has two voltage selections on it, and works great with my Williams engines. A Troller Company TAC 2001, has two train controls and different voltage settings.
Lee Fritz
Originally Posted by phillyreading:
I have removed the circuit boards and installed bridge rectifiers in a couple of older F-7's and they run a lot faster.
Lee Fritz
Instead of using the bridge rectifier,you can use 2, 6 amp diodes instead. Half wave each motor,one with the top half and one with the bottom half of the sine wave. It is equivalent to series wiring without the drawbacks described earlier. An optional 470uf 35 volt capacitor in proper polarity across each motor will make it run super smooth at low speeds.
For you who series wire, turn your engine upside down and run the motors at 8 volts with alligator clips and wires off a transformer. Put your thumb and stop or slow one of the motors and you will witness the other one speed up,this is due partly to uneven voltage distribution described earlier.
Dale H
It would be great if lots of us let Bachmann/Williams know that in the future it would be useful to gear the fleet of engines lower this would solve most of the issues.
I find I am running at full speed with a passenger set at just 7 volts barely enough to light the headlight.
The kids with a regular transformer have the engine flying off the tracks on the first turn and makes for troublesome switching or low speed work.
I have a fleet of Williams engines and have the transformers with a wood stick taped to keep the throtle from being pushed up to high by visiting guests or when at train shows with the kids running the trains.
Actually its not the gearing that is the main problem. Williams uses relays in their E units. The relay contacts don't close until about 4 volts (RMS) AC is applied to the tracks. Track voltage is rectified and sent directly through the relay contacts to the motor rather than through triacs or transistors used in most other electronic E units. When you rectify, then filter AC you get a peak DC value 1.4 times the AC RMS voltage. This translates to about 5.6 volts that the motor starts with. Transformers that have a starting voltage of 6-8 volts only exacerbate the problem.
The plus side of relay E units is they are very rugged. The downside is this high starting voltage.
Pete
