How do I wire a KW transformer for switdh power

The KW is an odd duck in this usage. You can't use 14v as you have discovered, as it does not have a common ground with track power.

That leaves you with 6v or 20v, neither of which is ideal, but 20v is better for powering 022 style switches.

OR, run the train on A-U, run the switches on "B"(B-U), adjusting the voltage for optimal performance.

The only way I could see to get 20v constant was to wire from d to U which makes no sense, so where would I hook d? it is not common with ground, or am I missing something obvious here. If the 14v was ok, how would that work for a switch, I could not read 14 anywhere else except across those terminals. Can you hook one to ground? 

As the previous gentlemen have said, the KW is an odd transformer in the sense that it does not provide a 14 volt U-referenced post.  You need to be careful, in fact, not to let any metallic portion of an accessory powered by C-D (like the base of a log loader, etc) come in contact with the track ties. That would cause a short circuit.  To recap:

A - U is variable

B - U is variable

C - U is  6 volts fixed

D - U is 20 volts fixed

C - D is 14 volts fixed

You must use a post that has U as a reference (return) for any accessories or switches that require that their return be via the outside rails.

You can use A, B, C, or D.

You cannot tie either C or D to U, because that would create a short circuit.

Since 6 volts is too low, your only choice, (other than "wasting" one of the variable handles) is to use D - U whose voltage is a little high.

If you want to be a little creative, you could get yourself a doorbell or thermostat transformer that supplies 12-14 or 16-18 volts, and use it for your track switches, making sure that it's in phase with your KW.  Fire alarm systems use a plug-in transformer that supplies 12-14 volts at sufficient power to run switches and signals. They are available at electrical supply stores.

Here's one, as an example:

http://www.homesecuritystore.c...-interlogix-pip12vdc

Or go one step further and get a 1033 and phase it with the KW.  That would allow fine-tuning the output for exactly the desired voltage. 

This method (adding either a fixed or variable supply) is electrically equivalent of "adding on" another U-referenced post to the KW.

This like many other wonderful Lionel innovations, just did not make sense, and your excellent explanation, did confirm that I was not loosing my marbles, it did not make sense, because it doesn't make sense!

Thank you my friend. I think your suggestion of phasing a small additional transformer makes the most sense.

You're welcome. Check my message above. I added a link to a typical alarm Xfrmr that supplies 12 volts at one amp. You can find them cheaper than that one.

Tin,

   There is really no problem use a ZW channel to power all your switches.

Rob just gave you the best way to run your KW.

PCRR/Dave

I agree, but, what if the guy wants to run 2 trains?

Like others have mentioned about the KW, I use the accessory terminals to power lights or other accessories and not the 022 switches.

The Lionel post war ZW would be a better source for powering an 022 switch. Use terminals B-U or C-U as these don't have whistle or direction control on them, set the voltage to where you want it.

If you are going to phase any transformer make sure it has AC output. Don't use a DC power pack as the AC & DC will fight each other due to wave form.

Lee Fritz

Thanks Philly, I am gratified to find out I guess I wasn't loosing my marbles after all. There should be a way to convert the transformer to do what we all now know it should be doing. I  have a couple of them here. Will take a look at one when I have a chance.

I don't know too much about the KW's wiring inside or circuit breaker but the post war ZW has one circuit breaker on the common side that mainly protects the transformer. The KW is more of a multi-tap transformer and I don't know if the multiple taps are off the same set of field windings or a separate set. The power could devert off before it gets to the control handles or could be a separate set of windings.

Lee Fritz

"If you are going to phase any transformer make sure it has AC output. Don't use a DC power pack as the AC & DC will fight each other due to wave form."

Sorry, that's SLIGHTLY misleading information.  While it is true that you cannot use two supplies, one A-C and one D-C, for interconnecting traction circuits using the phasing method, there is no reason that you cannot use any two (or more) supplies, of the same or different polarities, voltages, waveforms, etc,  together, with a common return, for any application other than traction circuits.

Phasing is only required when two similar A-C supplies are expected to play nicely together in a situation where a train passes from one track (with its A-C supply) to another interconnected track (with its A-C supply).

If your track switches work better with DC, then one (either) side of a floating D-C supply can be wired in common with the traction power return ("outside rail") wire.  This is not called "phasing" -- it's called "creating a common return."

Check the archives for (what I believe is) the most recent answer from me on this subject.   Search for my user name and the terms "telephone power supply."

Seems to me a default to the 20v taps for a KW to power O22 switches is setting yourself up for a disaster! 

Granted, the actuation, being essentially momentary, should survive the higher-than-recommended voltage.  

However, even with an 18v bulb in the motor housing which will be constantly at 20v the bulb life will be significantly shortened and the excessive bulb heat will warp/distort the lamp housing and its red-green lenses.  Not good!!

I would say that short of using AU or BU taps, setting the voltage at a minimum acceptable (operation + bulb intensity...using an 18v bulb), a KW is a NO-choice for this situation. 

But that's just my opinion.

KD

"...a KW is a NO-choice for this situation. But that's just my opinion."

An opinion shared by at least one other person. That's why I recommended the cheap and reliable 12 Volt, one Amp, A-C wall wart, used to create an extra "outboard" KW choice.

Good advice, I did not plan on using the full 20V I like the 14 or 15 volt range for the switches. Will let you know how I did.

Not enough power. 1 amp will power the bulbs on 2-3 switches and controllers with no overhead for actually throwing the switch.

I guess that each lamp draws about 1/10th amp, so yes, it would seem that a three amp supply might be better.  Looks like the LED solution is called for.

I put on an ammeter just for fun and I measured about 1/3 amp. Sooooo  .33amps X 12volts =just under 4 watts

Per bulb. So a 12 Volt, one Amp, A-C wall wart could light 3 switches w/o controllers as that would be a 12 watt load.

I like you have been to many train shows, and there are always a bunch of cheap old transformers with a single adjustable output. I've seen them as cheap as 10 bucks. Seems to me that  they would be a better solution for a once and for all deal. Adding one of those to the system should handle all the needs of 1/2 dozen switches or so. I just did not understand why the KW would not have been designed to accommodate that. I guess the answer is the same as to why did Lionel design a uncoupler/unloader switch that would short out if you pushed both buttons at the same time, or instead of designing a bootstrap plug with a single conductor, make it with 2, a track pliers that would also compress the bottom portions of the rails,  or the list keeps on going. It took K line to change the design from the O22 switching to a micro switch that was completely sealed and probably last forever. I can appreciate the 1930's logic, and was absolutely incredible for that era, but times and technology do change. I don't think many of us want to go to the front of our cars with a crank to start them.

Sometimes you don't change what works very well! Like the 022 switches, although they are very old they work great with some lubrication and repair, may work even into the 22nd century if cared for properly.

I won't say that about most new stuff.

Lee Fritz

I agree with you, re the O22 switches. I have probably repaired 200 switches, most have been the O22. I can count on one hand the number that were fubar. The later generation, have to take my shoes off.

By the way, anyone wanting to follow our advice about adding a cheap transformer, you need to make sure it is phased right. If there are only 2 terminals on your train show find, then turn it on, do not hook it up to anything. Also turn on your layout transformer.  Take a piece of wire and attach it to one of the terminals on the new transformer. touch the wire to  the center rail and outside rail of your layout. which ever combination does not give you a spark is the right way to wire it, and you will be "in phase".

Why phase two transformers when you can buy a post war ZW or Z transformer and get four output controls? The post war Z is a 250 watt transformer without the whistle feature and it has a lot of power available for use. The Z transformer has the same issue as the post war ZW, the circuit breaker (most likely a 15 amp)is mounted on the common side and you will need to add 7 or 8 amp breakers to the A thru D terminals to make it safer.

Lee Fritz

$$

If you already have it, use it.

The KW also has 5 output ranges, instead of 4 on the Z & ZW, and has the same number of whistle/horn control circuits as the ZW, and 2 more than the Z.

Now, if you want to get really tricky, you can get a ZW to act like a KW quite easily.

That's interesting to know about the KW.

I have one of each transformer, a 275 watt ZW, 190 watt KW and a 250 watt Z.

Of course the Z don't have any whistle control as it's letter code don't have a W in it.

Lee Fritz

"...you need to make sure it is phased right."

As I mentioned many posts above, you do NOT need to phase multiple supplies UNLESS they are being used for traction power, on tracks that interconnect. (That is, third rails that are separated by an insulating pin, with the possibility that a locomotive or other rolling stock might bridge the gap with two interconnected rollers.)

If multiple supplies (AC, DC, various voltages) are used for activating accessories or switches, then all you need to do is to provide a common return, which is as easy as connecting EITHER output post of the "new" supply to the outside rail wire on the "old" transformer.

Thank you Arthur. Appreciate your thoughts.

Tinman wrote:  "...you need to make sure it is phased right."

Arthur Bloom wrote: "...you do NOT need to phase multiple supplies UNLESS they are being used for traction power, on tracks that interconnect.

If multiple supplies (AC, DC, various voltages) are used for activating accessories or switches, then all you need to do is to provide a common return, which is as easy as connecting EITHER output post of the "new" supply to the outside rail wire on the "old" transformer.

Arthur, I hate to disagree with you on this matter, because you give so generously of your time in providing excellent advice on electrical questions.  However, Tinman is correct in saying that added transformers must be in phase.  This is true even when the added transformer does not connect to the third rail of tracks that interconnect.

Let me just say that phasing to avoid roller sparking at the power district interconnections is important.  But it is vitally important as a prevention of personal injury from the electrical voltage differences.  An out of phase situation at the third rail gap (thus between two transformers) can double the maximum peak voltage difference from 42 volts to 84 volts with both the postwar KW & ZW, and the Z-4000. transformers.

This voltage is called the touch voltage, and the UL requirements are that all toy train transformers have no combination of posts that will have a difference in excess of 42 volts peak.  This is about 30 volts rms for a sine-wave voltage (30 x 1.4 = 42), and the NEC has been made uniform at 30 volts rms maximum for all touchable circuits.  (The abbreviation "rms" gives a single AC voltage of 30 which would deliver through a meter the same energy value as a 30-volt DC voltage.)

For safety, the peak voltage is important.  This voltage limit has a very old history.   Long ago, a serious accident occurred by contact with 44 volts DC; this has remained the lowest known such occurrence (involving dry skin contact by an adult).  It is now known that increasing frequency reduces the risk somewhat, and at present the issue is being further researched, notably in Florida.  I believe that the safety margin is somewhat greater than would appear from the history given.

Note that the postwar transformers were designed at a time when the US residential utilization voltage was 115 volts (parts of S. California used the Mexican voltage of 125; NYC in part used DC; the ZW core can be used at nominal 125 volts).  In the mid 50s the US residential voltage was increased to 120 volts (raising the 20-volt KW/ZW outputs to 21 volts); also normal power system operation permits 5% overvoltage.  I have included the US situation and 5% system overvoltage in stating the present peak output to be 42 volts.

So clearly a 1033 auxiliary transformer for 022 switch fixed voltage should be phased, just as other transformers, because its terminals can be touched.  For the 1033, the 3rd rail output terminal is the "U" terminal (in contrast to the large KW and ZW transformers, where the "U" terminals are the common return from the outside rails).  Also, the 1033 offers two ranges of variable output, U-A which is 5-15 volts and U-B which is 0-11 volts.  The choice is made by connecting A or B to the outside rail respectively.  You will immediately see that when operating in multiple with KW or ZW, it is the A post of 1033 which should be connected to the outside rail, and this is thus the proper common post in multiple.

The reason for this is that the posts lie along the two coils (five-volt fixed coil and 11-volt variable) in the order A-B--C-U (U in max voltage position).  If B is connected as common, then with A-B at 5 volts, the touch voltage on the layout will be increased by 9 volts (5 x 1.4) to 51 volts, which is not permissible.  Thus (unless the variable output is used for the switches fixed voltage plugs) the 11-volt fixed output (B-C, now 11.48 volts) will not be available to the fixed voltage plug of the 022 switches.

Should the variable U post of the 1033 not be available (perhaps in use for a yard switcher), the 15-volt fixed output (posts A-C, now 15.65 volts) is available.  It is worth remembering that the 12-volt bulb is an automotive bulb for a 12-volt car battery.  The charging voltage of a 12-volt car battery is 14.7 volts, which will be the rated bulb voltage.  Thus A-C will put an overvoltage of .95 volts on the bulb, or 6.46%.  This will decrease lamp life by about 13%.  Of course heat increases, so the lantern with a vent hole is indicated.  Or 18-volt lamps may be used.

By a similar line of reasoning, use of a 12-volt DC wall device is not indicated, because of its effect on touch voltage.  The increase on this layout will be to 55 volts peak, at a repetition rate of 60 maximum peaks per second, all with the same polarity (vs 120 alternating maximum peaks at 42 volts).  This would not be proper.

Observation of the touch voltage limit is probably the single most important safety measure on a toy train layout.  Hence the postwar effort to provide transformers of sufficient size that a single transformer could run the great majority of layouts.

I became more familiar with common wire issues while my firm were consultants to a major satellite communications company.  The most troublesome common wire was often the ground wire.  This was before the IEEE wrote the Orange Book (followed by the Purple Book and yet another) and even before the Internet became useful.  I'll post a few more safety comments as time permits.

--Frank

I use the 20 volt tap on my KWs to power 022 switches.  I put a diode in series with the lamps in the switches and controllers by putting a diode in series with each lamp.  This cuts the power by about 30 percent and keeps the lamps cool.  Check out my thread on fixing 022 switches:  022/711 switch operating pblms.  You can find it with Google.  It is very thorough and I recommend you use it for all your 022 switches.

Wow!!! Servo guy, you are the man! I read and will reread your art of repairing switches several more times.  I thought I knew all there was to know regarding O22 repairs, till I saw your work. I just received a large shipment of new version O72 switches. I do not expect to have the success with these guys as I have had with the O22's. There is another point re the diode in series with the bulbs.

Ever wonder why bulbs in cars last so long? Because they are not being slammed with the peaks and valleys of the AC sign wave. Also another treat for you. Take your 73 which I will bet anything that you use, and do a before and after test of current with and without the diode in series with the lamps. I never did understand why you get such a large wattage drop, but you do. It's not just the voltage drop. I have known this for years, but needed your inspiration to put that in perspective. One helpful tidbit I can add for switch repair> I use small terry cloth hand towels, the WD40 and a little elbow grease to clean the silver contacts. Seems the terry cloth has just enough abrasive to clean without scarring.

 Also thanks for taking the bull by the horns with your very diplomatic response to the phasing issue. My rationale was simple if you are getting a spark, looks like something is not quite right  to me.

Correction, thanks to F McGuire for your phasing info. I at one time owned a couple of commercial towers, which had very large incondasant yeah, I know it's spelled wrong, bulbs. On the top of the tower there were 2 750 watt bulbs. I found running a big time diode in series cut my electric cost over 60% and the reduction of brightness was hardly noticeable. Remember years ago you used to buy those little buttons that you would put into a light socket to reduce electricity cost? they were nothing more than a diode in series with the bulb, and they worked.

This is probably because someone did not recognize the advantage of having OUT of phase power supplies.

yup, especially in automotive apps.

Tin Man, I have been using a pencil eraser lately to clean the sliding contacts in the 022 switches.

BTW, I am up to about 125 022 switches, and 30+/- 711 & 072 switches.  

FYI, some of the newer 072 switches have coils in the switch motor with resistance as low as 2 ohms, and the fixed part of the sliding contacts is nothing more than copper on a PC board.  The PC board copper is easily burned of the voltage is too high.  The older motors work fine on 20 volts. 

I have tried to come up with a way to install a dpst micro switch in the assembly, but as of yet no success. By the way, a friend of mine who is a auto mechanic, corrected me for putting oil on the lantern gears. Has me now using lithium grease. The graphite idea intrigue's me for the slide switch though, what do you think? I get nervous about liquid oils anywhere near the contact areas.

Lithium grease will dry out and get hard.  I have been using motor oil on the 022 switches for 7 years with good results.  Oil will not cause problems with electrical contacts.  You do oil the axles on your locos, don't you?  The axle is in contact with the locomotive and provides an electrical circuit between the outer rail and the loco motor.

I have been oiling the commutators on my locos with good results.  I oil the rollers in my KW and ZW transformers.  I oil the whistle controllers, particularly in the KWs.

Tough to argue with success.